[Feature flag] Enable gitaly_praefect_use_yamux_configuration_for_gitaly
What
Enable the gitaly_praefect_use_yamux_configuration_for_gitaly
feature flag to decrease the window size used for Yamux streams between Praefect and Gitaly. This would prevent Praefect overbuffering responses if the clients are slow at consuming them as described in #4642 (closed).
Owners
- Team: Gitaly
- Most appropriate slack channel to reach out to:
#g_gitaly
- Best individual to reach out to: @samihiltunen
Expectations
What release does this feature occur in first?
What are we expecting to happen?
- Praefect uses less memory to buffer sidechannel traffic.
- No observable performance difference.
What might happen if this goes wrong?
- Praefect's network may get bottlenecked leading to increased latencies and timeouts.
What can we monitor to detect problems with this?
Apdex should remain stable.
Production: https://dashboards.gitlab.net/d/praefect-main/praefect-overview?orgId=1 \ Staging: https://dashboards.gitlab.net/d/praefect-main/praefect-overview?orgId=1&var-PROMETHEUS_DS=Global&var-environment=gstg&var-stage=main
Roll Out Steps
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Enable on staging -
Is the required code deployed on staging? (howto) -
Enable on staging (howto) -
Add featureflagstaging to this issue (howto) -
Test on staging (howto) -
Verify the feature flag was used by checking Prometheus metric gitaly_feature_flag_checks_total
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Enable on production -
Is the required code deployed on production? (howto) -
Progressively enable in production (howto) -
Add featureflagproduction to this issue -
Verify the feature flag was used by checking Prometheus metric gitaly_feature_flag_checks_total
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Default-enable the feature flag (optional, only required if backwards-compatibility concerns exist) -
Wait for release containg default-disabled feature flag. -
Change the feature flag to default-enabled (howto) -
Wait for release containing default-enabled feature flag.
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Remove feature flag
Please refer to the documentation of feature flags for further information.
Edited by Sami Hiltunen