Volumes

With sdc-docker, there are some limitations on volumes that are slightly different from Docker Inc's docker:

• there is a limit of 8 'data' volumes per container
• 'host' volumes (/hostpath:/containerpath) are not supported
• you cannot delete a container which has a volume that another container is sharing (via --volumes-from), you must first delete all containers using that volume.
• there is a limit of 1 --volumes-from argument per container
• When you use --volumes-from you are necessarily coprovisioned with the container you are sharing the volumes from. If the physical host on which the source container exists does not have capacity for the new container, provisioning a new container using --volumes-from will fail.
• When you use --volumes-from, volumes that don't belong to the container specified (including those that this container is sharing from others) are ignored. Only volumes belonging to the specified container will be considered.

Experimental support for NFS shared volumes

The NFS shared volumes feature is described in detail by its corresponding RFD document.

To enable support for NFS shared volumes in Triton, run the following command line from the head node:

sdcadm post-setup volapi
sdcadm experimental nfs-volumes docker
sdcadm experimental nfs-volumes docker-automount

This command will create a new core zone that runs the VOLAPI service, which implements the Volumes API. It will also enable the experimental_docker_nfs_shared_volumes and experimental_docker_automount_nfs_shared_volumes metadata properties in SAPI.

At this point, all docker volume commands are supported but only for the 'tritonnfs' volume driver, which provides support for NFS shared volumes. Note that the 'tritonnfs' volume driver is considered to be the default and thus does not need to be specified in the docker volume create command for it to work.

The experimental_docker_nfs_shared_volumes SAPI flag can be set to false in SAPI to disable support for NFS shared volumes by running the following command line:

sdcadm experimental nfs-volumes docker -d

After disabling this setting, running docker volume commands will result in an error message.