onechart/website/docs/examples/feature-branch-deploys.md

Feature branch deploys in large part is a templating question:

• Names should be unique to avoid collision between application instances
• Names should follow some convention
• It's driven by CI, and git branch name is a typical input parameter

Avoiding name collisions

With OneChart, you can drive the naming of most resources by setting a unique release name. Release name is unique in Helm too, so it makes it a good tool to drive resource names.

One good practice can be to add a -$BRANCH suffix to the feature branch instance:

helm template my-release-my-branch onechart/onechart -f values.yaml

Avoiding domain name collision

The release name will make all Kubernetes objects unique, but the domain name configuration remains static:

image:
  repository: nginx
  tag: 1.19.3

ingress:
  annotations:
    kubernetes.io/ingress.class: nginx
  host: my-release.mycompany.com

helm template my-release-my-branch onechart/onechart -f values.yaml

The ingress.host name should also be dynamic to avoid the collision:

helm template my-release-my-branch onechart/onechart\
  -f values.yaml \
  --set ingress.host=my-release-my-branch.mycompany.com

CI

In CI the above command needs to be templated:

helm template my-release-$BRANCH onechart/onechart\
  -f values.yaml \
  --set ingress.host=my-release-$BRANCH.mycompany.com

where $BRANCH is a built-in CI variable.