Manage Helm chart repositories using custom resources

[hiddeco]

Edit: This has been implemented in helm-controller the successor of helm-operator, please see https://toolkit.fluxcd.io/

In #124 and #141 boilerplate was added to manage Helm chart repositories for Helm v2 and v3. The current implementation is however extremely limited and still requires the user to provide (and manage) a repository index file.

It would be more user friendly, and declarative, to introduce a new custom resource definition called i.e. HelmChartRepository to make it possible to manage the repositories using Kubernetes resources.

[stefanprodan]

Proposal: decoupling chart/git repositories from HelmReleases

Features:

• a release references a chart source (can be helm chart repo or git repo)
• a chart source references a secret (helm chart repo basic auth, git https basic auth or git ssh key)
• a release can reference a chart source defined in a different namespace so that cluster admins can manage the sources in a restricted namespace
• by running multiple helm-op instances we can restrict with RBAC what sources an operator instance can use
• by allowing cross-namespace references, we can avoid duplicating the source definitions (e.g. stable) for each namespace

Chart repository with basic auth:

apiVersion: helm.fluxcd.io/v1
kind: ChartRepository
metadata:
  name: azurecr
  namespace: fluxcd
spec:
  url: https://<repository>.azurecr.io/helm/v1/repo #required
  secretRef: #optional
    name: azurecr-auth #required

Chart repository basic auth secret format:

apiVersion: v1
kind: Secret
metadata:
  name: azurecr-auth
  namespace: fluxcd
type: Opaque
data:
  username: <BASE64> #required
  password: <BASE64> #required
  caFile: <BASE64> #optional (path to file inside the helm-op container)
  certFile: <BASE64> #optional (path to file inside the helm-op container)
  keyFile: <BASE64> #optional (path to file inside the helm-op container)

Reference ChartRepository in HelmRelease with cross-namespace support:

apiVersion: helm.fluxcd.io/v2
kind: HelmRelease
metadata:
  name: podinfo
  namespace: demo
spec:
  chart:
    name: podinfo #required (either name or path)
    version: 3.1.0 #required (when using chartRepositoryRef)
    chartRepositoryRef: #required (either chartRepositoryRef or gitRepositoryRef) 
      name: azurecr #required
      namespace: fluxcd #optional (defaults to HelmRelease ns)

HTTPS Git repository with basic auth:

apiVersion: helm.fluxcd.io/v1
kind: GitRepository
metadata:
  name: git-https-repo
  namespace: fluxcd
spec:
  url: https://github.com/myrepo.git #required (either url or git) 
  ref: master #optional (defaults to master)
  secretRef: #optional
    name: git-basic-auth #required

HTTPS Git repository basic auth secret format:

apiVersion: v1
kind: Secret
metadata:
  name: git-basic-auth
  namespace: fluxcd
type: Opaque
data:
  username: <BASE64> #required
  password: <BASE64> #required

Git repository with SSH auth:

apiVersion: helm.fluxcd.io/v1
kind: GitRepository
metadata:
  name: git-ssh-repo
  namespace: fluxcd
spec:
  git: ssh://git@gitsrv/git-server/repos/cluster.git #required (either url or git) 
  ref: master #optional (defaults to master)
  secretRef: #optional
    name: git-ssh-key #required

Git repository SSH secret format:

apiVersion: v1
kind: Secret
metadata:
  name: git-ssh-key
  namespace: fluxcd
type: Opaque
data:
  identity: <BASE64> #required

Reference GitRepository in HelmRelease with cross-namespace support:

apiVersion: helm.fluxcd.io/v2
kind: HelmRelease
metadata:
  name: podinfo
  namespace: demo
spec:
  chart:
    path: charts/podinfo #required (either name or path)
    gitRepositoryRef: #required (either chartRepositoryRef or gitRepositoryRef) 
      name: https-repo
      namespace: fluxcd #optional (defaults to HelmRelease ns)

HelmRelease v2

The above changes would require a new major release of the HelmRelease CRD.

Chart repo changes:

kind: HelmRelease
spec:
  chart:
    repository: # replaced with chartRepositoryRef
    name: # no changes 
    version: # no changes

Git repo changes:

kind: HelmRelease
spec:
  chart:
    git: # replaced with gitRepositoryRef
    ref: master # moved to GitRepository.spec.ref
    path: charts/ghost # no changes

[hiddeco]

@stefanprodan can you extend the examples to show how one would provide custom certificates for the ChartRepository kind?

[stefanprodan]

@hiddeco I've added the cert fields to the secret as file paths.

[oleksandrsemak]

Hello, as I understood basic HTTPS implemented only for git? not for regular private char repo?
when I try using private chart repo and HelmRelease with secretRef I get: not a valid chart repository or cannot be reached: Failed to fetch 401 Unauthorized

[seaneagan]

For CRD naming:

• should there be consistency with HelmRelease in terms of the Helm prefix?
• the term Repository means something different in ChartRepository and GitRepository. What about using a Source suffix instead?

Taking those into consideration, what about something like: HelmRepoSource, HelmGitSource, and then in the future if helm registry catches on, HelmRegistrySource? Referred to as:

  chart:
    path: ...
    gitSourceRef:
      namespace: ...
      name: ...

  chart:
    name: ...
    version: ...
    repoSourceRef:
      namespace: ...
      name: ...

  chart:
    name: ...
    # future extension
    registrySourceRef:
      namespace: ...
      name: ...

Relating this to values / valuesFrom, there is a tradeoff to having reference data in separate CRs, namely that changes in the reference CRs won't be automatically reconciled (see #151). Perhaps similarly to values there could still be an ability to define source inline as well:

  chart:
    name: ...
    version: ...
    # inline source
    gitSource:  # or repoSource or registrySource (same content as reference CR specs)
      git: ssh://git@gitsrv/git-server/repos/cluster.git #required (either url or git) 
      ref: master #optional (defaults to master)
      secretRef: #optional
        name: git-ssh-key #required

[stefanprodan]

Implemented in helm-controller, see https://toolkit.fluxcd.io/guides/helmreleases/