Docker / Volumes, Filesystems & Recovery
Find why a Docker application cannot write to its mounted data
The mount can be declared read-only or the underlying filesystem can reject writes for another reason. Inspect declared mount access first.
Environment and inputs: Docker Engine · Compose v2 and Buildx where specified; Linux containers unless noted. Verify daemon context, installed feature support and authorized host or Swarm manager access first.
Start with this check
Confirm the environment and replace sample objects, namespaces, images, paths and hosts with approved targets. Share only relevant, sanitized output. Follow the workload owner’s process for changes.
docker container inspect --format '{{json .Mounts}} {{.HostConfig.ReadonlyRootfs}}' appRead the result
Mount RW metadata and the root-filesystem setting describe configured intent. Backend permissions, export policy and storage health still apply.
Resolve and verify
Locate the failing path, compare the application's required writes with the approved design and repair the demonstrated layer. Validate a safe intended operation.
Before changing production
Do not make every mount writable or override a storage-protection state without investigating its cause.