kubernetes/ingress-nginx

Zero downtime upgrade

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#6,928 opened on Mar 4, 2021

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Description

Docs (https://github.com/kubernetes/ingress-nginx/tree/master/charts/ingress-nginx#upgrading-with-zero-downtime-in-production) are mentioning that by default during an upgrade there is a service interruption caused by pods being restarted, and another article is linked with explanation how one can fix that.

But when looking at values.yml I can see both terminationGracePerios and preStop hook is set correctly in order to drain connections.

https://github.com/kubernetes/ingress-nginx/blob/a7fb791132a0dee285b47d0041f4f9acf1e7cff8/charts/ingress-nginx/values.yaml#L237

https://github.com/kubernetes/ingress-nginx/blob/a7fb791132a0dee285b47d0041f4f9acf1e7cff8/charts/ingress-nginx/values.yaml#L583-L587

Is the documentation a little bit outdated or there is something else that I should set to get near zero downtime upgrades?

Contributor guide

Tech stack
gokubernetesdocker
Domain
devopsinfrastructurecloud
Issue type
documentation
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
basic kubernetes knowledgehelm chart configurationunderstanding of pod lifecycle hooks
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Investigate the helm chart values for terminationGracePeriodSeconds and preStop hook in ingress nginx (see values.yaml lines 237, 583-587). Compare with the linked documentation on zero downtime upgrades. Determine if the documentation is outdated or if additional configuration is needed. Check the referenced article for zero downtime strategies and test the behavior during a rolling update. Consider updating the documentation or values if inconsistencies are found.