tmpfs options are incompatible with type bind

Error message

tmpfs options are incompatible with type bind

What it means

Raised by handleBindToMount in docker/cli's compose converter (used by `docker stack deploy`) when a service volume declared as `type: bind` also carries a `tmpfs:` options block. Each mount type in the long volume syntax accepts only its own options struct, and the converter rejects any foreign options block outright rather than silently ignoring it.

Source

Thrown at cli/compose/convert/volume.go:133

		}
	}
	return result, nil
}

func handleBindToMount(volume composetypes.ServiceVolumeConfig) (mount.Mount, error) {
	result := createMountFromVolume(volume)

	if volume.Source == "" {
		return mount.Mount{}, errors.New("invalid bind source, source cannot be empty")
	}
	if volume.Volume != nil {
		return mount.Mount{}, errors.New("volume options are incompatible with type bind")
	}
	if volume.Image != nil {
		return mount.Mount{}, errors.New("image options are incompatible with type bind")
	}
	if volume.Tmpfs != nil {
		return mount.Mount{}, errors.New("tmpfs options are incompatible with type bind")
	}
	if volume.Cluster != nil {
		return mount.Mount{}, errors.New("cluster options are incompatible with type bind")
	}
	if volume.Bind != nil {
		result.BindOptions = &mount.BindOptions{
			Propagation: mount.Propagation(volume.Bind.Propagation),
		}
	}
	return result, nil
}

func handleTmpfsToMount(volume composetypes.ServiceVolumeConfig) (mount.Mount, error) {
	result := createMountFromVolume(volume)

	if volume.Source != "" {
		return mount.Mount{}, errors.New("invalid tmpfs source, source must be empty")
	}

View on GitHub (pinned to e9452d6e78)

Solutions

Remove the `tmpfs:` block from the bind-mount volume entry in the compose file
If tmpfs behavior was intended, change `type: bind` to `type: tmpfs` and drop the `source:` field
If both are needed, split into two separate volume entries, one bind and one tmpfs

Example fix

# before
volumes:
  - type: bind
    source: /host/data
    target: /data
    tmpfs:
      size: 10000000
# after
volumes:
  - type: bind
    source: /host/data
    target: /data

When it happens

Trigger: A compose file service volume with `type: bind` that also sets `tmpfs.size` (volume.Tmpfs != nil after parsing), passed through convert.Service/convertServiceVolumes during `docker stack deploy` or any code calling handleBindToMount.

Common situations: Copy-pasting a tmpfs volume entry and changing only `type` to bind; YAML indentation placing a tmpfs block under the wrong volume entry; templating/anchors merging option blocks from another mount definition.

Related errors

AI-assisted analysis of docker/cli@e9452d6e78 (2026-08-01). Data as JSON: /data/errors/b5e142a5617d5124.json. Report an issue: GitHub.