Kustomize

Kustomize introduces a template-free way to customize application configuration that simplifies the use of off-the-shelf applications. Now, built into kubectl as apply -k.

If you have a directory with a couple of kubernetes yaml files and you want to make an edit to one without committing a change, you can add a kustomization.yaml to make a change to one of the config files.

• kustomize reads plain kubernetes yaml
• you can kubectl appply that yaml without kustomize
• you can drop in a kustomize file to make adjustments

things that you can / want to customize between environments

• change image tags
• change image tags
• change cpu memory etc.
• change policies and network

overlays

• use case separate dev / staging / production
• example
  • dev: runs image hourly build
  • staging runs image passed QA, 1% of prod traffic
  • production: has fixed version, big replicas and big cpu
• kustomization
  • change prefixes
  • add specific tags to resources
• folder structure: base and overlays directories
  • e.g. replica_count.yaml and cpu_count.yaml to change and possible reuse these

references

• Kubernetes