Skaffold & local docker daemon registry mirror

[iusetabs]

Expected behavior

• Skaffold should build images without hitting docker pull rate limits.

Actual behavior

• servicename: Error checking cache.
  getting hash for artifact "servicename": getting dependencies for "servicename": parsing ONBUILD instructions: retrieving image "php:8.0-apache": GET https://index.docker.io/v2/library/php/manifests/8.0-apache: TOOMANYREQUESTS: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit

Information

• Skaffold version: v1.35.2
• Operating system: Ubuntu 20.04
• Installed via: --> direct install via website ( For Linux x86_64 (amd64) )
• Output of skaffold config list:
  -- kube-context: [my AWS EKS cluster]
  -- default-repo: [my private docker repo]
  -- local-cluster: false
• Contents of skaffold.yaml:

<paste your skaffold.yaml here>
# Copyright 2021 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

apiVersion: skaffold/v2beta26
kind: Config
build:
  local:
    concurrency: 8
    tryImportMissing: true

  artifacts:
    # image tags are relative; to specify an image repo (e.g. GCR), you
    # must provide a "default repo" using one of the methods described
    # here:
    # https://skaffold.dev/docs/concepts/#image-repository-handling
    - image: servicename
      context: src/servicename
 
  tagPolicy:
    gitCommit: {}
deploy:
  kubectl:
    manifests:
      - ./kubernetes-manifests/**.yaml

Steps to reproduce the behavior

• In my local docker daemon, I have defined a registry mirror.
• Skaffold fails to build the application as it cannot pull "python:3.7-slim" or other images.
• However if I run docker pull python:3.7-slim, it uses my registry mirror and pulls it from there.
• My skaffold is configured to use the local docker daemon. Why is this error appearing with skaffold when docker pull, pulls the image successfully?
• Does skaffold ignore the docker daemon settings or is it trying to build on my EKS cluster?

[tejal29]

@iusetabs Skaffold relies on docker client lib to pull images. We don't do anything special and hence this should work out of the box.
That said, can you please provide us the docker daemon config filename and the contents?

[iosifnicolae2]

We're using kaniko, and we've configured registryMirror option but it seems that skaffold somehow uses index.docker.io when parsing ONBUILD instructions.

[oursland]

It appears that a skaffold dependency module is at fault, but several refer to index.docker.io so I am not sure which one.

I believe that prefixing the dockerhub images with docker.io/library/ will circumvent the automated insertion of index.docker.io/library/ that breaks the Docker's registry mirror configuration.

The issue appears to be with go-containerregistry and the lack of mirror support. See issue #1200.

[iusetabs]

@oursland Thx for the link to the issue, I've been spending some time looking into this again today. I'm not familiar with the source code of Skaffold at all, but I was digging into the code and once I hit the ConfigFile function at pkg/skaffold/docker/image.go:273 things got interesting 😉 I agree that this issue seems to be with the go-containerregistry library. Seems we must take this fight over there!

Even though this isn't a skaffold issue, I will have to remove skaffold from the pipeline I work with unless this can be fixed soon. This pull rate error is blocking my team😢 Unless somebody can suggest some hacky approach to quickly work around this issue 😉

[iusetabs]

After building skaffold locally and figuring out how it actually interacts with the go-containerregistry module, I was able to modify a local version of the go-containerregistry module and point skaffold at it. I added my mirror to the local go-containerregistry module and now it pulls through the mirror without any rate limit error.

However in order to get any change of this nature into a skaffold release, one needs to tweak the skaffold dependencies. go-containerregistry is on version 0.11 and skaffold is using version 0.8 of the module. When I tried updating the dependencies I got stuck with other dependency errors. So this might have unforeseen consequences and require changes in other parts of the skaffold codebase.

Also skaffold was particularly hard to debug, I had to put print statements in multiple places to see what was going on. It would be super nice to connect the IntelliJ Ultimate debugger to a debug version of the skaffold binary, has anybody any experience with that, maybe with Visual Code?

I will leave this issue open, as work will need to be done with Skaffold in order to leverage the docker mirrors whenever that feature is developed with go-containerregistry .

[ericzzzzzzz]

Needs to upgrade go-containerregistr version

[ericzzzzzzz]

go-containerregistry has been upgraded on HEAD, closing this out.