manila/doc/source/devref/container_driver.rst

Container Driver

The Container driver provides a lightweight solution for share servers management. It allows to use Docker containers for hosting userspace shared file systems services.

Supported operations

• Create CIFS share;
• Delete CIFS share;
• Allow user access to CIFS share;
• Deny user access to CIFS share;
• Extend CIFS share.

Restrictions

• Current implementation has been tested only on Ubuntu. Devstack plugin won't work on other distributions however it should be possible to install prerequisits and set the driver up manually;
• The only supported protocol is CIFS;
• The following features are not implemented:
  • Manage/unmanage share;
  • Shrink share;
  • Create/delete snapshots;
  • Create a share fron a snapshot;
  • Manage/unmanage snapshots.

Known problems

• May demonstrate unstable behaviour when running concurrently. It is strongly suggested that the driver should be used with extreme care in cases other than building lightweight development and testing environments.

Setting up container driver with devstack

The driver could be set up via devstack. This requires the following update to local.conf:

enable_plugin manila https://git.openstack.org/openstack/manila <ref>
MANILA_BACKEND1_CONFIG_GROUP_NAME=london
MANILA_SHARE_BACKEND1_NAME=LONDON
MANILA_OPTGROUP_london_driver_handles_share_servers=True
MANILA_OPTGROUP_london_neutron_host_id=<hostname>
SHARE_DRIVER=manila.share.drivers.container.driver.ContainerShareDriver
SHARE_BACKING_FILE_SIZE=<backing file size>
MANILA_DEFAULT_SHARE_TYPE_EXTRA_SPECS='snapshot_support=false'

where <ref> is change reference, which could be copied from gerrit web-interface, <hostname> is the name of the host with running neutron

Setting Container Driver Up Manually

This section describes steps needed to be performed to set the driver up manually. The driver has been tested on Ubuntu 14.04, thus in case of any other distribution package names might differ. The following packages must be installed:

• docker.io

One can verify if the package is installed by issuing sudo docker info command. In case of normal operation it should return docker usage statistics. In case it fails complaining on inaccessible socket try installing apparmor. Please note that docker usage requires superuser privileges.

After docker is successfully installed a docker image containing necessary packages must be provided. Currently such image could be downloaded from https://github.com/a-ovchinnikov/manila-image-elements-lxd-images/releases/download/0.1.0/manila-docker-container.tar.gz. The image has to be unpacked but not untarred. This could be achieved by running 'gzip -d <imagename>' command. Resulting tar-archive of the image could be uploaded to docker via

sudo docker load --input <imagename.tar>

If the previous command finished successfully you will be able to see the image in the image list:

sudo docker images

The driver expects to find a folder /tmp/shares on the host where it is running as well as a logical volume group "manila_docker_volumes".

When installing the driver manually one must make sure that 'brctl' and 'docker' commands are present in the /etc/manila/rootwrap.d/share.filters and could be executed as root.

Finally to use the driver one must add a backend to the config file containing the following settings:

driver_handles_share_servers = True
share_driver = manila.share.drivers.container.driver.ContainerShareDriver
neutron_host_id = <hostname>

where <hostname> is the name of the host running neutron. (In case of single VM devstack it is VM's name).

After restarting manila services you should be able to use the driver.