e2e: Add image release test

[2opremio]

All tests until now run without using the registry scanner, so I thought it was about time to have an end-to-end test for image releases (which is a fundamental Flux feature)

We probably shouldn't depend on external registries (particularly on stefanprodan/podinfo since it is often updated) for tests. I plan to add an internal registry to the tests, but that will come later. If this test becomes too flakey I am happy to disable it until then. (I have added a local registry for Flux)

Addresses part of #2593 (adds a test covering fluxctl release).

TODO:

• Test automatic image releases
• Test HelmRelease image updates

[2opremio]

The bitnami images (e.g. bitnami/ghost ) from the flux-get-started repo have too many tags and we get rate-limited. This makes the test timeout.

I am considering to create and use a branch in flux-get-started guide, pointing to images from a registry local to the e2e tests. However, we would still need to load the redis/ghost/mongodb images in the local registry, which will take time.

Another option is to create a new example altogether, with tiny images. I wouldn't want to maintain that though.

@stefanprodan @hiddeco any other ideas?

[hiddeco]

Another option is to create a new example altogether, with tiny images. I wouldn't want to maintain that though.

We can build empty FROM scratch (or almost empty, given our label support) images in a loop in combination with a registry container and set the labels using --label 'date=$(date)', building ten images would take about a second and it requires no maintenance.

[2opremio]

Ah, it seems I can use an insecure registry mirror kubernetes-sigs/kind#110 (comment)

This will allow us to use the flux-started-guide unchanged.

However this implies changing the k8s node configuration, which I can do for Kind but won't work in general.

I think I can l live with that.

[2opremio]

More info https://kind.sigs.k8s.io/docs/user/local-registry/

[2opremio]

I think I can l live with that.

It's not ideal though, because I don't want to use Kind when working on the tests locally

[2opremio]

Here is an intermediate solution. Only make Flux use a local registry without changing the k8s configuration.

Kubernetes will pull images in whatever way it used to but Flux will query the local registry.

When spawning Kind we can also use a mirror.

In fact, if we don't change the get-started example we also need to modify Flux's configuration.

[2opremio]

I bit the bullet and I added a local registry to the test. Note that the registry is only used by Flux to scan images (and not by the cluster).

Adding an /etc/hosts entry for the registry allowed me to keep using https://github.com/fluxcd/flux-get-started as is.

[2opremio]

We may also want to change Kind's registry to a local one by leveraging #2752 (comment) , but that's for later.

[hiddeco]

Amazing work Fons, thanks 🥇