Kops uses the Kubernetes API machinery. It is well designed, and very powerful, but you have to jump through some hoops to use it.
Recommended reading: kubernetes API changes doc
The kops APIs live in pkg/apis/kops, both in
that directory directly (the unversioned API) and in the versioned subdirectories (v1alpha1
, v1alpha2
).
You will need a few tools from kubernetes (these will likely be moved to a shared repo soon):
go get k8s.io/kubernetes
cd ${GOPATH}/src/k8s.io/kubernetes
git checkout master
git pull
Then you can run make apimachinery && make
to update the generated API machinery code (conversion functions). Note
that make apimachinery
(currently) only updates the autogenerated code; it does not trigger a rebuild, hence the
need for && make
.
The most common task you will do will be to add a new field. This is relatively straightforward, because it is backwards compatible (you have to make sure that the field is optional).
- Add the field to pkg/apis/kops, and then also to each versioned copy: pkg/apis/kops/v1alpha1, pkg/apis/kops/v1alpah2, etc
- Run the apimachinery update as above (
make apimachinery && make
) - You likely want to update the validation logic
- You likely want to update the defaulting logic
Currently, the apimachinery code we check in is relatively stable. However, when the generated code is large, it is often considered good manners to your code reviewer to split a PR into multiple commits: one with the actual changes, and then a second commit with the autogenerated code.