Difference between revisions of "Kubernetes/Helm"
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* [https://gohugo.io/functions/math/ Math Functions] gohugo.io | * [https://gohugo.io/functions/math/ Math Functions] gohugo.io | ||
* [https://golang.org/pkg/text/template/ Go Template package] golang.org | * [https://golang.org/pkg/text/template/ Go Template package] golang.org | ||
== Text and spaces == | |||
If an action's left delimiter (by default <nowiki>"{{")</nowiki> is followed immediately by a minus sign and ASCII space character <nowiki>("{{- ")</nowiki>, all trailing white space is trimmed from the immediately preceding text. Similarly, if the right delimiter <nowiki>("}}")</nowiki> is preceded by a space and minus sign <nowiki>(" -}}")</nowiki>, all leading white space is trimmed from the immediately following text. In these trim markers, the ASCII space must be present; <nowiki>"{{-3}}"</nowiki> parses as an action containing the number -3. | |||
For instance, when executing the template whose source is | |||
<source lang=go> | |||
"{{23 -}} < {{- 45}}" | |||
// the generated output would be | |||
"23<45" | |||
</source> | |||
For this trimming, the definition of white space characters is the same as in Go: space, horizontal tab, carriage return, and newline. | |||
= 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 17:19, 27 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 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
- Jenkins chart post install instructions or
get notescommands
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
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.