Use constructor for ecrProvider
Rename package to "credentials" like golint requests
Don't wrap the lazy provider with a caching provider
Add immedita compile-time interface conformance checks for the interfaces
Added comments
This is step two. We now create long-lived, lazy ECR providers in all regions.
When first used, they will create the actual ECR providers doing the work
behind the scenes, namely talking to ECR in the region where the image lives,
rather than the one our instance is running in.
Also:
- moved the list of AWS regions out of the AWS cloudprovider and into the
credentialprovider, then exported it from there.
- improved logging
Behold, running in us-east-1:
```
aws_credentials.go:127] Creating ecrProvider for us-west-2
aws_credentials.go:63] AWS request: ecr:GetAuthorizationToken in us-west-2
aws_credentials.go:217] Adding credentials for user AWS in us-west-2
Successfully pulled image 123456789012.dkr.ecr.us-west-2.amazonaws.com/test:latest"
```
*"One small step for a pod, one giant leap for Kube-kind."*
This is step one for cross-region ECR support and has no visible effects yet.
I'm not crazy about the name LazyProvide. Perhaps the interface method could
remain like that and the package method of the same name could become
LateBind(). I still don't understand why the credential provider has a
DockerConfigEntry that has the same fields but is distinct from
docker.AuthConfiguration. I had to write a converter now that we do that in
more than one place.
In step two, I'll add another intermediate, lazy provider for each AWS region,
whose empty LazyAuthConfiguration will have a refresh time of months or years.
Behind the scenes, it'll use an actual ecrProvider with the usual ~12 hour
credentials, that will get created (and later refreshed) only when kubelet is
attempting to pull an image. If we simply turned ecrProvider directly into a
lazy provider, we would bypass all the caching and get new credentials for
each image pulled.
A lot of packages use StringSet, but they don't use anything else from
the util package. Moving StringSet into another package will shrink
their dependency trees significantly.
With this change, you can add --google_json_key=/path/to/key.json to the DAEMON_ARGS of the kubelet, e.g.
nano /etc/default/kubelet
... # Add the flag
service kubelet restart
With this setting, minions will be able to authenticate with gcr.io repositories nearly as smoothly as if K8s were running on GCE.
NOTE: This private key can be used to access most project resources, consider dropping the service account created through this flow to a project READER, or restricting its access to just the GCS bucket containing the container images.
Docker's logic for resolving credentials from .dockercfg accepts two kinds of matches:
1. an exact match between the dockercfg entry and the image prefix
2. a hostname match between the dockercfg entry and the image prefix
This change implements the latter, which permits the docker client to take .dockercfg entries of the form:
https://quay.io/v1/
and use them for images of the form:
quay.io/foo/bar
even though they are not a prefix-match.
In particular, a few of the utilities used within the credentialprovider had the pattern:
glog.Errorf("while blah %s: %v", s, err)
return nil, err
This change propagates those error message and puts the burden of logging on the caller.
In particular, this allows us to squelch all output during kubelet startup when we are detecting whether certain credentialprovider plugins should even be enabled.
Fixes: https://github.com/GoogleCloudPlatform/kubernetes/issues/2673
Vishnu kannan