r/probe: added offset translator inconsistency error metric

Signed-off-by: Michał Maślanka <[email protected]>
(cherry picked from commit 3dc5470)

src/v/raft/consensus.cc

@@ -2253,6 +2253,7 @@ void consensus::validate_offset_translator_delta(
           "than expected: {}",
           meta,
           last_delta);
+        _probe->offset_translator_inconsistency_error();
     }
 }
 

src/v/raft/probe.cc

@@ -162,6 +162,12 @@ void probe::setup_metrics(const model::ntp& ntp) {
           [this] { return _full_heartbeat_requests; },
           sm::description("Number of full heartbeats sent by the leader"),
           labels),
+        sm::make_counter(
+          "offset_translator_inconsistency_errors",
+          [this] { return _offset_translator_inconsistency_error; },
+          sm::description("Number of append entries requests that failed the "
+                          "offset translator consistency check"),
+          labels),
       },
       {},
       {sm::shard_label, sm::label("partition")});

src/v/raft/probe.h

@@ -63,6 +63,9 @@ class probe {
 
     void full_heartbeat() { ++_full_heartbeat_requests; }
     void lw_heartbeat() { ++_lw_heartbeat_requests; }
+    void offset_translator_inconsistency_error() {
+        ++_offset_translator_inconsistency_error;
+    }
 
     void clear() {
         _metrics.clear();
@@ -89,7 +92,7 @@ class probe {
     uint64_t _recovery_request_error = 0;
     uint64_t _full_heartbeat_requests = 0;
     uint64_t _lw_heartbeat_requests = 0;
-
+    uint64_t _offset_translator_inconsistency_error = 0;
     metrics::internal_metric_groups _metrics;
     metrics::public_metric_groups _public_metrics;
 };