feat(helm): add cluster mode values for Dragonfly chart by VedantMadane · Pull Request #7123 · dragonflydb/dragonfly

VedantMadane · 2026-04-12T11:49:48Z

Summary

Adds predefined Helm values for Redis-compatible cluster mode so users can enable Dragonfly cluster flags without hand-writing extraArgs.

Changes

values.yaml: new cluster.mode (maps to --cluster_mode) and cluster.experimentalShardBySlot (maps to --experimental_cluster_shard_by_slot=true when mode is set)
templates/_pod.tpl: append the corresponding CLI args when cluster.mode is non-empty

Notes

Valid cluster.mode values match the Dragonfly flag: emulated, yes, or empty to leave cluster mode disabled. See server cluster_support.cc for flag semantics.

Fixes #3861

Copilot

Pull request overview

Adds first-class Helm values for enabling Dragonfly’s Redis-compatible cluster mode, so users don’t need to manually supply extraArgs for common cluster flags.

Changes:

Introduces cluster.mode and cluster.experimentalShardBySlot in chart values.yaml.
Updates the pod template to append --cluster_mode=... and optionally --experimental_cluster_shard_by_slot=true based on those values.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
contrib/charts/dragonfly/values.yaml	Adds documented `cluster.*` values for cluster mode and slot-based sharding.
contrib/charts/dragonfly/templates/_pod.tpl	Renders the corresponding Dragonfly CLI flags when `cluster.mode` is set.

Copilot · 2026-04-12T11:52:17Z

 extraArgs: []

+cluster:
+  # -- Redis cluster protocol mode passed to Dragonfly as --cluster_mode. Use "emulated", "yes", or leave empty to disable cluster mode.


.Values.cluster.mode is documented as accepting "yes", but in YAML users often write mode: yes (unquoted), which parses as a boolean and can either render --cluster_mode=true or even break the ne comparison during templating. Consider updating the docs here to explicitly require quoting (e.g. mode: "yes") and/or changing the chart to coerce the value to string before comparing/printing.

Suggested change

# -- Redis cluster protocol mode passed to Dragonfly as --cluster_mode. Use "emulated", "yes", or leave empty to disable cluster mode.

# -- Redis cluster protocol mode passed to Dragonfly as --cluster_mode.

# -- This value must be quoted because YAML may parse unquoted `yes` as a boolean.

# -- Use `mode: "emulated"` or `mode: "yes"`, or leave empty to disable cluster mode.

Copilot · 2026-04-12T11:52:18Z

+    {{- if ne (.mode | default "") "" }}
+      - "--cluster_mode={{ .mode }}"
+    {{- end }}
+    {{- if and (ne (.mode | default "") "") .experimentalShardBySlot }}


The ne (.mode | default "") "" check and --cluster_mode={{ .mode }} assume .mode is a string; if a user sets cluster.mode: yes without quotes, Helm may parse it as boolean and this comparison can fail (or render --cluster_mode=true). Coerce .mode to a string (and ideally validate allowed values) before comparing/using it.

Suggested change

{{- if ne (.mode | default "") "" }}

- "--cluster_mode={{ .mode }}"

{{- end }}

{{- if and (ne (.mode | default "") "") .experimentalShardBySlot }}

{{- $clusterMode := printf "%v" (.mode | default "") }}

{{- if ne $clusterMode "" }}

- "--cluster_mode={{ $clusterMode }}"

{{- end }}

{{- if and (ne $clusterMode "") .experimentalShardBySlot }}

romange · 2026-04-12T11:54:35Z

augment review

Abhra303

Thanks for the PR, see some comments.

Abhra303 · 2026-04-13T05:56:17Z

 {{- end }}
 {{- end }}
-{{- end }}
+{{- end }}


add back newline at the end of the file

Done, restored the trailing newline.

Abhra303 · 2026-04-13T06:30:37Z


+cluster:
+  # -- Redis cluster protocol mode passed to Dragonfly as --cluster_mode.
+  # -- Use "emulated" or "yes" (must be quoted in YAML to avoid boolean coercion).


If the user passes unquoted yes, the template won't validate this and and df will fail. I suggest to either validate the input and fail if the input is not string or support boolean yes as well. As you're adding a cluster specific fields, it makes sense to support boolean yes as well.

for boolean yes support :

{{- with .Values.cluster }} {{- $modeRaw := .mode | default "" }} {{- $clusterMode := "" }} {{- if kindIs "bool" $modeRaw }} {{- if $modeRaw }}{{- $clusterMode = "yes" }}{{- end }} {{- else }} {{- $clusterMode = $modeRaw | toString }} {{- end }} {{- if ne $clusterMode "" }} - "--cluster_mode={{ $clusterMode }}" {{- end }}

Or, if you want to validate:

{{- with .Values.cluster }} {{- $modeRaw := .mode | default "" }} {{- if kindIs "bool" $modeRaw }} {{- fail "cluster.mode must be a quoted string — use '\"yes\"' or '\"emulated\"' (unquoted 'yes' is parsed as a YAML boolean)" }} {{- end }} {{- $clusterMode := $modeRaw | toString }}

Good call, went with the boolean coercion approach. If .mode is a bool (unquoted yes in YAML), it now maps to the string "yes". Updated the values.yaml comment to document that behavior too.

Abhra303 · 2026-04-13T06:33:34Z

Also wondering we have extraArgs which should be enough to add cluster mode values. Why do you think it is not viable to set cluster mode via extraArgs?

Abhra303

Looks good.

romange · 2026-04-13T16:30:10Z

@VedantMadane please squash and sign your commits. See this for details:

dragonfly/CONTRIBUTING.md

Lines 35 to 53 in 31a8fd3

    
           ### Signing commits with GPG 
        
           We require all commits to be signed with a GPG key. To set this up: 
        
           ```sh 
        
           # List your GPG keys 
        
           gpg --list-secret-keys --keyid-format=long 
        
           # If you don't have a key, create one 
        
           gpg --full-generate-key 
        
           # Configure git to use your GPG key for signing (replace KEY_ID with your actual key) 
        
           git config --global user.signingkey KEY_ID 
        
           # Enable automatic signing for all commits 
        
           git config --global commit.gpgsign true 
        
           ``` 
        
           All commits must be signed (this is enforced by the pre-commit hooks). When you commit, you'll be prompted for your GPG passphrase if it's not cached.

VedantMadane · 2026-04-15T14:59:44Z

You raise a fair point about extraArgs. The difference is that dedicated cluster.mode values let the chart validate input (the boolean coercion fix), set sensible defaults for related settings (like replica count), and keep the values.yaml self-documenting for users who helm show values the chart. extraArgs would work but pushes validation onto the user.

That said, if you prefer the extraArgs-only approach, I am happy to simplify the PR to just the documentation changes. Let me know which direction you would like.

Regarding squash and sign-off: will do that now.

Add dedicated cluster.mode and cluster.node_count values to the Helm chart so users can enable cluster mode without resorting to extraArgs. The template coerces unquoted YAML booleans (yes/no) to the string Dragonfly expects, preventing silent misconfiguration. Fixes dragonflydb#3861 Signed-off-by: Vedant Madane <vedant.madane@gmail.com>

Copilot AI review requested due to automatic review settings April 12, 2026 11:49

Copilot started reviewing on behalf of VedantMadane April 12, 2026 11:50 View session

Copilot AI reviewed Apr 12, 2026

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Abhra303 suggested changes Apr 13, 2026

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romange requested a review from Abhra303 April 13, 2026 13:06

Abhra303 approved these changes Apr 13, 2026

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romange approved these changes Apr 13, 2026

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VedantMadane force-pushed the feat/helm-cluster-mode-3861 branch from 2817e38 to da26108 Compare April 15, 2026 15:01

Vedant Madane and others added 3 commits April 15, 2026 15:30

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VedantMadane commented Apr 12, 2026 •

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