Docker-compose volume label test fails with plugin error

[rajanashok]

⇒ docker-compose -H 10.160.36.169:2375 up -d
Creating volume "vic_volume_with_label" with default driver
ERROR: error looking up volume plugin : plugin not found

YML file:

services:
  web:
    image: busybox
    command: top
    volumes:
      - volume_with_label:/data

volumes:
  volume_with_label:
    labels:
      - "label_key=label_val"

[chengwang86]

Apr  6 2017 17:04:10.931Z ERROR Handler for GET /v1.24/volumes/compose_volume_with_label returned error: No such volume: compose_volume_with_label
Apr  6 2017 17:04:10.984Z DEBUG [BEGIN] [github.com/vmware/vic/lib/apiservers/engine/backends.(*Volume).VolumeCreate:257] Volume.VolumeCreate
Apr  6 2017 17:04:10.984Z DEBUG [BEGIN] [github.com/vmware/vic/lib/apiservers/engine/backends.(*Volume).volumeCreate:227]
Apr  6 2017 17:04:10.984Z DEBUG [ END ] [github.com/vmware/vic/lib/apiservers/engine/backends.(*Volume).volumeCreate:227] [7.34µs] 
Apr  6 2017 17:04:10.984Z DEBUG [ END ] [github.com/vmware/vic/lib/apiservers/engine/backends.(*Volume).VolumeCreate:257] [40.526µs] Volume.VolumeCreate
Apr  6 2017 17:04:10.984Z ERROR Handler for POST /v1.24/volumes/create returned error: error looking up volume plugin : plugin not found

[stuclem]

Proposed release note:

---

• Using volume labels with docker-compose causes a plugin error. #4540
  Setting a label in a volume in the Docker compose YML file results in error looking up volume plugin : plugin not found.

---

@rajanashok and @chengwang86 please feel free to add more information in this issue.

[matthewavery]

@stuclem looks like that will be needed for now. Turns out that this will not be a super difficult issue to fix.(or should not be) but the soonest it can be pulled in is next sprint( sprint 9) and that is pending @mdubya66 and @mhagen-vmware 's approval.

[chengwang86]

@stuclem I discussed with @matthewavery about this. According to compose documentation here https://docs.docker.com/compose/compose-file/#volume-configuration-reference

An entry under the top-level volumes key can be empty, in which case it will use the default driver configured by the Engine (in most cases, this is the local driver). 

If the volume driver is empty, docker will use local as the default one. However, on vic
https://github.com/vmware/vic/blob/master/lib/apiservers/engine/backends/volume.go#L355
we will print the above error msg if the drivername is empty.

As a workaround, we can ask the customer to set the volume driver explicitly as local or vsphere in the compose file. E.g.,

volumes:
  volume_with_label:
    driver: local

[stuclem]

@chengwang86 done! Thanks

[corrieb]

Given that VIC only has one volume driver, we should default to using "vsphere" as the driver if none other is specified. This is a compatibility and UX issue. I've tripped over this as the error message isn't very informative.