From 0178776293cefe4ce7efb08119d92ae5e134d188 Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Sun, 12 Oct 2025 17:03:41 -0400
Subject: [PATCH 01/26] feat(reexecution/c): decouple metrics server and
 collector

---
 .../c-chain-reexecution-benchmark/action.yml  |  2 +-
 Taskfile.yml                                  |  8 +-
 scripts/benchmark_cchain_range.sh             |  4 +-
 tests/reexecute/c/README.md                   | 15 +++-
 tests/reexecute/c/vm_reexecute_test.go        | 87 ++++++++++++++++---
 5 files changed, 94 insertions(+), 22 deletions(-)

diff --git a/.github/actions/c-chain-reexecution-benchmark/action.yml b/.github/actions/c-chain-reexecution-benchmark/action.yml
index d0f119a02c80..523f28d63e79 100644
--- a/.github/actions/c-chain-reexecution-benchmark/action.yml
+++ b/.github/actions/c-chain-reexecution-benchmark/action.yml
@@ -95,7 +95,7 @@ runs:
             LABELS=${{ env.LABELS }} \
             BENCHMARK_OUTPUT_FILE=${{ env.BENCHMARK_OUTPUT_FILE }} \
             RUNNER_NAME=${{ inputs.runner_name }} \
-            METRICS_ENABLED=true
+            METRICS_MODE="full"
         prometheus_url: ${{ inputs.prometheus-url }}
         prometheus_push_url: ${{ inputs.prometheus-push-url }}
         prometheus_username: ${{ inputs.prometheus-username }}
diff --git a/Taskfile.yml b/Taskfile.yml
index 7f722c814bba..323127e15417 100644
--- a/Taskfile.yml
+++ b/Taskfile.yml
@@ -203,7 +203,7 @@ tasks:
       END_BLOCK: '{{.END_BLOCK}}'
       LABELS: '{{.LABELS | default ""}}'
       BENCHMARK_OUTPUT_FILE: '{{.BENCHMARK_OUTPUT_FILE | default ""}}'
-      METRICS_ENABLED: '{{.METRICS_ENABLED | default "false"}}'
+      METRICS_MODE: '{{.METRICS_MODE | default "disabled"}}'
     cmd: |
       CURRENT_STATE_DIR={{.CURRENT_STATE_DIR}} \
       BLOCK_DIR={{.BLOCK_DIR}} \
@@ -213,7 +213,7 @@ tasks:
       END_BLOCK={{.END_BLOCK}} \
       LABELS={{.LABELS}} \
       BENCHMARK_OUTPUT_FILE={{.BENCHMARK_OUTPUT_FILE}} \
-      METRICS_ENABLED={{.METRICS_ENABLED}} \
+      METRICS_MODE={{.METRICS_MODE}} \
       bash -x ./scripts/benchmark_cchain_range.sh
 
   reexecute-cchain-range-with-copied-data:
@@ -228,7 +228,7 @@ tasks:
       END_BLOCK: '{{.END_BLOCK | default "250000"}}'
       LABELS: '{{.LABELS | default ""}}'
       BENCHMARK_OUTPUT_FILE: '{{.BENCHMARK_OUTPUT_FILE | default ""}}'
-      METRICS_ENABLED: '{{.METRICS_ENABLED | default "false"}}'
+      METRICS_MODE: '{{.METRICS_MODE | default "disabled"}}'
     cmds:
       - task: import-cchain-reexecute-range
         vars:
@@ -245,7 +245,7 @@ tasks:
           END_BLOCK: '{{.END_BLOCK}}'
           LABELS: '{{.LABELS}}'
           BENCHMARK_OUTPUT_FILE: '{{.BENCHMARK_OUTPUT_FILE}}'
-          METRICS_ENABLED: '{{.METRICS_ENABLED}}'
+          METRICS_MODE: '{{.METRICS_MODE}}'
 
   test-bootstrap-monitor-e2e:
     desc: Runs bootstrap monitor e2e tests
diff --git a/scripts/benchmark_cchain_range.sh b/scripts/benchmark_cchain_range.sh
index 3072143da87a..9765eedbb610 100755
--- a/scripts/benchmark_cchain_range.sh
+++ b/scripts/benchmark_cchain_range.sh
@@ -25,10 +25,10 @@ cmd="go test -timeout=0 -v -benchtime=1x -bench=BenchmarkReexecuteRange -run=^$
   --start-block=\"${START_BLOCK}\" \
   --end-block=\"${END_BLOCK}\" \
   ${LABELS:+--labels=\"${LABELS}\"} \
-  ${METRICS_ENABLED:+--metrics-enabled=\"${METRICS_ENABLED}\"}"
+  ${METRICS_MODE:+--metrics-mode=\"${METRICS_MODE}\"}"
 
 if [ -n "${BENCHMARK_OUTPUT_FILE:-}" ]; then
   eval "$cmd" | tee "${BENCHMARK_OUTPUT_FILE}"
 else
   eval "$cmd"
-fi
\ No newline at end of file
+fi
diff --git a/tests/reexecute/c/README.md b/tests/reexecute/c/README.md
index f0f8fe6aa670..6cf4e34b42ac 100644
--- a/tests/reexecute/c/README.md
+++ b/tests/reexecute/c/README.md
@@ -42,7 +42,18 @@ export AWS_REGION=us-east-2
 
 ### Metrics Collection
 
-If running with metrics collection, enabled in CI and configured locally with `METRICS_ENABLED=true`, follow the instructions in the e2e [README](../../e2e/README.md#monitoring) to set the required Prometheus environment variables.
+If running locally, there are three options for metrics collection:
+
+- `METRICS_MODE=disabled`: no metrics are available.
+- `METRICS_MODE=server-only`: starts a Prometheus server exporting VM metrics. A
+  link to the metrics endpoint is logged during execution.
+- `METRICS_MODE=full`: starts both a Prometheus server exporting VM metrics and
+  a Prometheus collector. A link to the corresponding Grafana dashboard is
+  logged during execution.
+
+When utilizing the `full` options, follow the instructions in the e2e [README](../../e2e/README.md#monitoring) to set the required Prometheus environment variables.
+
+Running the re-execution test in CI will always set `METRICS_MODE=full`.
 
 ## Quick Start
 
@@ -230,7 +241,7 @@ The `CONFIG` parameter currently only supports pre-defined configs and not passi
 
 The C-Chain benchmarks export VM metrics to the same Grafana instance as AvalancheGo CI: https://grafana-poc.avax-dev.network/.
 
-To export metrics for a local run, simply set the Taskfile variable `METRICS_ENABLED=true` either via environment variable or passing it at the command line.
+To export metrics for a local run, simply set the Taskfile variable `METRICS_MODE=full` either via environment variable or passing it at the command line.
 
 You can view granular C-Chain processing metrics with the label attached to this job (job="c-chain-reexecution") [here](https://grafana-poc.avax-dev.network/d/Gl1I20mnk/c-chain?orgId=1&from=now-5m&to=now&timezone=browser&var-datasource=P1809F7CD0C75ACF3&var-filter=job%7C%3D%7Cc-chain-reexecution&var-chain=C&refresh=10s).
 
diff --git a/tests/reexecute/c/vm_reexecute_test.go b/tests/reexecute/c/vm_reexecute_test.go
index 9982da655e3d..1eaec7ea6ad0 100644
--- a/tests/reexecute/c/vm_reexecute_test.go
+++ b/tests/reexecute/c/vm_reexecute_test.go
@@ -48,6 +48,12 @@ import (
 	"github.com/ava-labs/avalanchego/vms/platformvm/warp"
 )
 
+const (
+	MetricsDisabled metricsMode = iota
+	MetricsServerOnly
+	MetricsFull
+)
+
 var (
 	mainnetXChainID    = ids.FromStringOrPanic("2oYMBNV4eNHyqk2fjjV5nVQLDbtmNJzq5s3qs3Lo6ftnC6FByM")
 	mainnetCChainID    = ids.FromStringOrPanic("2q9e4r6Mu3U68nU1fYjgbR6JvwrRx36CohpAX5UQxse55x1Q5")
@@ -62,10 +68,11 @@ var (
 	startBlockArg      uint64
 	endBlockArg        uint64
 	chanSizeArg        int
-	metricsEnabledArg  bool
 	executionTimeout   time.Duration
 	labelsArg          string
 
+	metricsModeArg = MetricsDisabled
+
 	networkUUID string = uuid.NewString()
 	labels             = map[string]string{
 		"job":               "c-chain-reexecution",
@@ -94,6 +101,41 @@ var (
 	configBytesArg []byte
 )
 
+type metricsMode int
+
+func (m *metricsMode) Set(s string) error {
+	s = strings.ToLower(strings.TrimSpace(s))
+
+	switch s {
+	case "disabled":
+		*m = MetricsDisabled
+	case "server-only":
+		*m = MetricsServerOnly
+	case "full":
+		*m = MetricsFull
+	default:
+		return fmt.Errorf("invalid metrics mode: %s (valid options: disabled, server-only, full)", s)
+	}
+	return nil
+}
+
+func (m metricsMode) String() string {
+	switch m {
+	case MetricsDisabled:
+		return "disabled"
+	case MetricsServerOnly:
+		return "server-only"
+	case MetricsFull:
+		return "full"
+	default:
+		return "unknown"
+	}
+}
+
+func (m metricsMode) shouldStartServer() bool { return m >= MetricsServerOnly }
+
+func (m metricsMode) shouldStartCollector() bool { return m == MetricsFull }
+
 func TestMain(m *testing.M) {
 	evm.RegisterAllLibEVMExtras()
 
@@ -104,7 +146,7 @@ func TestMain(m *testing.M) {
 	flag.IntVar(&chanSizeArg, "chan-size", 100, "Size of the channel to use for block processing.")
 	flag.DurationVar(&executionTimeout, "execution-timeout", 0, "Benchmark execution timeout. After this timeout has elapsed, terminate the benchmark without error. If 0, no timeout is applied.")
 
-	flag.BoolVar(&metricsEnabledArg, "metrics-enabled", false, "Enable metrics collection.")
+	flag.Var(&metricsModeArg, "metrics-mode", "Metrics mode: disabled (no metrics), server-only (creates Prometheus server), or full (creates Prometheus server and starts Prometheus collector)")
 	flag.StringVar(&labelsArg, "labels", "", "Comma separated KV list of metric labels to attach to all exported metrics. Ex. \"owner=tim,runner=snoopy\"")
 
 	predefinedConfigKeys := slices.Collect(maps.Keys(predefinedConfigs))
@@ -151,7 +193,7 @@ func BenchmarkReexecuteRange(b *testing.B) {
 			startBlockArg,
 			endBlockArg,
 			chanSizeArg,
-			metricsEnabledArg,
+			metricsModeArg,
 		)
 	})
 }
@@ -164,7 +206,7 @@ func benchmarkReexecuteRange(
 	startBlock uint64,
 	endBlock uint64,
 	chanSize int,
-	metricsEnabled bool,
+	metricsMode metricsMode,
 ) {
 	r := require.New(b)
 	ctx := context.Background()
@@ -185,9 +227,8 @@ func benchmarkReexecuteRange(
 	r.NoError(prefixGatherer.Register("avalanche_snowman", consensusRegistry))
 
 	log := tests.NewDefaultLogger("c-chain-reexecution")
-
-	if metricsEnabled {
-		collectRegistry(b, log, "c-chain-reexecution", prefixGatherer, labels)
+	if metricsMode.shouldStartServer() {
+		collectRegistry(b, log, "c-chain-reexecution", prefixGatherer, labels, metricsMode.shouldStartCollector())
 	}
 
 	var (
@@ -554,20 +595,40 @@ func newConsensusMetrics(registry prometheus.Registerer) (*consensusMetrics, err
 	return m, nil
 }
 
-// collectRegistry starts prometheus and collects metrics from the provided gatherer.
-// Attaches the provided labels + GitHub labels if available to the collected metrics.
-func collectRegistry(tb testing.TB, log logging.Logger, name string, gatherer prometheus.Gatherer, labels map[string]string) {
+// collectRegistry starts a Prometheus server for the provided gatherer. If
+// startCollector is true, then collectRegistry also starts a Prometheus
+// collector for the provided gatherer and attaches the provided labels + GitHub
+// labels if available to the collected metrics.
+func collectRegistry(
+	tb testing.TB,
+	log logging.Logger,
+	name string,
+	gatherer prometheus.Gatherer,
+	labels map[string]string,
+	startCollector bool,
+) {
 	r := require.New(tb)
 
+	server, err := tests.NewPrometheusServer(gatherer)
+	r.NoError(err)
+
+	if !startCollector {
+		log.Info("metrics endpoint available",
+			zap.String("url", fmt.Sprintf("http://%s/ext/metrics", server.Address())),
+		)
+
+		tb.Cleanup(func() {
+			r.NoError(server.Stop())
+		})
+		return
+	}
+
 	startPromCtx, cancel := context.WithTimeout(context.Background(), tests.DefaultTimeout)
 	defer cancel()
 
 	logger := tests.NewDefaultLogger("prometheus")
 	r.NoError(tmpnet.StartPrometheus(startPromCtx, logger))
 
-	server, err := tests.NewPrometheusServer(gatherer)
-	r.NoError(err)
-
 	var sdConfigFilePath string
 	tb.Cleanup(func() {
 		// Ensure a final metrics scrape.

From 848c6ade0d79f658248d600277d2ab3d1ff6b276 Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Mon, 13 Oct 2025 08:56:53 -0400
Subject: [PATCH 02/26] docs: improve collectRegistry

---
 tests/reexecute/c/vm_reexecute_test.go | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/reexecute/c/vm_reexecute_test.go b/tests/reexecute/c/vm_reexecute_test.go
index 1eaec7ea6ad0..e1c9b4403f58 100644
--- a/tests/reexecute/c/vm_reexecute_test.go
+++ b/tests/reexecute/c/vm_reexecute_test.go
@@ -596,8 +596,8 @@ func newConsensusMetrics(registry prometheus.Registerer) (*consensusMetrics, err
 }
 
 // collectRegistry starts a Prometheus server for the provided gatherer. If
-// startCollector is true, then collectRegistry also starts a Prometheus
-// collector for the provided gatherer and attaches the provided labels + GitHub
+// startCollector is true, it also starts a Prometheus collector configured to
+// scrape the Prometheus server and attaches the provided labels + GitHub
 // labels if available to the collected metrics.
 func collectRegistry(
 	tb testing.TB,

From be761ac79dee396423591a4f2c8736ca93c1a9ed Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Mon, 13 Oct 2025 12:41:59 -0400
Subject: [PATCH 03/26] chore: set default to empty string

---
 Taskfile.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Taskfile.yml b/Taskfile.yml
index 323127e15417..4b38da7f6df7 100644
--- a/Taskfile.yml
+++ b/Taskfile.yml
@@ -203,7 +203,7 @@ tasks:
       END_BLOCK: '{{.END_BLOCK}}'
       LABELS: '{{.LABELS | default ""}}'
       BENCHMARK_OUTPUT_FILE: '{{.BENCHMARK_OUTPUT_FILE | default ""}}'
-      METRICS_MODE: '{{.METRICS_MODE | default "disabled"}}'
+      METRICS_MODE: '{{.METRICS_MODE | default ""}}'
     cmd: |
       CURRENT_STATE_DIR={{.CURRENT_STATE_DIR}} \
       BLOCK_DIR={{.BLOCK_DIR}} \
@@ -228,7 +228,7 @@ tasks:
       END_BLOCK: '{{.END_BLOCK | default "250000"}}'
       LABELS: '{{.LABELS | default ""}}'
       BENCHMARK_OUTPUT_FILE: '{{.BENCHMARK_OUTPUT_FILE | default ""}}'
-      METRICS_MODE: '{{.METRICS_MODE | default "disabled"}}'
+      METRICS_MODE: '{{.METRICS_MODE | default ""}}'
     cmds:
       - task: import-cchain-reexecute-range
         vars:

From ca0b99391edf567577ebd9b057d64c255a06734f Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Mon, 13 Oct 2025 12:42:25 -0400
Subject: [PATCH 04/26] docs: benchmark script

---
 scripts/benchmark_cchain_range.sh | 1 +
 1 file changed, 1 insertion(+)

diff --git a/scripts/benchmark_cchain_range.sh b/scripts/benchmark_cchain_range.sh
index 9765eedbb610..29423f8c1777 100755
--- a/scripts/benchmark_cchain_range.sh
+++ b/scripts/benchmark_cchain_range.sh
@@ -10,6 +10,7 @@ set -euo pipefail
 #   END_BLOCK: The ending block height (inclusive).
 #   LABELS (optional): Comma-separated key=value pairs for metric labels.
 #   BENCHMARK_OUTPUT_FILE (optional): If set, benchmark output is also written to this file.
+#   METRICS_MODE (optional): If set, determines the metrics mode (disabled, server-only, or full).
 
 : "${BLOCK_DIR:?BLOCK_DIR must be set}"
 : "${CURRENT_STATE_DIR:?CURRENT_STATE_DIR must be set}"

From a7cb056696109f2f60ac980ef4341b2faba9188c Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Mon, 13 Oct 2025 14:05:29 -0400
Subject: [PATCH 05/26] chore: simplify metricsMode

---
 tests/reexecute/c/vm_reexecute_test.go | 53 +++++++++-----------------
 1 file changed, 17 insertions(+), 36 deletions(-)

diff --git a/tests/reexecute/c/vm_reexecute_test.go b/tests/reexecute/c/vm_reexecute_test.go
index e1c9b4403f58..b8fab14e7376 100644
--- a/tests/reexecute/c/vm_reexecute_test.go
+++ b/tests/reexecute/c/vm_reexecute_test.go
@@ -49,9 +49,9 @@ import (
 )
 
 const (
-	MetricsDisabled metricsMode = iota
-	MetricsServerOnly
-	MetricsFull
+	MetricsDisabled   = "disabled"
+	MetricsServerOnly = "server-only"
+	MetricsFull       = "full"
 )
 
 var (
@@ -70,8 +70,7 @@ var (
 	chanSizeArg        int
 	executionTimeout   time.Duration
 	labelsArg          string
-
-	metricsModeArg = MetricsDisabled
+	metricsModeArg     string
 
 	networkUUID string = uuid.NewString()
 	labels             = map[string]string{
@@ -101,38 +100,13 @@ var (
 	configBytesArg []byte
 )
 
-type metricsMode int
-
-func (m *metricsMode) Set(s string) error {
-	s = strings.ToLower(strings.TrimSpace(s))
-
-	switch s {
-	case "disabled":
-		*m = MetricsDisabled
-	case "server-only":
-		*m = MetricsServerOnly
-	case "full":
-		*m = MetricsFull
-	default:
-		return fmt.Errorf("invalid metrics mode: %s (valid options: disabled, server-only, full)", s)
-	}
-	return nil
-}
+type metricsMode string
 
-func (m metricsMode) String() string {
-	switch m {
-	case MetricsDisabled:
-		return "disabled"
-	case MetricsServerOnly:
-		return "server-only"
-	case MetricsFull:
-		return "full"
-	default:
-		return "unknown"
-	}
+func (m metricsMode) isValid() bool {
+	return m == MetricsDisabled || m == MetricsServerOnly || m == MetricsFull
 }
 
-func (m metricsMode) shouldStartServer() bool { return m >= MetricsServerOnly }
+func (m metricsMode) shouldStartServer() bool { return m == MetricsServerOnly || m == MetricsFull }
 
 func (m metricsMode) shouldStartCollector() bool { return m == MetricsFull }
 
@@ -146,7 +120,8 @@ func TestMain(m *testing.M) {
 	flag.IntVar(&chanSizeArg, "chan-size", 100, "Size of the channel to use for block processing.")
 	flag.DurationVar(&executionTimeout, "execution-timeout", 0, "Benchmark execution timeout. After this timeout has elapsed, terminate the benchmark without error. If 0, no timeout is applied.")
 
-	flag.Var(&metricsModeArg, "metrics-mode", "Metrics mode: disabled (no metrics), server-only (creates Prometheus server), or full (creates Prometheus server and starts Prometheus collector)")
+	metricsModes := strings.Join([]string{MetricsDisabled, MetricsServerOnly, MetricsFull}, ", ")
+	flag.StringVar(&metricsModeArg, "metrics-mode", MetricsDisabled, fmt.Sprintf("Specifies the type of metrics configuration. Options include %s.", metricsModes))
 	flag.StringVar(&labelsArg, "labels", "", "Comma separated KV list of metric labels to attach to all exported metrics. Ex. \"owner=tim,runner=snoopy\"")
 
 	predefinedConfigKeys := slices.Collect(maps.Keys(predefinedConfigs))
@@ -160,6 +135,12 @@ func TestMain(m *testing.M) {
 
 	flag.Parse()
 
+	mode := metricsMode(metricsModeArg)
+	if !mode.isValid() {
+		fmt.Fprintf(os.Stderr, "invalid metrics mode %q. Valid options include %s. \n", metricsModeArg, metricsModes)
+		os.Exit(1)
+	}
+
 	customLabels, err := parseCustomLabels(labelsArg)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "failed to parse labels: %v\n", err)
@@ -193,7 +174,7 @@ func BenchmarkReexecuteRange(b *testing.B) {
 			startBlockArg,
 			endBlockArg,
 			chanSizeArg,
-			metricsModeArg,
+			metricsMode(metricsModeArg),
 		)
 	})
 }

From c7f3185de4552ee54625443073ff4d55da48483f Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Mon, 13 Oct 2025 19:23:58 -0400
Subject: [PATCH 06/26] chore: unexport metricsMode

---
 tests/reexecute/c/vm_reexecute_test.go | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/tests/reexecute/c/vm_reexecute_test.go b/tests/reexecute/c/vm_reexecute_test.go
index d25b3e3708ff..a098e55b845d 100644
--- a/tests/reexecute/c/vm_reexecute_test.go
+++ b/tests/reexecute/c/vm_reexecute_test.go
@@ -48,9 +48,9 @@ import (
 )
 
 const (
-	MetricsDisabled   = "disabled"
-	MetricsServerOnly = "server-only"
-	MetricsFull       = "full"
+	metricsDisabled   = "disabled"
+	metricsServerOnly = "server-only"
+	metricsFull       = "full"
 )
 
 var (
@@ -102,12 +102,12 @@ var (
 type metricsMode string
 
 func (m metricsMode) isValid() bool {
-	return m == MetricsDisabled || m == MetricsServerOnly || m == MetricsFull
+	return m == metricsDisabled || m == metricsServerOnly || m == metricsFull
 }
 
-func (m metricsMode) shouldStartServer() bool { return m == MetricsServerOnly || m == MetricsFull }
+func (m metricsMode) shouldStartServer() bool { return m == metricsServerOnly || m == metricsFull }
 
-func (m metricsMode) shouldStartCollector() bool { return m == MetricsFull }
+func (m metricsMode) shouldStartCollector() bool { return m == metricsFull }
 
 func TestMain(m *testing.M) {
 	evm.RegisterAllLibEVMExtras()
@@ -119,8 +119,8 @@ func TestMain(m *testing.M) {
 	flag.IntVar(&chanSizeArg, "chan-size", 100, "Size of the channel to use for block processing.")
 	flag.DurationVar(&executionTimeout, "execution-timeout", 0, "Benchmark execution timeout. After this timeout has elapsed, terminate the benchmark without error. If 0, no timeout is applied.")
 
-	metricsModes := strings.Join([]string{MetricsDisabled, MetricsServerOnly, MetricsFull}, ", ")
-	flag.StringVar(&metricsModeArg, "metrics-mode", MetricsDisabled, fmt.Sprintf("Specifies the type of metrics configuration. Options include %s.", metricsModes))
+	metricsModes := strings.Join([]string{metricsDisabled, metricsServerOnly, metricsFull}, ", ")
+	flag.StringVar(&metricsModeArg, "metrics-mode", metricsDisabled, fmt.Sprintf("Specifies the type of metrics configuration. Options include %s.", metricsModes))
 	flag.StringVar(&labelsArg, "labels", "", "Comma separated KV list of metric labels to attach to all exported metrics. Ex. \"owner=tim,runner=snoopy\"")
 
 	predefinedConfigKeys := slices.Collect(maps.Keys(predefinedConfigs))

From 9e319d0ad4ca14d829023586fcb4adb1f42a63c2 Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Mon, 13 Oct 2025 19:52:21 -0400
Subject: [PATCH 07/26] chore: clean up

---
 tests/reexecute/c/vm_reexecute_test.go | 49 ++++++++++++++------------
 1 file changed, 26 insertions(+), 23 deletions(-)

diff --git a/tests/reexecute/c/vm_reexecute_test.go b/tests/reexecute/c/vm_reexecute_test.go
index a098e55b845d..9f64a2620449 100644
--- a/tests/reexecute/c/vm_reexecute_test.go
+++ b/tests/reexecute/c/vm_reexecute_test.go
@@ -105,10 +105,6 @@ func (m metricsMode) isValid() bool {
 	return m == metricsDisabled || m == metricsServerOnly || m == metricsFull
 }
 
-func (m metricsMode) shouldStartServer() bool { return m == metricsServerOnly || m == metricsFull }
-
-func (m metricsMode) shouldStartCollector() bool { return m == metricsFull }
-
 func TestMain(m *testing.M) {
 	evm.RegisterAllLibEVMExtras()
 
@@ -204,8 +200,13 @@ func benchmarkReexecuteRange(
 	r.NoError(prefixGatherer.Register("avalanche_snowman", consensusRegistry))
 
 	log := tests.NewDefaultLogger("c-chain-reexecution")
-	if metricsMode.shouldStartServer() {
-		collectRegistry(b, log, "c-chain-reexecution", prefixGatherer, labels, metricsMode.shouldStartCollector())
+
+	switch metricsMode {
+	case metricsServerOnly:
+		startServer(b, log, prefixGatherer)
+	case metricsFull:
+		collectRegistry(b, log, "c-chain-reexecution", prefixGatherer, labels)
+	case metricsDisabled:
 	}
 
 	var (
@@ -568,33 +569,32 @@ func newConsensusMetrics(registry prometheus.Registerer) (*consensusMetrics, err
 	return m, nil
 }
 
-// collectRegistry starts a Prometheus server for the provided gatherer. If
-// startCollector is true, it also starts a Prometheus collector configured to
-// scrape the Prometheus server and attaches the provided labels + GitHub
-// labels if available to the collected metrics.
-func collectRegistry(
+// startServer starts a Prometheus server for the provided gatherer.
+func startServer(
 	tb testing.TB,
 	log logging.Logger,
-	name string,
 	gatherer prometheus.Gatherer,
-	labels map[string]string,
-	startCollector bool,
 ) {
 	r := require.New(tb)
 
 	server, err := tests.NewPrometheusServer(gatherer)
 	r.NoError(err)
 
-	if !startCollector {
-		log.Info("metrics endpoint available",
-			zap.String("url", fmt.Sprintf("http://%s/ext/metrics", server.Address())),
-		)
+	log.Info("metrics endpoint available",
+		zap.String("url", fmt.Sprintf("http://%s/ext/metrics", server.Address())),
+	)
 
-		tb.Cleanup(func() {
-			r.NoError(server.Stop())
-		})
-		return
-	}
+	tb.Cleanup(func() {
+		r.NoError(server.Stop())
+	})
+}
+
+// collectRegistry starts a Prometheus server for the provided gatherer and
+// starts a Prometheus collector configured to scrape the Prometheus server.
+// collectRegistry also attaches the provided labels + Github labels if
+// available to the collected metrics.
+func collectRegistry(tb testing.TB, log logging.Logger, name string, gatherer prometheus.Gatherer, labels map[string]string) {
+	r := require.New(tb)
 
 	startPromCtx, cancel := context.WithTimeout(context.Background(), tests.DefaultTimeout)
 	defer cancel()
@@ -602,6 +602,9 @@ func collectRegistry(
 	logger := tests.NewDefaultLogger("prometheus")
 	r.NoError(tmpnet.StartPrometheus(startPromCtx, logger))
 
+	server, err := tests.NewPrometheusServer(gatherer)
+	r.NoError(err)
+
 	var sdConfigFilePath string
 	tb.Cleanup(func() {
 		// Ensure a final metrics scrape.

From 2cc0a790f6f3a37ca369a78622aeabdc0b4d6310 Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Tue, 14 Oct 2025 08:16:28 -0400
Subject: [PATCH 08/26] chore: self-review nits

---
 tests/reexecute/c/vm_reexecute_test.go | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tests/reexecute/c/vm_reexecute_test.go b/tests/reexecute/c/vm_reexecute_test.go
index 9f64a2620449..ac0f74a53f6c 100644
--- a/tests/reexecute/c/vm_reexecute_test.go
+++ b/tests/reexecute/c/vm_reexecute_test.go
@@ -205,7 +205,7 @@ func benchmarkReexecuteRange(
 	case metricsServerOnly:
 		startServer(b, log, prefixGatherer)
 	case metricsFull:
-		collectRegistry(b, log, "c-chain-reexecution", prefixGatherer, labels)
+		startServerAndCollector(b, log, "c-chain-reexecution", prefixGatherer, labels)
 	case metricsDisabled:
 	}
 
@@ -589,11 +589,11 @@ func startServer(
 	})
 }
 
-// collectRegistry starts a Prometheus server for the provided gatherer and
+// startServerAndCollector starts a Prometheus server for the provided gatherer and
 // starts a Prometheus collector configured to scrape the Prometheus server.
-// collectRegistry also attaches the provided labels + Github labels if
+// startServerAndCollector also attaches the provided labels + Github labels if
 // available to the collected metrics.
-func collectRegistry(tb testing.TB, log logging.Logger, name string, gatherer prometheus.Gatherer, labels map[string]string) {
+func startServerAndCollector(tb testing.TB, log logging.Logger, name string, gatherer prometheus.Gatherer, labels map[string]string) {
 	r := require.New(tb)
 
 	startPromCtx, cancel := context.WithTimeout(context.Background(), tests.DefaultTimeout)

From feb16819cd832dc9e289b8b059178496ad2d28d3 Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Tue, 14 Oct 2025 09:17:48 -0400
Subject: [PATCH 09/26] feat(reexecute/c): explicit metrics port

---
 Taskfile.yml                           |  4 ++++
 scripts/benchmark_cchain_range.sh      |  4 +++-
 tests/load/main/main.go                |  2 +-
 tests/prometheus_server.go             | 21 +++++++++++++--------
 tests/reexecute/c/vm_reexecute_test.go | 22 +++++++++++++++++-----
 5 files changed, 38 insertions(+), 15 deletions(-)

diff --git a/Taskfile.yml b/Taskfile.yml
index 4b38da7f6df7..58a1f8967c4f 100644
--- a/Taskfile.yml
+++ b/Taskfile.yml
@@ -204,6 +204,7 @@ tasks:
       LABELS: '{{.LABELS | default ""}}'
       BENCHMARK_OUTPUT_FILE: '{{.BENCHMARK_OUTPUT_FILE | default ""}}'
       METRICS_MODE: '{{.METRICS_MODE | default ""}}'
+      METRICS_SERVER_PORT: '{{.METRICS_SERVER_PORT}}'
     cmd: |
       CURRENT_STATE_DIR={{.CURRENT_STATE_DIR}} \
       BLOCK_DIR={{.BLOCK_DIR}} \
@@ -214,6 +215,7 @@ tasks:
       LABELS={{.LABELS}} \
       BENCHMARK_OUTPUT_FILE={{.BENCHMARK_OUTPUT_FILE}} \
       METRICS_MODE={{.METRICS_MODE}} \
+      METRICS_SERVER_PORT={{.METRICS_SERVER_PORT}} \
       bash -x ./scripts/benchmark_cchain_range.sh
 
   reexecute-cchain-range-with-copied-data:
@@ -229,6 +231,7 @@ tasks:
       LABELS: '{{.LABELS | default ""}}'
       BENCHMARK_OUTPUT_FILE: '{{.BENCHMARK_OUTPUT_FILE | default ""}}'
       METRICS_MODE: '{{.METRICS_MODE | default ""}}'
+      METRICS_SERVER_PORT: '{{.METRICS_SERVER_PORT}}'
     cmds:
       - task: import-cchain-reexecute-range
         vars:
@@ -246,6 +249,7 @@ tasks:
           LABELS: '{{.LABELS}}'
           BENCHMARK_OUTPUT_FILE: '{{.BENCHMARK_OUTPUT_FILE}}'
           METRICS_MODE: '{{.METRICS_MODE}}'
+          METRICS_SERVER_PORT: '{{.METRICS_SERVER_PORT}}'
 
   test-bootstrap-monitor-e2e:
     desc: Runs bootstrap monitor e2e tests
diff --git a/scripts/benchmark_cchain_range.sh b/scripts/benchmark_cchain_range.sh
index 29423f8c1777..f72feb96bc82 100755
--- a/scripts/benchmark_cchain_range.sh
+++ b/scripts/benchmark_cchain_range.sh
@@ -11,6 +11,7 @@ set -euo pipefail
 #   LABELS (optional): Comma-separated key=value pairs for metric labels.
 #   BENCHMARK_OUTPUT_FILE (optional): If set, benchmark output is also written to this file.
 #   METRICS_MODE (optional): If set, determines the metrics mode (disabled, server-only, or full).
+#   METRICS_SERVER_PORT (optional): If set, determines the port the metrics server will listen to.
 
 : "${BLOCK_DIR:?BLOCK_DIR must be set}"
 : "${CURRENT_STATE_DIR:?CURRENT_STATE_DIR must be set}"
@@ -26,7 +27,8 @@ cmd="go test -timeout=0 -v -benchtime=1x -bench=BenchmarkReexecuteRange -run=^$
   --start-block=\"${START_BLOCK}\" \
   --end-block=\"${END_BLOCK}\" \
   ${LABELS:+--labels=\"${LABELS}\"} \
-  ${METRICS_MODE:+--metrics-mode=\"${METRICS_MODE}\"}"
+  ${METRICS_MODE:+--metrics-mode=\"${METRICS_MODE}\"} \
+  ${METRICS_SERVER_PORT:+--metrics-server-port=\"${METRICS_SERVER_PORT}\"}"
 
 if [ -n "${BENCHMARK_OUTPUT_FILE:-}" ]; then
   eval "$cmd" | tee "${BENCHMARK_OUTPUT_FILE}"
diff --git a/tests/load/main/main.go b/tests/load/main/main.go
index a2ad0c51c3a9..7a7a4d1052a9 100644
--- a/tests/load/main/main.go
+++ b/tests/load/main/main.go
@@ -102,7 +102,7 @@ func main() {
 	require.NoError(err)
 
 	registry := prometheus.NewRegistry()
-	metricsServer, err := tests.NewPrometheusServer(registry)
+	metricsServer, err := tests.NewPrometheusServer(registry, tests.DefaultMetricsPort)
 	require.NoError(err)
 	tc.DeferCleanup(func() {
 		require.NoError(metricsServer.Stop())
diff --git a/tests/prometheus_server.go b/tests/prometheus_server.go
index c87a61e7fc98..99fe18d1cf6c 100644
--- a/tests/prometheus_server.go
+++ b/tests/prometheus_server.go
@@ -6,6 +6,7 @@ package tests
 import (
 	"context"
 	"errors"
+	"fmt"
 	"net"
 	"net/http"
 	"time"
@@ -14,7 +15,10 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
-const defaultPrometheusListenAddr = "127.0.0.1:0"
+const (
+	localhostAddr      = "127.0.0.1"
+	DefaultMetricsPort = 0
+)
 
 // PrometheusServer is a HTTP server that serves Prometheus metrics from the provided
 // gahterer.
@@ -26,27 +30,28 @@ type PrometheusServer struct {
 }
 
 // NewPrometheusServer creates and starts a Prometheus server with the provided gatherer
-// listening on 127.0.0.1:0 and serving /ext/metrics.
-func NewPrometheusServer(gatherer prometheus.Gatherer) (*PrometheusServer, error) {
+// listening on 127.0.0.1:port and serving /ext/metrics.
+func NewPrometheusServer(gatherer prometheus.Gatherer, port uint64) (*PrometheusServer, error) {
 	server := &PrometheusServer{
 		gatherer: gatherer,
 	}
 
-	if err := server.start(); err != nil {
+	prometheusListenAddr := fmt.Sprintf("%s:%d", localhostAddr, port)
+	if err := server.start(prometheusListenAddr); err != nil {
 		return nil, err
 	}
 
 	return server, nil
 }
 
-// start the Prometheus server on a dynamic port.
-func (s *PrometheusServer) start() error {
+// start the Prometheus server on prometheusListenAddr.
+func (s *PrometheusServer) start(prometheusListenAddr string) error {
 	mux := http.NewServeMux()
 	mux.Handle("/ext/metrics", promhttp.HandlerFor(s.gatherer, promhttp.HandlerOpts{}))
 
-	listener, err := net.Listen("tcp", defaultPrometheusListenAddr)
+	listener, err := net.Listen("tcp", prometheusListenAddr)
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to listen on %s: %w", prometheusListenAddr, err)
 	}
 
 	s.server = http.Server{
diff --git a/tests/reexecute/c/vm_reexecute_test.go b/tests/reexecute/c/vm_reexecute_test.go
index ac0f74a53f6c..d942095b4ca4 100644
--- a/tests/reexecute/c/vm_reexecute_test.go
+++ b/tests/reexecute/c/vm_reexecute_test.go
@@ -70,6 +70,7 @@ var (
 	executionTimeout   time.Duration
 	labelsArg          string
 	metricsModeArg     string
+	metricsServerPort  uint64
 
 	networkUUID string = uuid.NewString()
 	labels             = map[string]string{
@@ -117,6 +118,7 @@ func TestMain(m *testing.M) {
 
 	metricsModes := strings.Join([]string{metricsDisabled, metricsServerOnly, metricsFull}, ", ")
 	flag.StringVar(&metricsModeArg, "metrics-mode", metricsDisabled, fmt.Sprintf("Specifies the type of metrics configuration. Options include %s.", metricsModes))
+	flag.Uint64Var(&metricsServerPort, "metrics-server-port", tests.DefaultMetricsPort, "Port which metrics server will listen to (metrics mode must be either server-only or full)")
 	flag.StringVar(&labelsArg, "labels", "", "Comma separated KV list of metric labels to attach to all exported metrics. Ex. \"owner=tim,runner=snoopy\"")
 
 	predefinedConfigKeys := slices.Collect(maps.Keys(predefinedConfigs))
@@ -170,6 +172,7 @@ func BenchmarkReexecuteRange(b *testing.B) {
 			endBlockArg,
 			chanSizeArg,
 			metricsMode(metricsModeArg),
+			metricsServerPort,
 		)
 	})
 }
@@ -183,6 +186,7 @@ func benchmarkReexecuteRange(
 	endBlock uint64,
 	chanSize int,
 	metricsMode metricsMode,
+	metricsServerPort uint64,
 ) {
 	r := require.New(b)
 	ctx := context.Background()
@@ -203,9 +207,9 @@ func benchmarkReexecuteRange(
 
 	switch metricsMode {
 	case metricsServerOnly:
-		startServer(b, log, prefixGatherer)
+		startServer(b, log, prefixGatherer, metricsServerPort)
 	case metricsFull:
-		startServerAndCollector(b, log, "c-chain-reexecution", prefixGatherer, labels)
+		startServerAndCollector(b, log, "c-chain-reexecution", prefixGatherer, labels, metricsServerPort)
 	case metricsDisabled:
 	}
 
@@ -574,10 +578,11 @@ func startServer(
 	tb testing.TB,
 	log logging.Logger,
 	gatherer prometheus.Gatherer,
+	port uint64,
 ) {
 	r := require.New(tb)
 
-	server, err := tests.NewPrometheusServer(gatherer)
+	server, err := tests.NewPrometheusServer(gatherer, port)
 	r.NoError(err)
 
 	log.Info("metrics endpoint available",
@@ -593,7 +598,14 @@ func startServer(
 // starts a Prometheus collector configured to scrape the Prometheus server.
 // startServerAndCollector also attaches the provided labels + Github labels if
 // available to the collected metrics.
-func startServerAndCollector(tb testing.TB, log logging.Logger, name string, gatherer prometheus.Gatherer, labels map[string]string) {
+func startServerAndCollector(
+	tb testing.TB,
+	log logging.Logger,
+	name string,
+	gatherer prometheus.Gatherer,
+	labels map[string]string,
+	port uint64,
+) {
 	r := require.New(tb)
 
 	startPromCtx, cancel := context.WithTimeout(context.Background(), tests.DefaultTimeout)
@@ -602,7 +614,7 @@ func startServerAndCollector(tb testing.TB, log logging.Logger, name string, gat
 	logger := tests.NewDefaultLogger("prometheus")
 	r.NoError(tmpnet.StartPrometheus(startPromCtx, logger))
 
-	server, err := tests.NewPrometheusServer(gatherer)
+	server, err := tests.NewPrometheusServer(gatherer, port)
 	r.NoError(err)
 
 	var sdConfigFilePath string

From a5d4392ef450b6b45fecedbb284d7347da8a92c2 Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Mon, 20 Oct 2025 10:33:28 -0400
Subject: [PATCH 10/26] chore: nits

---
 tests/reexecute/c/vm_reexecute_test.go | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/tests/reexecute/c/vm_reexecute_test.go b/tests/reexecute/c/vm_reexecute_test.go
index 4ac0fdeddc8d..3e3970d3708b 100644
--- a/tests/reexecute/c/vm_reexecute_test.go
+++ b/tests/reexecute/c/vm_reexecute_test.go
@@ -46,12 +46,6 @@ import (
 	"github.com/ava-labs/avalanchego/vms/platformvm/warp"
 )
 
-const (
-	metricsDisabled   = "disabled"
-	metricsServerOnly = "server-only"
-	metricsFull       = "full"
-)
-
 var (
 	mainnetXChainID    = ids.FromStringOrPanic("2oYMBNV4eNHyqk2fjjV5nVQLDbtmNJzq5s3qs3Lo6ftnC6FByM")
 	mainnetCChainID    = ids.FromStringOrPanic("2q9e4r6Mu3U68nU1fYjgbR6JvwrRx36CohpAX5UQxse55x1Q5")
@@ -101,12 +95,6 @@ var (
 	configBytesArg []byte
 )
 
-type metricsMode string
-
-func (m metricsMode) isValid() bool {
-	return m == metricsDisabled || m == metricsServerOnly || m == metricsFull
-}
-
 func TestMain(m *testing.M) {
 	evm.RegisterAllLibEVMExtras()
 
@@ -173,6 +161,7 @@ func BenchmarkReexecuteRange(b *testing.B) {
 			chanSizeArg,
 			metricsServerEnabledArg,
 			metricsCollectorEnabledArg,
+			metricsServerPort,
 		)
 	})
 }
@@ -187,6 +176,7 @@ func benchmarkReexecuteRange(
 	chanSize int,
 	metricsServerEnabled bool,
 	metricsCollectorEnabled bool,
+	metricsPort uint64,
 ) {
 	r := require.New(b)
 	ctx := context.Background()
@@ -206,7 +196,7 @@ func benchmarkReexecuteRange(
 	log := tests.NewDefaultLogger("c-chain-reexecution")
 
 	if metricsServerEnabled {
-		serverAddr := startServer(b, log, prefixGatherer)
+		serverAddr := startServer(b, log, prefixGatherer, metricsPort)
 
 		if metricsCollectorEnabled {
 			startCollector(b, log, "c-chain-reexecution", labels, serverAddr)
@@ -579,10 +569,11 @@ func startServer(
 	tb testing.TB,
 	log logging.Logger,
 	gatherer prometheus.Gatherer,
+	port uint64,
 ) string {
 	r := require.New(tb)
 
-	server, err := tests.NewPrometheusServer(gatherer)
+	server, err := tests.NewPrometheusServer(gatherer, port)
 	r.NoError(err)
 
 	log.Info("metrics endpoint available",

From c67da7fceb44bc3fa509be0683ef393ee63435c3 Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Mon, 20 Oct 2025 14:31:22 -0400
Subject: [PATCH 11/26] chore: nits

---
 tests/prometheus_server.go | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/tests/prometheus_server.go b/tests/prometheus_server.go
index 99fe18d1cf6c..b5c52af947dc 100644
--- a/tests/prometheus_server.go
+++ b/tests/prometheus_server.go
@@ -16,8 +16,9 @@ import (
 )
 
 const (
-	localhostAddr      = "127.0.0.1"
 	DefaultMetricsPort = 0
+
+	localhostAddr = "127.0.0.1"
 )
 
 // PrometheusServer is a HTTP server that serves Prometheus metrics from the provided
@@ -36,22 +37,22 @@ func NewPrometheusServer(gatherer prometheus.Gatherer, port uint64) (*Prometheus
 		gatherer: gatherer,
 	}
 
-	prometheusListenAddr := fmt.Sprintf("%s:%d", localhostAddr, port)
-	if err := server.start(prometheusListenAddr); err != nil {
+	serverAddress := fmt.Sprintf("%s:%d", localhostAddr, port)
+	if err := server.start(serverAddress); err != nil {
 		return nil, err
 	}
 
 	return server, nil
 }
 
-// start the Prometheus server on prometheusListenAddr.
-func (s *PrometheusServer) start(prometheusListenAddr string) error {
+// start the Prometheus server on address.
+func (s *PrometheusServer) start(address string) error {
 	mux := http.NewServeMux()
 	mux.Handle("/ext/metrics", promhttp.HandlerFor(s.gatherer, promhttp.HandlerOpts{}))
 
-	listener, err := net.Listen("tcp", prometheusListenAddr)
+	listener, err := net.Listen("tcp", address)
 	if err != nil {
-		return fmt.Errorf("failed to listen on %s: %w", prometheusListenAddr, err)
+		return fmt.Errorf("failed to listen on %s: %w", address, err)
 	}
 
 	s.server = http.Server{

From f5e2e14b8e3f93665f6e5c8370095f3ca6fd0bd6 Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Mon, 20 Oct 2025 14:40:59 -0400
Subject: [PATCH 12/26] chore: unexport consts

---
 tests/load/main/main.go                |  2 +-
 tests/prometheus_server.go             | 13 +++++++++----
 tests/reexecute/c/vm_reexecute_test.go |  4 ++--
 3 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/tests/load/main/main.go b/tests/load/main/main.go
index 7a7a4d1052a9..a2ad0c51c3a9 100644
--- a/tests/load/main/main.go
+++ b/tests/load/main/main.go
@@ -102,7 +102,7 @@ func main() {
 	require.NoError(err)
 
 	registry := prometheus.NewRegistry()
-	metricsServer, err := tests.NewPrometheusServer(registry, tests.DefaultMetricsPort)
+	metricsServer, err := tests.NewPrometheusServer(registry)
 	require.NoError(err)
 	tc.DeferCleanup(func() {
 		require.NoError(metricsServer.Stop())
diff --git a/tests/prometheus_server.go b/tests/prometheus_server.go
index b5c52af947dc..3b48226f0ac7 100644
--- a/tests/prometheus_server.go
+++ b/tests/prometheus_server.go
@@ -16,9 +16,8 @@ import (
 )
 
 const (
-	DefaultMetricsPort = 0
-
-	localhostAddr = "127.0.0.1"
+	localhostAddr      = "127.0.0.1"
+	defaultMetricsPort = 0
 )
 
 // PrometheusServer is a HTTP server that serves Prometheus metrics from the provided
@@ -30,9 +29,15 @@ type PrometheusServer struct {
 	errChan  chan error
 }
 
+// NewPrometheusServer creates and starts a Prometheus server with the provided gatherer
+// listening on 127.0.0.1:0 and serving /ext/metrics.
+func NewPrometheusServer(gatherer prometheus.Gatherer) (*PrometheusServer, error) {
+	return NewPrometheusServerWithPort(gatherer, defaultMetricsPort)
+}
+
 // NewPrometheusServer creates and starts a Prometheus server with the provided gatherer
 // listening on 127.0.0.1:port and serving /ext/metrics.
-func NewPrometheusServer(gatherer prometheus.Gatherer, port uint64) (*PrometheusServer, error) {
+func NewPrometheusServerWithPort(gatherer prometheus.Gatherer, port uint64) (*PrometheusServer, error) {
 	server := &PrometheusServer{
 		gatherer: gatherer,
 	}
diff --git a/tests/reexecute/c/vm_reexecute_test.go b/tests/reexecute/c/vm_reexecute_test.go
index 3e3970d3708b..4f8ad312833f 100644
--- a/tests/reexecute/c/vm_reexecute_test.go
+++ b/tests/reexecute/c/vm_reexecute_test.go
@@ -107,7 +107,7 @@ func TestMain(m *testing.M) {
 
 	flag.BoolVar(&metricsServerEnabledArg, "metrics-server-enabled", false, "Whether to enable the metrics server.")
 	flag.BoolVar(&metricsCollectorEnabledArg, "metrics-collector-enabled", false, "Whether to enable the metrics collector (if true, then metrics-server-enabled must be true as well).")
-	flag.Uint64Var(&metricsServerPort, "metrics-server-port", tests.DefaultMetricsPort, "Port which metrics server will listen to (metrics mode must be either server-only or full)")
+	flag.Uint64Var(&metricsServerPort, "metrics-server-port", metricsServerPort, "Port which metrics server will listen to (metrics mode must be either server-only or full)")
 	flag.StringVar(&labelsArg, "labels", "", "Comma separated KV list of metric labels to attach to all exported metrics. Ex. \"owner=tim,runner=snoopy\"")
 
 	predefinedConfigKeys := slices.Collect(maps.Keys(predefinedConfigs))
@@ -573,7 +573,7 @@ func startServer(
 ) string {
 	r := require.New(tb)
 
-	server, err := tests.NewPrometheusServer(gatherer, port)
+	server, err := tests.NewPrometheusServerWithPort(gatherer, port)
 	r.NoError(err)
 
 	log.Info("metrics endpoint available",

From d871c75ef4c1c301fa3518f0db213fc5624c66b4 Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Mon, 20 Oct 2025 14:44:55 -0400
Subject: [PATCH 13/26] chore: README

---
 tests/reexecute/c/README.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/reexecute/c/README.md b/tests/reexecute/c/README.md
index 07b01d4d8117..a020165234eb 100644
--- a/tests/reexecute/c/README.md
+++ b/tests/reexecute/c/README.md
@@ -46,6 +46,7 @@ If running locally, metrics collection can be customized via the following param
 
 - `METRICS_SERVER_ENABLED`: starts a Prometheus server exporting VM metrics.
 - `METRICS_COLLECTOR_ENABLED`: starts a Prometheus collector (if enabled, then `METRICS_SERVER_ENABLED` must be enabled as well).
+- `METRICS_SERVER_PORT`: determines the port the metrics server will listen to (set to `0` by default)
 
 When utilizing the metrics collector feature, follow the instructions in the e2e [README](../../e2e/README.md#monitoring) to set the required Prometheus environment variables.
 

From 540d60f17553ecbc6a56c0d753c6d88894ee637d Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Mon, 20 Oct 2025 14:48:04 -0400
Subject: [PATCH 14/26] chore: nit

---
 tests/reexecute/c/vm_reexecute_test.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/reexecute/c/vm_reexecute_test.go b/tests/reexecute/c/vm_reexecute_test.go
index 4f8ad312833f..452ecf95bd72 100644
--- a/tests/reexecute/c/vm_reexecute_test.go
+++ b/tests/reexecute/c/vm_reexecute_test.go
@@ -107,7 +107,7 @@ func TestMain(m *testing.M) {
 
 	flag.BoolVar(&metricsServerEnabledArg, "metrics-server-enabled", false, "Whether to enable the metrics server.")
 	flag.BoolVar(&metricsCollectorEnabledArg, "metrics-collector-enabled", false, "Whether to enable the metrics collector (if true, then metrics-server-enabled must be true as well).")
-	flag.Uint64Var(&metricsServerPort, "metrics-server-port", metricsServerPort, "Port which metrics server will listen to (metrics mode must be either server-only or full)")
+	flag.Uint64Var(&metricsServerPort, "metrics-server-port", metricsServerPort, "Port which the metrics server will listen to")
 	flag.StringVar(&labelsArg, "labels", "", "Comma separated KV list of metric labels to attach to all exported metrics. Ex. \"owner=tim,runner=snoopy\"")
 
 	predefinedConfigKeys := slices.Collect(maps.Keys(predefinedConfigs))

From bca6d48cc62c47dc9945919869d61ad71202a59b Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Mon, 20 Oct 2025 15:41:12 -0400
Subject: [PATCH 15/26] chore: nit

---
 Taskfile.yml                      | 4 ++--
 scripts/benchmark_cchain_range.sh | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/Taskfile.yml b/Taskfile.yml
index 3e60ae2b8856..f669240dcd4c 100644
--- a/Taskfile.yml
+++ b/Taskfile.yml
@@ -217,7 +217,7 @@ tasks:
       BENCHMARK_OUTPUT_FILE={{.BENCHMARK_OUTPUT_FILE}} \
       METRICS_SERVER_ENABLED={{.METRICS_SERVER_ENABLED}} \
       METRICS_COLLECTOR_ENABLED={{.METRICS_COLLECTOR_ENABLED}} \
-      METRICS_SERVER_PORT={{.METRICS_COLLECTOR_SERVER_PORT}} \
+      METRICS_SERVER_PORT={{.METRICS_SERVER_PORT}} \
       bash -x ./scripts/benchmark_cchain_range.sh
 
   reexecute-cchain-range-with-copied-data:
@@ -253,7 +253,7 @@ tasks:
           BENCHMARK_OUTPUT_FILE: '{{.BENCHMARK_OUTPUT_FILE}}'
           METRICS_SERVER_ENABLED: '{{.METRICS_SERVER_ENABLED}}'
           METRICS_COLLECTOR_ENABLED: '{{.METRICS_COLLECTOR_ENABLED}}'
-          METRICS_SERVER_PORT: '{{.METRICS_COLLECTOR_SERVER_PORT}}'
+          METRICS_SERVER_PORT: '{{.METRICS_SERVER_PORT}}'
 
   test-bootstrap-monitor-e2e:
     desc: Runs bootstrap monitor e2e tests
diff --git a/scripts/benchmark_cchain_range.sh b/scripts/benchmark_cchain_range.sh
index 35c0763a2fbb..481197216dff 100755
--- a/scripts/benchmark_cchain_range.sh
+++ b/scripts/benchmark_cchain_range.sh
@@ -30,7 +30,7 @@ cmd="go test -timeout=0 -v -benchtime=1x -bench=BenchmarkReexecuteRange -run=^$
   ${LABELS:+--labels=\"${LABELS}\"} \
   ${METRICS_SERVER_ENABLED:+--metrics-server-enabled=\"${METRICS_SERVER_ENABLED}\"} \
   ${METRICS_COLLECTOR_ENABLED:+--metrics-collector-enabled=\"${METRICS_COLLECTOR_ENABLED}\"} \
-  ${METRICS_SERVER_PORT:+--metrics-collector-server-port=\"${METRICS_COLLECTOR_SERVER_PORT}\"}"
+  ${METRICS_SERVER_PORT:+--metrics-server-port=\"${METRICS_SERVER_PORT}\"}"
 
 if [ -n "${BENCHMARK_OUTPUT_FILE:-}" ]; then
   eval "$cmd" | tee "${BENCHMARK_OUTPUT_FILE}"

From ac02cbf380a72f4752977dc464a940798a0e2735 Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Tue, 28 Oct 2025 08:15:45 -0400
Subject: [PATCH 16/26] docs: func name

---
 tests/prometheus_server.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/prometheus_server.go b/tests/prometheus_server.go
index 3b48226f0ac7..07b02c4f4c37 100644
--- a/tests/prometheus_server.go
+++ b/tests/prometheus_server.go
@@ -35,7 +35,7 @@ func NewPrometheusServer(gatherer prometheus.Gatherer) (*PrometheusServer, error
 	return NewPrometheusServerWithPort(gatherer, defaultMetricsPort)
 }
 
-// NewPrometheusServer creates and starts a Prometheus server with the provided gatherer
+// NewPrometheusServerWithPort creates and starts a Prometheus server with the provided gatherer
 // listening on 127.0.0.1:port and serving /ext/metrics.
 func NewPrometheusServerWithPort(gatherer prometheus.Gatherer, port uint64) (*PrometheusServer, error) {
 	server := &PrometheusServer{

From 46542061fe98287717ea358d33ea3ef0ea7ae17e Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Tue, 28 Oct 2025 14:26:27 -0400
Subject: [PATCH 17/26] chore: unify server flags

---
 .../c-chain-reexecution-benchmark/action.yml  |  2 +-
 Taskfile.yml                                  | 11 +++-----
 scripts/benchmark_cchain_range.sh             |  6 ++---
 tests/reexecute/c/vm_reexecute_test.go        | 25 +++++++++++--------
 4 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/.github/actions/c-chain-reexecution-benchmark/action.yml b/.github/actions/c-chain-reexecution-benchmark/action.yml
index 3385ff50a0c1..d1658d62d117 100644
--- a/.github/actions/c-chain-reexecution-benchmark/action.yml
+++ b/.github/actions/c-chain-reexecution-benchmark/action.yml
@@ -95,7 +95,7 @@ runs:
             LABELS=${{ env.LABELS }} \
             BENCHMARK_OUTPUT_FILE=${{ env.BENCHMARK_OUTPUT_FILE }} \
             RUNNER_NAME=${{ inputs.runner_name }} \
-            METRICS_SERVER_ENABLED=true \
+            METRICS_SERVER_PORT=0 \
             METRICS_COLLECTOR_ENABLED=true
         prometheus_url: ${{ inputs.prometheus-url }}
         prometheus_push_url: ${{ inputs.prometheus-push-url }}
diff --git a/Taskfile.yml b/Taskfile.yml
index 1f5acb199cd2..8713a4024a9b 100644
--- a/Taskfile.yml
+++ b/Taskfile.yml
@@ -207,9 +207,8 @@ tasks:
       END_BLOCK: '{{.END_BLOCK}}'
       LABELS: '{{.LABELS | default ""}}'
       BENCHMARK_OUTPUT_FILE: '{{.BENCHMARK_OUTPUT_FILE | default ""}}'
-      METRICS_SERVER_ENABLED: '{{.METRICS_SERVER_ENABLED | default "false"}}'
-      METRICS_COLLECTOR_ENABLED: '{{.METRICS_COLLECTOR_ENABLED | default "false"}}'
       METRICS_SERVER_PORT: '{{.METRICS_SERVER_PORT}}'
+      METRICS_COLLECTOR_ENABLED: '{{.METRICS_COLLECTOR_ENABLED | default "false"}}'
     cmd: |
       CURRENT_STATE_DIR={{.CURRENT_STATE_DIR}} \
       BLOCK_DIR={{.BLOCK_DIR}} \
@@ -219,9 +218,9 @@ tasks:
       END_BLOCK={{.END_BLOCK}} \
       LABELS={{.LABELS}} \
       BENCHMARK_OUTPUT_FILE={{.BENCHMARK_OUTPUT_FILE}} \
-      METRICS_SERVER_ENABLED={{.METRICS_SERVER_ENABLED}} \
       METRICS_COLLECTOR_ENABLED={{.METRICS_COLLECTOR_ENABLED}} \
       METRICS_SERVER_PORT={{.METRICS_SERVER_PORT}} \
+      METRICS_COLLECTOR_ENABLED={{.METRICS_COLLECTOR_ENABLED}} \
       bash -x ./scripts/benchmark_cchain_range.sh
 
   reexecute-cchain-range-with-copied-data:
@@ -236,9 +235,8 @@ tasks:
       END_BLOCK: '{{.END_BLOCK | default "250000"}}'
       LABELS: '{{.LABELS | default ""}}'
       BENCHMARK_OUTPUT_FILE: '{{.BENCHMARK_OUTPUT_FILE | default ""}}'
-      METRICS_SERVER_ENABLED: '{{.METRICS_SERVER_ENABLED | default "false"}}'
-      METRICS_COLLECTOR_ENABLED: '{{.METRICS_COLLECTOR_ENABLED | default "false"}}'
       METRICS_SERVER_PORT: '{{.METRICS_SERVER_PORT}}'
+      METRICS_COLLECTOR_ENABLED: '{{.METRICS_COLLECTOR_ENABLED | default "false"}}'
     cmds:
       - task: import-cchain-reexecute-range
         vars:
@@ -255,9 +253,8 @@ tasks:
           END_BLOCK: '{{.END_BLOCK}}'
           LABELS: '{{.LABELS}}'
           BENCHMARK_OUTPUT_FILE: '{{.BENCHMARK_OUTPUT_FILE}}'
-          METRICS_SERVER_ENABLED: '{{.METRICS_SERVER_ENABLED}}'
-          METRICS_COLLECTOR_ENABLED: '{{.METRICS_COLLECTOR_ENABLED}}'
           METRICS_SERVER_PORT: '{{.METRICS_SERVER_PORT}}'
+          METRICS_COLLECTOR_ENABLED: '{{.METRICS_COLLECTOR_ENABLED}}'
 
   test-bootstrap-monitor-e2e:
     desc: Runs bootstrap monitor e2e tests
diff --git a/scripts/benchmark_cchain_range.sh b/scripts/benchmark_cchain_range.sh
index 481197216dff..9038516a68d3 100755
--- a/scripts/benchmark_cchain_range.sh
+++ b/scripts/benchmark_cchain_range.sh
@@ -10,7 +10,6 @@ set -euo pipefail
 #   END_BLOCK: The ending block height (inclusive).
 #   LABELS (optional): Comma-separated key=value pairs for metric labels.
 #   BENCHMARK_OUTPUT_FILE (optional): If set, benchmark output is also written to this file.
-#   METRICS_SERVER_ENABLED (optional): If set, enables the metrics server.
 #   METRICS_COLLECTOR_ENABLED (optional): If set, enables the metrics collector.
 #   METRICS_SERVER_PORT (optional): If set, determines the port the metrics server will listen to.
 
@@ -28,9 +27,8 @@ cmd="go test -timeout=0 -v -benchtime=1x -bench=BenchmarkReexecuteRange -run=^$
   --start-block=\"${START_BLOCK}\" \
   --end-block=\"${END_BLOCK}\" \
   ${LABELS:+--labels=\"${LABELS}\"} \
-  ${METRICS_SERVER_ENABLED:+--metrics-server-enabled=\"${METRICS_SERVER_ENABLED}\"} \
-  ${METRICS_COLLECTOR_ENABLED:+--metrics-collector-enabled=\"${METRICS_COLLECTOR_ENABLED}\"} \
-  ${METRICS_SERVER_PORT:+--metrics-server-port=\"${METRICS_SERVER_PORT}\"}"
+  ${METRICS_SERVER_PORT:+--metrics-server-port=\"${METRICS_SERVER_PORT}\"}" \
+  ${METRICS_COLLECTOR_ENABLED:+--metrics-collector-enabled=\"${METRICS_COLLECTOR_ENABLED}\"}
 
 if [ -n "${BENCHMARK_OUTPUT_FILE:-}" ]; then
   eval "$cmd" | tee "${BENCHMARK_OUTPUT_FILE}"
diff --git a/tests/reexecute/c/vm_reexecute_test.go b/tests/reexecute/c/vm_reexecute_test.go
index 02bc153631c6..beb941fea2b2 100644
--- a/tests/reexecute/c/vm_reexecute_test.go
+++ b/tests/reexecute/c/vm_reexecute_test.go
@@ -63,9 +63,8 @@ var (
 	executionTimeout   time.Duration
 	labelsArg          string
 
-	metricsServerEnabledArg    bool
+	metricsServerPort          *uint64
 	metricsCollectorEnabledArg bool
-	metricsServerPort          uint64
 
 	networkUUID string = uuid.NewString()
 	labels             = map[string]string{
@@ -105,9 +104,17 @@ func TestMain(m *testing.M) {
 	flag.IntVar(&chanSizeArg, "chan-size", 100, "Size of the channel to use for block processing.")
 	flag.DurationVar(&executionTimeout, "execution-timeout", 0, "Benchmark execution timeout. After this timeout has elapsed, terminate the benchmark without error. If 0, no timeout is applied.")
 
-	flag.BoolVar(&metricsServerEnabledArg, "metrics-server-enabled", false, "Whether to enable the metrics server.")
+	flag.Func("metrics-server-port", "Port which the metrics server will listen to", func(s string) error {
+		port, err := strconv.ParseUint(s, 10, 64)
+		if err != nil {
+			return err
+		}
+
+		metricsServerPort = new(uint64)
+		*metricsServerPort = port
+		return nil
+	})
 	flag.BoolVar(&metricsCollectorEnabledArg, "metrics-collector-enabled", false, "Whether to enable the metrics collector (if true, then metrics-server-enabled must be true as well).")
-	flag.Uint64Var(&metricsServerPort, "metrics-server-port", metricsServerPort, "Port which the metrics server will listen to")
 	flag.StringVar(&labelsArg, "labels", "", "Comma separated KV list of metric labels to attach to all exported metrics. Ex. \"owner=tim,runner=snoopy\"")
 
 	predefinedConfigKeys := slices.Collect(maps.Keys(predefinedConfigs))
@@ -121,7 +128,7 @@ func TestMain(m *testing.M) {
 
 	flag.Parse()
 
-	if metricsCollectorEnabledArg && !metricsServerEnabledArg {
+	if metricsCollectorEnabledArg && metricsServerPort == nil {
 		fmt.Fprint(os.Stderr, "metrics collector is enabled but metrics server is disabled.\n")
 		os.Exit(1)
 	}
@@ -159,7 +166,6 @@ func BenchmarkReexecuteRange(b *testing.B) {
 			startBlockArg,
 			endBlockArg,
 			chanSizeArg,
-			metricsServerEnabledArg,
 			metricsCollectorEnabledArg,
 			metricsServerPort,
 		)
@@ -174,9 +180,8 @@ func benchmarkReexecuteRange(
 	startBlock uint64,
 	endBlock uint64,
 	chanSize int,
-	metricsServerEnabled bool,
 	metricsCollectorEnabled bool,
-	metricsPort uint64,
+	metricsPort *uint64,
 ) {
 	r := require.New(b)
 	ctx := b.Context()
@@ -195,8 +200,8 @@ func benchmarkReexecuteRange(
 
 	log := tests.NewDefaultLogger("c-chain-reexecution")
 
-	if metricsServerEnabled {
-		serverAddr := startServer(b, log, prefixGatherer, metricsPort)
+	if metricsPort != nil {
+		serverAddr := startServer(b, log, prefixGatherer, *metricsPort)
 
 		if metricsCollectorEnabled {
 			startCollector(b, log, "c-chain-reexecution", labels, serverAddr)

From d18bbb8c7f905917b865cf2cb75b96d40ce267c2 Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Tue, 28 Oct 2025 14:28:31 -0400
Subject: [PATCH 18/26] chore: nit

---
 scripts/benchmark_cchain_range.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/benchmark_cchain_range.sh b/scripts/benchmark_cchain_range.sh
index 9038516a68d3..b36d54e5ffa0 100755
--- a/scripts/benchmark_cchain_range.sh
+++ b/scripts/benchmark_cchain_range.sh
@@ -10,8 +10,8 @@ set -euo pipefail
 #   END_BLOCK: The ending block height (inclusive).
 #   LABELS (optional): Comma-separated key=value pairs for metric labels.
 #   BENCHMARK_OUTPUT_FILE (optional): If set, benchmark output is also written to this file.
-#   METRICS_COLLECTOR_ENABLED (optional): If set, enables the metrics collector.
 #   METRICS_SERVER_PORT (optional): If set, determines the port the metrics server will listen to.
+#   METRICS_COLLECTOR_ENABLED (optional): If set, enables the metrics collector.
 
 : "${BLOCK_DIR:?BLOCK_DIR must be set}"
 : "${CURRENT_STATE_DIR:?CURRENT_STATE_DIR must be set}"

From df721f1f21145d1e0ad2bdd7e306cf002fd736ac Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Tue, 28 Oct 2025 14:38:24 -0400
Subject: [PATCH 19/26] fix: quote

---
 scripts/benchmark_cchain_range.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scripts/benchmark_cchain_range.sh b/scripts/benchmark_cchain_range.sh
index b36d54e5ffa0..b2ed5e7b015b 100755
--- a/scripts/benchmark_cchain_range.sh
+++ b/scripts/benchmark_cchain_range.sh
@@ -27,8 +27,8 @@ cmd="go test -timeout=0 -v -benchtime=1x -bench=BenchmarkReexecuteRange -run=^$
   --start-block=\"${START_BLOCK}\" \
   --end-block=\"${END_BLOCK}\" \
   ${LABELS:+--labels=\"${LABELS}\"} \
-  ${METRICS_SERVER_PORT:+--metrics-server-port=\"${METRICS_SERVER_PORT}\"}" \
-  ${METRICS_COLLECTOR_ENABLED:+--metrics-collector-enabled=\"${METRICS_COLLECTOR_ENABLED}\"}
+  ${METRICS_SERVER_PORT:+--metrics-server-port=\"${METRICS_SERVER_PORT}\"} \
+  ${METRICS_COLLECTOR_ENABLED:+--metrics-collector-enabled=\"${METRICS_COLLECTOR_ENABLED}\"}"
 
 if [ -n "${BENCHMARK_OUTPUT_FILE:-}" ]; then
   eval "$cmd" | tee "${BENCHMARK_OUTPUT_FILE}"

From 527b652f0ec6d1ec2e23809c013c576a1c6d62f9 Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Tue, 28 Oct 2025 14:39:20 -0400
Subject: [PATCH 20/26] feat: implicitly enable metrics server if collector is
 enabled

---
 tests/reexecute/c/vm_reexecute_test.go | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/tests/reexecute/c/vm_reexecute_test.go b/tests/reexecute/c/vm_reexecute_test.go
index beb941fea2b2..e3a421dcc4c2 100644
--- a/tests/reexecute/c/vm_reexecute_test.go
+++ b/tests/reexecute/c/vm_reexecute_test.go
@@ -129,8 +129,7 @@ func TestMain(m *testing.M) {
 	flag.Parse()
 
 	if metricsCollectorEnabledArg && metricsServerPort == nil {
-		fmt.Fprint(os.Stderr, "metrics collector is enabled but metrics server is disabled.\n")
-		os.Exit(1)
+		metricsServerPort = new(uint64)
 	}
 
 	customLabels, err := parseCustomLabels(labelsArg)

From f2fc7948393d0cce17aa105b0acfceb335ad3dab Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Tue, 28 Oct 2025 14:43:21 -0400
Subject: [PATCH 21/26] chore: nits

---
 .github/actions/c-chain-reexecution-benchmark/action.yml | 1 -
 Taskfile.yml                                             | 1 -
 2 files changed, 2 deletions(-)

diff --git a/.github/actions/c-chain-reexecution-benchmark/action.yml b/.github/actions/c-chain-reexecution-benchmark/action.yml
index d1658d62d117..27149323332c 100644
--- a/.github/actions/c-chain-reexecution-benchmark/action.yml
+++ b/.github/actions/c-chain-reexecution-benchmark/action.yml
@@ -95,7 +95,6 @@ runs:
             LABELS=${{ env.LABELS }} \
             BENCHMARK_OUTPUT_FILE=${{ env.BENCHMARK_OUTPUT_FILE }} \
             RUNNER_NAME=${{ inputs.runner_name }} \
-            METRICS_SERVER_PORT=0 \
             METRICS_COLLECTOR_ENABLED=true
         prometheus_url: ${{ inputs.prometheus-url }}
         prometheus_push_url: ${{ inputs.prometheus-push-url }}
diff --git a/Taskfile.yml b/Taskfile.yml
index 8713a4024a9b..9abe50402d75 100644
--- a/Taskfile.yml
+++ b/Taskfile.yml
@@ -218,7 +218,6 @@ tasks:
       END_BLOCK={{.END_BLOCK}} \
       LABELS={{.LABELS}} \
       BENCHMARK_OUTPUT_FILE={{.BENCHMARK_OUTPUT_FILE}} \
-      METRICS_COLLECTOR_ENABLED={{.METRICS_COLLECTOR_ENABLED}} \
       METRICS_SERVER_PORT={{.METRICS_SERVER_PORT}} \
       METRICS_COLLECTOR_ENABLED={{.METRICS_COLLECTOR_ENABLED}} \
       bash -x ./scripts/benchmark_cchain_range.sh

From f156a76da198df390d41e51dc9ce8fdecc230387 Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Tue, 28 Oct 2025 14:50:35 -0400
Subject: [PATCH 22/26] docs: README

---
 tests/reexecute/c/README.md | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/tests/reexecute/c/README.md b/tests/reexecute/c/README.md
index a020165234eb..d4cfdc00b49a 100644
--- a/tests/reexecute/c/README.md
+++ b/tests/reexecute/c/README.md
@@ -44,13 +44,13 @@ export AWS_REGION=us-east-2
 
 If running locally, metrics collection can be customized via the following parameters:
 
-- `METRICS_SERVER_ENABLED`: starts a Prometheus server exporting VM metrics.
-- `METRICS_COLLECTOR_ENABLED`: starts a Prometheus collector (if enabled, then `METRICS_SERVER_ENABLED` must be enabled as well).
-- `METRICS_SERVER_PORT`: determines the port the metrics server will listen to (set to `0` by default)
+
+- `METRICS_SERVER_PORT`: if set, starts a metrics server and sets the port the server will listen to.
+- `METRICS_COLLECTOR_ENABLED`: starts a Prometheus collector. If `METRICS_SERVER_PORT` is not set, enabling the collector implicitly sets `METRICS_SERVER_PORT` to `0`.
 
 When utilizing the metrics collector feature, follow the instructions in the e2e [README](../../e2e/README.md#monitoring) to set the required Prometheus environment variables.
 
-Running the re-execution test in CI will always set `METRICS_SERVER_ENABLED=true` and `METRICS_COLLECTOR_ENABLED=true`.
+Running the re-execution test in CI will always set `METRICS_COLLECTOR_ENABLED=true`.
 
 ## Quick Start
 
@@ -238,7 +238,7 @@ The `CONFIG` parameter currently only supports pre-defined configs and not passi
 
 The C-Chain benchmarks export VM metrics to the same Grafana instance as AvalancheGo CI: https://grafana-poc.avax-dev.network/.
 
-To export metrics for a local run, simply set the Taskfile variables `METRICS_SERVER_ENABLED=true` and `METRICS_COLLECTOR_ENABLED=true` either via environment variable or passing it at the command line.
+To export metrics for a local run, simply set the Taskfile variable `METRICS_COLLECTOR_ENABLED=true` either via environment variable or passing it at the command line.
 
 You can view granular C-Chain processing metrics with the label attached to this job (job="c-chain-reexecution") [here](https://grafana-poc.avax-dev.network/d/Gl1I20mnk/c-chain?orgId=1&from=now-5m&to=now&timezone=browser&var-datasource=P1809F7CD0C75ACF3&var-filter=job%7C%3D%7Cc-chain-reexecution&var-chain=C&refresh=10s).
 

From 5bb04be7d5a760569a28547e856c7d348c56eb97 Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Tue, 28 Oct 2025 14:51:20 -0400
Subject: [PATCH 23/26] chore: nit

---
 tests/reexecute/c/README.md | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tests/reexecute/c/README.md b/tests/reexecute/c/README.md
index d4cfdc00b49a..314d15a6c5f8 100644
--- a/tests/reexecute/c/README.md
+++ b/tests/reexecute/c/README.md
@@ -44,7 +44,6 @@ export AWS_REGION=us-east-2
 
 If running locally, metrics collection can be customized via the following parameters:
 
-
 - `METRICS_SERVER_PORT`: if set, starts a metrics server and sets the port the server will listen to.
 - `METRICS_COLLECTOR_ENABLED`: starts a Prometheus collector. If `METRICS_SERVER_PORT` is not set, enabling the collector implicitly sets `METRICS_SERVER_PORT` to `0`.
 

From d0b0083cc9492fa97843d39bff341540879f7b88 Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Tue, 28 Oct 2025 15:08:45 -0400
Subject: [PATCH 24/26] docs: flag usage

---
 tests/reexecute/c/vm_reexecute_test.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/reexecute/c/vm_reexecute_test.go b/tests/reexecute/c/vm_reexecute_test.go
index e3a421dcc4c2..b7d6d7158c7b 100644
--- a/tests/reexecute/c/vm_reexecute_test.go
+++ b/tests/reexecute/c/vm_reexecute_test.go
@@ -104,7 +104,7 @@ func TestMain(m *testing.M) {
 	flag.IntVar(&chanSizeArg, "chan-size", 100, "Size of the channel to use for block processing.")
 	flag.DurationVar(&executionTimeout, "execution-timeout", 0, "Benchmark execution timeout. After this timeout has elapsed, terminate the benchmark without error. If 0, no timeout is applied.")
 
-	flag.Func("metrics-server-port", "Port which the metrics server will listen to", func(s string) error {
+	flag.Func("metrics-server-port", "Starts a metrics server and sets the port it will listen to", func(s string) error {
 		port, err := strconv.ParseUint(s, 10, 64)
 		if err != nil {
 			return err

From 830e8c1303d4cd93bd61f3192b3a9ddc0dc63c2d Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Tue, 28 Oct 2025 15:12:00 -0400
Subject: [PATCH 25/26] chore: nits

---
 tests/reexecute/c/README.md            | 2 +-
 tests/reexecute/c/vm_reexecute_test.go | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tests/reexecute/c/README.md b/tests/reexecute/c/README.md
index 314d15a6c5f8..870e6bca12e8 100644
--- a/tests/reexecute/c/README.md
+++ b/tests/reexecute/c/README.md
@@ -44,7 +44,7 @@ export AWS_REGION=us-east-2
 
 If running locally, metrics collection can be customized via the following parameters:
 
-- `METRICS_SERVER_PORT`: if set, starts a metrics server and sets the port the server will listen to.
+- `METRICS_SERVER_PORT`: if set, starts a Prometheus server exporting VM metrics and sets the port the server will listen to.
 - `METRICS_COLLECTOR_ENABLED`: starts a Prometheus collector. If `METRICS_SERVER_PORT` is not set, enabling the collector implicitly sets `METRICS_SERVER_PORT` to `0`.
 
 When utilizing the metrics collector feature, follow the instructions in the e2e [README](../../e2e/README.md#monitoring) to set the required Prometheus environment variables.
diff --git a/tests/reexecute/c/vm_reexecute_test.go b/tests/reexecute/c/vm_reexecute_test.go
index b7d6d7158c7b..43cebd37301a 100644
--- a/tests/reexecute/c/vm_reexecute_test.go
+++ b/tests/reexecute/c/vm_reexecute_test.go
@@ -165,8 +165,8 @@ func BenchmarkReexecuteRange(b *testing.B) {
 			startBlockArg,
 			endBlockArg,
 			chanSizeArg,
-			metricsCollectorEnabledArg,
 			metricsServerPort,
+			metricsCollectorEnabledArg,
 		)
 	})
 }
@@ -179,8 +179,8 @@ func benchmarkReexecuteRange(
 	startBlock uint64,
 	endBlock uint64,
 	chanSize int,
-	metricsCollectorEnabled bool,
 	metricsPort *uint64,
+	metricsCollectorEnabled bool,
 ) {
 	r := require.New(b)
 	ctx := b.Context()

From 3651f47d23ab1bd1ffa627acea5493689bb43059 Mon Sep 17 00:00:00 2001
From: Rodrigo Villar <rodrigo.villar@avalabs.org>
Date: Wed, 29 Oct 2025 09:16:19 -0400
Subject: [PATCH 26/26] chore: revert unification of metrics server param

---
 .../c-chain-reexecution-benchmark/action.yml  |  1 +
 Taskfile.yml                                  |  4 +++
 scripts/benchmark_cchain_range.sh             |  2 ++
 tests/reexecute/c/README.md                   |  9 +++---
 tests/reexecute/c/vm_reexecute_test.go        | 29 ++++++++-----------
 5 files changed, 24 insertions(+), 21 deletions(-)

diff --git a/.github/actions/c-chain-reexecution-benchmark/action.yml b/.github/actions/c-chain-reexecution-benchmark/action.yml
index 27149323332c..3385ff50a0c1 100644
--- a/.github/actions/c-chain-reexecution-benchmark/action.yml
+++ b/.github/actions/c-chain-reexecution-benchmark/action.yml
@@ -95,6 +95,7 @@ runs:
             LABELS=${{ env.LABELS }} \
             BENCHMARK_OUTPUT_FILE=${{ env.BENCHMARK_OUTPUT_FILE }} \
             RUNNER_NAME=${{ inputs.runner_name }} \
+            METRICS_SERVER_ENABLED=true \
             METRICS_COLLECTOR_ENABLED=true
         prometheus_url: ${{ inputs.prometheus-url }}
         prometheus_push_url: ${{ inputs.prometheus-push-url }}
diff --git a/Taskfile.yml b/Taskfile.yml
index 9abe50402d75..fa229d51d012 100644
--- a/Taskfile.yml
+++ b/Taskfile.yml
@@ -207,6 +207,7 @@ tasks:
       END_BLOCK: '{{.END_BLOCK}}'
       LABELS: '{{.LABELS | default ""}}'
       BENCHMARK_OUTPUT_FILE: '{{.BENCHMARK_OUTPUT_FILE | default ""}}'
+      METRICS_SERVER_ENABLED: '{{.METRICS_SERVER_ENABLED | default "false"}}'
       METRICS_SERVER_PORT: '{{.METRICS_SERVER_PORT}}'
       METRICS_COLLECTOR_ENABLED: '{{.METRICS_COLLECTOR_ENABLED | default "false"}}'
     cmd: |
@@ -218,6 +219,7 @@ tasks:
       END_BLOCK={{.END_BLOCK}} \
       LABELS={{.LABELS}} \
       BENCHMARK_OUTPUT_FILE={{.BENCHMARK_OUTPUT_FILE}} \
+      METRICS_SERVER_ENABLED={{.METRICS_SERVER_ENABLED}} \
       METRICS_SERVER_PORT={{.METRICS_SERVER_PORT}} \
       METRICS_COLLECTOR_ENABLED={{.METRICS_COLLECTOR_ENABLED}} \
       bash -x ./scripts/benchmark_cchain_range.sh
@@ -234,6 +236,7 @@ tasks:
       END_BLOCK: '{{.END_BLOCK | default "250000"}}'
       LABELS: '{{.LABELS | default ""}}'
       BENCHMARK_OUTPUT_FILE: '{{.BENCHMARK_OUTPUT_FILE | default ""}}'
+      METRICS_SERVER_ENABLED: '{{.METRICS_SERVER_ENABLED | default "false"}}'
       METRICS_SERVER_PORT: '{{.METRICS_SERVER_PORT}}'
       METRICS_COLLECTOR_ENABLED: '{{.METRICS_COLLECTOR_ENABLED | default "false"}}'
     cmds:
@@ -252,6 +255,7 @@ tasks:
           END_BLOCK: '{{.END_BLOCK}}'
           LABELS: '{{.LABELS}}'
           BENCHMARK_OUTPUT_FILE: '{{.BENCHMARK_OUTPUT_FILE}}'
+          METRICS_SERVER_ENABLED: '{{.METRICS_SERVER_ENABLED}}'
           METRICS_SERVER_PORT: '{{.METRICS_SERVER_PORT}}'
           METRICS_COLLECTOR_ENABLED: '{{.METRICS_COLLECTOR_ENABLED}}'
 
diff --git a/scripts/benchmark_cchain_range.sh b/scripts/benchmark_cchain_range.sh
index b2ed5e7b015b..0d9d951e7194 100755
--- a/scripts/benchmark_cchain_range.sh
+++ b/scripts/benchmark_cchain_range.sh
@@ -10,6 +10,7 @@ set -euo pipefail
 #   END_BLOCK: The ending block height (inclusive).
 #   LABELS (optional): Comma-separated key=value pairs for metric labels.
 #   BENCHMARK_OUTPUT_FILE (optional): If set, benchmark output is also written to this file.
+#   METRICS_SERVER_ENABLED (optional): If set, enables the metrics server.
 #   METRICS_SERVER_PORT (optional): If set, determines the port the metrics server will listen to.
 #   METRICS_COLLECTOR_ENABLED (optional): If set, enables the metrics collector.
 
@@ -27,6 +28,7 @@ cmd="go test -timeout=0 -v -benchtime=1x -bench=BenchmarkReexecuteRange -run=^$
   --start-block=\"${START_BLOCK}\" \
   --end-block=\"${END_BLOCK}\" \
   ${LABELS:+--labels=\"${LABELS}\"} \
+  ${METRICS_SERVER_ENABLED:+--metrics-server-enabled=\"${METRICS_SERVER_ENABLED}\"} \
   ${METRICS_SERVER_PORT:+--metrics-server-port=\"${METRICS_SERVER_PORT}\"} \
   ${METRICS_COLLECTOR_ENABLED:+--metrics-collector-enabled=\"${METRICS_COLLECTOR_ENABLED}\"}"
 
diff --git a/tests/reexecute/c/README.md b/tests/reexecute/c/README.md
index 870e6bca12e8..03d918cc36a6 100644
--- a/tests/reexecute/c/README.md
+++ b/tests/reexecute/c/README.md
@@ -44,12 +44,13 @@ export AWS_REGION=us-east-2
 
 If running locally, metrics collection can be customized via the following parameters:
 
-- `METRICS_SERVER_PORT`: if set, starts a Prometheus server exporting VM metrics and sets the port the server will listen to.
-- `METRICS_COLLECTOR_ENABLED`: starts a Prometheus collector. If `METRICS_SERVER_PORT` is not set, enabling the collector implicitly sets `METRICS_SERVER_PORT` to `0`.
+- `METRICS_SERVER_ENABLED`: starts a Prometheus server exporting VM metrics.
+- `METRICS_SERVER_PORT`: if set, determines the port the Prometheus server will listen to (set to `0` by default).
+- `METRICS_COLLECTOR_ENABLED`: starts a Prometheus collector. If `METRICS_SERVER_ENABLED` is not set, enabling the collector implicitly sets `METRICS_SERVER_ENABLED` to `true`.
 
 When utilizing the metrics collector feature, follow the instructions in the e2e [README](../../e2e/README.md#monitoring) to set the required Prometheus environment variables.
 
-Running the re-execution test in CI will always set `METRICS_COLLECTOR_ENABLED=true`.
+Running the re-execution test in CI will always set `METRICS_SERVER_ENABLED=true` and `METRICS_COLLECTOR_ENABLED=true`.
 
 ## Quick Start
 
@@ -237,7 +238,7 @@ The `CONFIG` parameter currently only supports pre-defined configs and not passi
 
 The C-Chain benchmarks export VM metrics to the same Grafana instance as AvalancheGo CI: https://grafana-poc.avax-dev.network/.
 
-To export metrics for a local run, simply set the Taskfile variable `METRICS_COLLECTOR_ENABLED=true` either via environment variable or passing it at the command line.
+To export metrics for a local run, simply set the Taskfile variables `METRICS_SERVER_ENABLED=true` and `METRICS_COLLECTOR_ENABLED=true` either via environment variable or passing it at the command line.
 
 You can view granular C-Chain processing metrics with the label attached to this job (job="c-chain-reexecution") [here](https://grafana-poc.avax-dev.network/d/Gl1I20mnk/c-chain?orgId=1&from=now-5m&to=now&timezone=browser&var-datasource=P1809F7CD0C75ACF3&var-filter=job%7C%3D%7Cc-chain-reexecution&var-chain=C&refresh=10s).
 
diff --git a/tests/reexecute/c/vm_reexecute_test.go b/tests/reexecute/c/vm_reexecute_test.go
index 43cebd37301a..124ad589e571 100644
--- a/tests/reexecute/c/vm_reexecute_test.go
+++ b/tests/reexecute/c/vm_reexecute_test.go
@@ -63,7 +63,8 @@ var (
 	executionTimeout   time.Duration
 	labelsArg          string
 
-	metricsServerPort          *uint64
+	metricsServerEnabledArg    bool
+	metricsServerPortArg       uint64
 	metricsCollectorEnabledArg bool
 
 	networkUUID string = uuid.NewString()
@@ -104,16 +105,8 @@ func TestMain(m *testing.M) {
 	flag.IntVar(&chanSizeArg, "chan-size", 100, "Size of the channel to use for block processing.")
 	flag.DurationVar(&executionTimeout, "execution-timeout", 0, "Benchmark execution timeout. After this timeout has elapsed, terminate the benchmark without error. If 0, no timeout is applied.")
 
-	flag.Func("metrics-server-port", "Starts a metrics server and sets the port it will listen to", func(s string) error {
-		port, err := strconv.ParseUint(s, 10, 64)
-		if err != nil {
-			return err
-		}
-
-		metricsServerPort = new(uint64)
-		*metricsServerPort = port
-		return nil
-	})
+	flag.BoolVar(&metricsServerEnabledArg, "metrics-server-enabled", false, "Whether to enable the metrics server.")
+	flag.Uint64Var(&metricsServerPortArg, "metrics-server-port", 0, "The port the metrics server will listen to.")
 	flag.BoolVar(&metricsCollectorEnabledArg, "metrics-collector-enabled", false, "Whether to enable the metrics collector (if true, then metrics-server-enabled must be true as well).")
 	flag.StringVar(&labelsArg, "labels", "", "Comma separated KV list of metric labels to attach to all exported metrics. Ex. \"owner=tim,runner=snoopy\"")
 
@@ -128,8 +121,8 @@ func TestMain(m *testing.M) {
 
 	flag.Parse()
 
-	if metricsCollectorEnabledArg && metricsServerPort == nil {
-		metricsServerPort = new(uint64)
+	if metricsCollectorEnabledArg {
+		metricsServerEnabledArg = true
 	}
 
 	customLabels, err := parseCustomLabels(labelsArg)
@@ -165,7 +158,8 @@ func BenchmarkReexecuteRange(b *testing.B) {
 			startBlockArg,
 			endBlockArg,
 			chanSizeArg,
-			metricsServerPort,
+			metricsServerEnabledArg,
+			metricsServerPortArg,
 			metricsCollectorEnabledArg,
 		)
 	})
@@ -179,7 +173,8 @@ func benchmarkReexecuteRange(
 	startBlock uint64,
 	endBlock uint64,
 	chanSize int,
-	metricsPort *uint64,
+	metricsServerEnabled bool,
+	metricsPort uint64,
 	metricsCollectorEnabled bool,
 ) {
 	r := require.New(b)
@@ -199,8 +194,8 @@ func benchmarkReexecuteRange(
 
 	log := tests.NewDefaultLogger("c-chain-reexecution")
 
-	if metricsPort != nil {
-		serverAddr := startServer(b, log, prefixGatherer, *metricsPort)
+	if metricsServerEnabled {
+		serverAddr := startServer(b, log, prefixGatherer, metricsPort)
 
 		if metricsCollectorEnabled {
 			startCollector(b, log, "c-chain-reexecution", labels, serverAddr)