Difference between revisions of "Kubernetes/Helm"
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= Known workarounds = | = Known workarounds = | ||
== Invalid spec selector after upgrading helm template == | == Invalid spec selector after upgrading helm template == | ||
This is caused by dynamic labels in <code>selector</code> as of Kubernetes version X field is immutable. | |||
* [https://stackoverflow.com/questions/53998259/invalid-spec-selector-after-upgrading-helm-template Invalid spec selector after upgrading helm template] StackOverflow | * [https://stackoverflow.com/questions/53998259/invalid-spec-selector-after-upgrading-helm-template Invalid spec selector after upgrading helm template] StackOverflow | ||
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kubectl patch deployments my-release --type=json -p='[{"op": "remove", "path": "/spec/selector/matchLabels/chart"}]' | kubectl patch deployments my-release --type=json -p='[{"op": "remove", "path": "/spec/selector/matchLabels/chart"}]' | ||
</source> | </source> | ||
= Resources = | = Resources = | ||
* [https://helm.sh/docs/intro/using_helm/ Using Helm Guide] | * [https://helm.sh/docs/intro/using_helm/ Using Helm Guide] |
Revision as of 09:06, 29 April 2020
Note: This content refers to helm3 as authored in April, 2020.
Install
LATEST=$(curl --silent "https://api.github.com/repos/helm/helm/releases/latest" | jq -r .tag_name) curl -LO https://get.helm.sh/helm-${LATEST}-linux-amd64.tar.gz tar xzvf helm-${LATEST}-linux-amd64.tar.gz sudo install linux-amd64/helm /usr/local/bin/helm
Operations
Helm command
helm version --short # --> v3.1.3+g0a9a9a8 helm [command] -h # get help create|env|get|history|install|lint|list|plugin|rollback|show|status|template|uninstall|upgrade # Flags: # --kube-context string -name of the kubeconfig context to use # --kubeconfig string -path to the kubeconfig file # -n, --namespace string
Operations
# Add repo helm repo add stable https://kubernetes-charts.storage.googleapis.com/ helm repo update # Make sure we get the latest list of charts helm search repo stable/jenkins # Set kubectl context # Helm3 bug:does may not respect '--namespace' flag, so set default namespace kubectl create ns jenkins kubectl config set-context $(kubectl config current-context) --namespace=jenkins # Install release helm install [NAME] [CHART] [flags] helm install jenkins-ci stable/jenkins # release name: jenkins-ci helm install jenkins-ci ./jenkins-2.192.1.tgz --set service.type=NodePort # install from a tarball package helm install stable/mysql --generate-name # release name will be generated # Get information about releases helm ls -A # show a list of all deployed releases -A --all-namespaces NAME NAMESPACE REVISION UPDATED STATUS CHART APP VERSION jenkins-ci jenkins 1 2020-04-25 15:.. deployed jenkins-1.17.2 lts helm get all -n jenkins jenkins-ci # all|hooks|manifest|notes|values(user defined values) # Uninstall release helm uninstall jenkins-ci --namespace jenkins
- Rollback
$> helm rollback <RELEASE> [REVISION] [flags] $> helm rollback diy 2 --dry-run # <RELEASE> = diy $> time helm rollback diy 2 --wait # --wait until all Pods, PVCs... are in a ready state before marking the release as successful. # It will wait for as long as --timeout # Note: Each rollback increments REVISION with +1 $> helm history diy REVISION UPDATED STATUS CHART APP VERSION DESCRIPTION 1 Mon Apr 27 10:39:38 2020 superseded diy-0.1.0 6.4.2 Install complete 2 Mon Apr 27 12:24:54 2020 superseded diy-0.1.0 6.4.2 Upgrade complete 3 Mon Apr 27 16:22:34 2020 superseded diy-0.1.0 6.4.2 Upgrade complete 4 Mon Apr 27 16:35:31 2020 deployed diy-0.1.0 6.4.2 Rollback to 2
- Jenkins chart post install instructions or
get notes
commands
helm get notes -n jenkins jenkins-ci
NAME: jenkins-ci LAST DEPLOYED: Sat Apr 25 15:33:36 2020 NAMESPACE: jenkins STATUS: deployed REVISION: 1 NOTES: 1. Get your 'admin' user password by running: printf $(kubectl get secret --namespace jenkins jenkins-ci -o jsonpath="{.data.jenkins-admin-password}" | base64 --decode);echo 2. Get the Jenkins URL to visit by running these commands in the same shell: export POD_NAME=$(kubectl get pods --namespace jenkins -l "app.kubernetes.io/component=jenkins-master" -l "app.kubernetes.io/instance=jenkins-ci" -o jsonpath="{.items[0].metadata.name}") echo http://127.0.0.1:8080 kubectl --namespace jenkins port-forward $POD_NAME 8080:8080 3. Login with the password from step 1 and the username: admin For more information on running Jenkins on Kubernetes, visit: https://cloud.google.com/solutions/jenkins-on-container-engine
Create a chart
Note: Check The chart file structure as the helm create NAME
does not include all optional files you may use
helm version --short # -> v3.1.3+g0a9a9a8 helm create diy # diy = [NAME] # this creates standard file tree not all optional files are included $> tree diy diy ├── charts # any charts upon which this chart depends ├── Chart.yaml ├── templates # no rigid naming pattern, recommended .yaml for YAML files and .tpl for helper | | # all files here will be sent through the template engine │ ├── deployment.yaml │ ├── _helpers.tpl # template helpers that you can re-use throughout the chart │ ├── ingress.yaml │ ├── NOTES.txt # Optional. “help text” for your chart, displayed after installation │ ├── serviceaccount.yaml │ ├── service.yaml │ └── tests │ └── test-connection.yaml └── values.yaml # default configuration values for this chart helm template diy | bat -l yaml --style=plain # display rendered yaml manifests kubectl create ns diy helm install ./diy --generate-name -n diy # Generated name # ____NAME______ # podName : pod/diy-1587926286-866d97bb75-vskns # serviceName : service/diy-1587926286 # deploymentName: deployment.extensions/diy-1587926286 # NAME TYPE # secret/sh.helm.release.v1.diy-1587926286.v1 helm.sh/release.v1 helm install foo ./diy -n diy # Custom name # _NAME__ # podName : pod/foo-diy-6fd79d9bbd-nh5hl # serviceName : service/foo-diy # deploymentName: deployment.extensions/foo-diy # NAME TYPE # secret/sh.helm.release.v1.foo.v1 helm.sh/release.v1 helm list -n diy NAME NAMESPACE REVISION UPDATED STATUS CHART APP VERSION diy-1587926286 diy 1 2020-04-26 19:38... deployed diy-0.1.0 1.16.0 foo diy 1 2020-04-26 20:02... deployed diy-0.1.0 1.16.0
Template
Everything in templates/
goes through templating engine before being rendered. Basic template might look like below:
# TEMPLATE ---> RENDER ---> DEPLOYED # # helm install mychart ./mychart -n mychart # cat templates/configmap.yaml # helm template mychart/ # kubectl -n mychart get cm mychart-configmap -oyaml | apiVersion: v1 | apiVersion: v1 | apiVersion: v1 | kind: ConfigMap | kind: ConfigMap | kind: ConfigMap | metadata: -> | metadata: --> | metadata: | name: {{ .Release.Name }}-configmap | name: RELEASE-NAME-configmap | name: mychart-configmap | data: | data: | data: | myvalue: "Hello World Piotrek" | myvalue: "Hello World Piotrek" | myvalue: Hello World Piotrek
Note: In kubectl get cm
above creationTimestamp:
and selfLink:
data yaml keys have been not included for clarity of side-by-side comparison.
- References
- Buildin objects helm.sh
- Best Practicies helm.sh
- Math Functions gohugo.io
- Go Template package golang.org
Text and spaces
Note: Details about whitespace control you can find in Flow Control in Controlling Whitespace section.
If an action's left delimiter (by default "{{") is followed immediately by a minus sign and ASCII space character ("{{- "), all trailing white space is trimmed from the immediately preceding text. Similarly, if the right delimiter ("}}") is preceded by a space and minus sign (" -}}"), all leading white space is trimmed from the immediately following text. In these trim markers, the ASCII space must be present; "{{-3}}" parses as an action containing the number -3.
For instance, when executing the template whose source is
"{{23 -}} < {{- 45}}" // the generated output would be "23<45"
For this trimming, the definition of white space characters is the same as in Go: space, horizontal tab, carriage return, and newline.
Package and push charts to OCI registry
- push-helm-charts-to-amazon-ecr
- Giving your Charts a Home in Docker Registry
- [ECR: Allow for alternate mediaTypes] AWS ECR
Known workarounds
Invalid spec selector after upgrading helm template
This is caused by dynamic labels in selector
as of Kubernetes version X field is immutable.
- Invalid spec selector after upgrading helm template StackOverflow
Steps to before upgrade without need of uninstalling charts:
$ kubectl delete statefulsets.apps --cascade=false my-release # Edit the deployment: kubectl patch deployments my-release --type=json -p='[{"op": "remove", "path": "/spec/selector/matchLabels/chart"}]'