Docker model runner container does not sync changes to config.json; requires restart (engine only)

[amisevsk]

Description

Info: I am using Linux, Docker Engine-only, and no credential helper; I haven't tried any other use cases (I imagine a credential helper makes this trickier).

It appears that the docker-model-runner container takes its config.json from the local system on startup. However, this file is not synced from the system while the model-runner is running, meaning any docker login actions will not be reflected into the model runner, and any docker model push that requires the new auth will fail with a standard "insufficient scope". This is confusing as it suggests that some additional configuration on the registry side is required (regular pushes succeed).

Restarting the model-runner container syncs the updated config.json and credentials can be successfully resolved, so it's not a real issue, but there's no indication in the CLI that a restart is required or that credentials are not synced; I had to dig around to figure this out.

Reproducing

# Stop runner and logout
docker model stop-runner
docker logout

# Start runner and login
docker model start-runner
docker login -u [username]

# Attempt to push a model
docker model push ... # fails, even though you just logged in

# Check config.json inside model runner
docker exec docker-model-runner cat /home/modelrunner/.docker/config.json  # does not contain new entry

# Restart model-runner and retry
docker model restart runner
docker model push ... # succeeds
docker exec docker-model-runner cat /home/modelrunner/.docker/config.json  # contains new entry

Version

• docker model version:

  Client:
  Version:    v1.2.1
  OS/Arch:    linux/amd64
  
  Server:
  Version:    v1.2.1
  Engine:     Docker Engine
  

• docker version:

  Client: Docker Engine - Community
  Version:           29.5.2
  API version:       1.54
  Go version:        go1.26.3
  Git commit:        79eb04c
  Built:             Wed May 20 14:42:04 2026
  OS/Arch:           linux/amd64
  Context:           default
  
  Server: Docker Engine - Community
  Engine:
    Version:          29.5.2
    API version:      1.54 (minimum version 1.40)
    Go version:       go1.26.3
    Git commit:       568f755
    Built:            Wed May 20 14:38:16 2026
    OS/Arch:          linux/amd64
    Experimental:     false
  containerd:
    Version:          v2.2.4
    GitCommit:        193637f7ee8ae5f5aa5248f49e7baa3e6164966e
  runc:
    Version:          1.3.5
    GitCommit:        v1.3.5-0-g488fc13e
  docker-init:
    Version:          0.19.0
    GitCommit:        de40ad0