Rootless Docker: Permission Error with NFS Drive

Rootless Docker and Permission Errors with NFS Home Directories

Docker is a popular containerization platform that allows developers to easily package and distribute their applications. Running Docker in a rootless mode can provide additional security benefits, but it can also introduce some challenges when it comes to managing volumes and permissions.

Mounting NFS Home Directories

One common use case is to mount a user's home directory as a Docker volume, so that they can access their files from within a container. This can be done using the fstab file, as shown in the following example:

This will mount the NFS share located at 192.168.2.102:/volume1/nuc_data/user1/docker_volumes/home/user1/docker_volumes to the host machine at /home/user1/docker_volumes.

Permission Errors

However, when running Docker in rootless mode, you may encounter permission errors when trying to access the NFS share. This is because the NFS client is trying to access the share as the root user, but the NFS server is configured to only allow access to specific users.

To resolve this issue, you can use the nfs4_setfacl command to set the appropriate permissions on the NFS share. For example:

This command will give the docker user read and execute permissions on the NFS share, as well as the current user. The -P option tells the command to apply the permissions recursively to all subdirectories and files.

Running Docker in rootless mode can provide additional security benefits, but it can also introduce some challenges when it comes to managing volumes and permissions. By using the nfs4_setfacl command, you can set the appropriate permissions on an NFS share to allow rootless Docker to access it.

References

• Docker Documentation: Rootless mode
• NFSv4 ACLs: NFSv4 ACLs

Note: The above references are provided for informational purposes only and should not be considered as an endorsement of any kind.