TopolearnYou need to read charts you install and write charts for your own services.
helm create shop scaffolds a working chart:
Chart.yaml: metadata.apiVersion: v2,name,version(the chart's SemVer version, bump it on every chart change) andappVersion(the version of the app it deploys, informational). Alsotype(applicationorlibrary),dependencies,kubeVersionconstraints.values.yaml: defaults, documented with comments. This is the chart's public interface.templates/: manifests with Go template expressions. Every file is rendered; files starting with_(like_helpers.tpl) are not output and hold named templates.templates/NOTES.txt: rendered and printed after install, used for usage hints.charts/: packaged dependencies.values.schema.json(optional): JSON Schema that validates values..helmignore: files to leave out of the package.
helm template shop ./shop -f prod.yaml renders locally so you can read the YAML that would be applied, without a cluster. helm package ./shop creates shop-1.4.0.tgz.
Keep the chart close to the code it deploys (a chart/ or deploy/ directory) unless several services share a generic chart. Delete the scaffold's parts you don't use; a smaller chart is easier to maintain.
Example
helm create shop
tree shop
# shop/
# Chart.yaml values.yaml .helmignore charts/
# templates/ _helpers.tpl deployment.yaml service.yaml ingress.yaml
# hpa.yaml serviceaccount.yaml NOTES.txt tests/
cat shop/Chart.yaml
# apiVersion: v2
# name: shop
# type: application
# version: 0.1.0
# appVersion: "1.16.0"
helm template shop ./shop --set replicaCount=2 | grep -A2 'kind: Deployment'Remember
- version = chart version (bump on every change); appVersion = the app's
- Files starting with _ hold helpers and aren't rendered as manifests
- helm template renders locally for review
Watch out for
- Changing templates without bumping the chart version, so two different packages share one version.