On-Call Helm3

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Cheatsheet to help install/upgrade/rollback helm charts.

Repo Chart

Note chart release name can be different from chart name.

Add and sync helm repo:

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# add helm repo if needs
helm repo add <repo name> <repo URL> \
--username xx \
--password xx

# sync helm repo
# you need to run this if any chart version updated
helm repo update

# list helm repos
helm repo list

# search
# -l: lish all verions
# --version: regexp to filter version
helm search repo <chart name> [-l] [--version ^1.0.0]
# CHART VERSION is for chart upgrade or install
# show latest VERSION here
NAME           CHART VERSION	APP VERSION	DESCRIPTION
xxx            2.1.0       	    3.3.2     	xxxxxx

View helm installed chart:

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# list installed charts
helm list [-n <namespace>]

# check chart history
# xxx-1.0.1: xxx is chart name, 1.0.1 is chart version
helm history <release name> [-n <namespace>]
REVISION	UPDATED                 	STATUS    	CHART                	APP VERSION	DESCRIPTION
1       	Mon Oct 11 19:41:41 2021	superseded	xxx-1.0.1   	1.8.3      	Install complete
2       	Mon Oct 18 17:39:37 2021	superseded	xxx-1.0.2   	1.8.3      	Upgrade complete
3       	Mon Oct 18 17:41:29 2021	superseded	xxx-1.0.1   	1.8.3      	Rollback to 1
4       	Mon Oct 18 17:44:21 2021	superseded	xxx-1.0.1   	1.8.3      	Upgrade complete
5       	Mon Oct 18 17:55:28 2021	deployed  	xxx-1.0.2-66	1.8.3      	Upgrade complete

# check chart installed status/output
helm status <release name> [-n <namespace>]

Install or Upgrade chart:

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# get current chart values
# edit if necessary
helm get values <release name> [-n <namespace>] > values.yaml

# upgrade with specified version and values.yaml
# -f: specify vaules if necessary, if not, will reuse the existing as helm get values output
# where to get version: helm search
helm install/upgrade <release name> [repo/chart] [-n <namespace>] --version <version> [-f values.yaml]
# helm upgrade example gcloud-helm/example --version 1.0.1 -f values.yaml
# if run helm history, will displayed as xxx-1.0.3 in CHART column
# 1.0.3 is the --version value
# note that if the version format is 1.0.3.19, have to convert to 1.0.3-19 in command

# see upgrade result
helm history <release name> [-n <namespace>]

Rollback chart:

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# REVISION is from helm history, see above
# if REVISION is ignored, rollback to previous release
helm rollback <release name> [-n <namespace>] [REVISION]
# note that rollback will also rollback the values

# see rollback result
helm history <release name> [-n <namespace>]

Uninstall and install chart:

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# --keep-history if necessary
# in case need to rollback
helm uninstall <release name> [--keep-history] [-n <namespace>]

Download chart package to local:

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# helm-repo is repo name from "helm repo list"
# example is chart name from that repo
# --version specify version of the chart
helm pull helm-repo/example --version 1.0.1

Local Chart

For developing purpose, we can install directly from local chart folder.

You need to create Chart.yaml which contains chart version, appVersion, etc.

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# without k8s cluster
# rendering template and check
# --debug: verbose output
helm template [--values <path to yaml file>] \
[--debug] \
<path to chart folder> \
| less

# in k8s cluster
# real helm install but without commit
# can generate a release name as [release]
helm install [release name] <path to chart folder> \
[-n <namespace>] \
--dry-run \
--debug 2>&1 \
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# real install
helm install [release name] <path to chart folder>

# uninstall
helm uninstall <release name> [-n <namespace>]
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