volplugin

README

volplugin: cluster-wide volume management for container ecosystems

Note: Most of this documentation is about the open source project. If you came to try Contiv Storage, read our documentation.

volplugin controls Ceph RBD or NFS devices, in a way that makes them easy to use for devs with docker, and flexible to configure for ops. Reference your volumes with docker from anywhere your storage is available, and they are located and mounted. Works great with Compose and Swarm, now Mesos too!

Our profiles system makes instantiating lots of similar class volumes a snap, allowing for a variety of use cases:

• Give your dev teams full-stack dev environments (complete with state) that arrive on demand. They can configure them.
• Scale your stateful containers in a snap with our snapshot facilities, just volcli volume snapshot copy and refer to the volume immediately. Anywhere. (Ceph only)
• Container crashed? Host died? volplugin's got you. Just re-init your container on another host with the same volume name.

volplugin currently only supports Docker volume plugins. First class scheduler support for: Kubernetes and Mesos will be available before the first stable release.

• On-the-fly image creation and (re)mount from any Ceph source, by referencing a policy and volume name.
• Manage many kinds of filesystems, including providing mkfs commands.
• Snapshot frequency and pruning. Also copy snapshots to new volumes!
• Ephemeral (removed on container teardown) volumes
• IOPS limiting (via blkio cgroup)

volplugin is still alpha at the time of this writing; features and the API may be extremely volatile and it is not suggested that you use this in production.

Try it out

volplugin currently does not run in a container. The other volplugin-related components do, but volplugin does not. volplugin must be run on the host where the volumes are to be mounted.

Prerequisites:

Note: this takes a little more dedication than we'd like. We're working on it!

For a small VM (1 VM, 4096MB ram) for running just the tools and trying it out, you can run:

$ make demo

Note that you will still need ansible, virtualbox, and vagrant.

Development/Mock Production env

For a more comprehensive version of the system including swarm support across several hosts, see below:

On the host, equivalent or greater:

• 12GB of free RAM. Ceph likes RAM.
• VirtualBox 5.0.2 or greater
• Vagrant 1.8.x
• Ansible 2.0+
  • On OS X: brew install ansible: you can will need Homebrew
  • Ubuntu/Debian: apt-get install ansible -y
  • CentOS/RHEL: yum install ansible -y
• Go 1.6 to run the system tests.

Your guests will configure themselves.

Running the processes

Be sure to start and run the environment with make start before you continue with these steps. You must have working vagrant, virtualbox, and ansible. If you are behind a proxy server, set the https_proxy same as the http_proxy. Ansible has a current limitation (https://github.com/ansible/ansible/issues/10941), that it only supports http:// proxy. So, https_proxy should be set to "http://<proxyserver>:<port>"

These instructions ssh you into the mon0 vm. If you wish to test the cross-host functionality, ssh into mon1 or mon2 with vagrant ssh.

1. Run the suite: make run.
2. SSH into the host: make ssh.
3. Upload policy information: volcli policy upload policy1 < /testdata/ceph/policy1.json
4. Add a docker volume with policy/name syntax:

• docker volume create -d volplugin --name policy1/foo

1. Run a container with the volume attached:

• docker run -it -v policy1/foo:/mnt ubuntu bash

1. You should have a volume mounted at /mnt, pointing at a /dev/rbd# device. Exit the shell to unmount the device.

To use the volume again, either docker volume create it on another host and start a container, or just do it again with a different container on the same host. Your data will be there!

volcli has many applications including volume and mount management. Check it out!

Development Instructions

See our CONTRIBUTING document as well.

Please read the Makefile for most targets. If you make build you will get apiserver/volplugin/volcli installed on the guests, so make run-build if you want a go install'd version of these programs on your host. apiserver/volplugin do not run on anything but linux (you can use volcli, however, on other platforms).

If you wish to run the tests, make test. The unit tests (make unit-test) live throughout the codebase as *_test files. The system tests / integration tests (make system-test) live in the systemtests directory. Note that make system-test will not successfully run on OSX due to dependencies on unavailable libraries.