FAQ

Contents

• 1   Docker gives the error "[graphdriver] prior storage driver \"aufs\" failed: driver not supported"
  • 1.1   If you care about your containers
  • 1.2   If you do not need to retain your containers
• 2   docker run gives the error "invalid character '/' after object key:value pair"

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This page provides answers to Frequently Asked Questions (and that's a FAQ! :-)

1   Docker gives the error "[graphdriver] prior storage driver \"aufs\" failed: driver not supported"

Docker will give this error if you try to start a container but:

• you modified the docker configuration manually from aufs to another storage driver (say, overlayfs using the dockerd option --storage-driver=overlay).
• your host kernel no longer supports the storage driver specified (aufs).

For the latter scenario...

1.1   If you care about your containers

• reboot using a kernel that does still support aufs (but take care if the kernel was updated due to security issues!)
• export the docker images/containers.
• reboot into the latest kernel (where dockerd will be using the modified storage driver).
• import the docker images/containers.
• restart the containers.

1.2   If you do not need to retain your containers

If you don't care about the containers you previously created using the aufs driver, you could consider deleting /var/lib/docker/ and restarting the docker service.

2   docker run gives the error "invalid character '/' after object key:value pair"

If you see this error:

$ docker run -ti --runtime cor busybox sh
docker: Error response from daemon: invalid character '/' after object key:value pair.

... you have probably configured docker to use the helper script "cc-oci-runtime.sh" as documented on the Debugging page. The issue is that Docker will refuse to use the runtime if you quote the path to the runtime:

• BAD (runtime contains quote marks):

  ExecStart=/usr/bin/dockerd -D --add-runtime cor="/usr/bin/cc-oci-runtime.sh" --default-runtime=cor
  

• BAD (runtime contains quote marks):

  ExecStart=/usr/bin/dockerd -D --add-runtime cor="cc-oci-runtime.sh" --default-runtime=cor
  

• Good (no quotes):

  ExecStart=/usr/bin/dockerd -D --add-runtime cor=/usr/bin/cc-oci-runtime.sh --default-runtime=cor
  

• Good (no quotes):

  ExecStart=/usr/bin/dockerd -D --add-runtime cor=cc-oci-runtime.sh --default-runtime=cor
  

This seems to be a bug with the way docker parses option arguments.

To resolve the issue:

• Edit the file and remove the quotes

• Force systemd to reload the config file:

  sudo systemctl daemon-reload
  

• Restart the docker daemon:

  sudo systemctl restart docker