Docker Engine managed plugin to manage RBD volumes.
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Joan Vega
Joan Vega new: mkfs now with options: mkfsOptions with default "-O mmp"
new: mount now with options: default mountOptions "-o noatime"
mod: rbd watchers do not stop the image mount.

With the introduction of ext4 "Multiple Mount Protection" we can deal with the multi mounts in a more rational way (https://ext4.wiki.kernel.org/index.php/Ext4_Disk_Layout#Multiple_Mount_Protection).
The usage of Watchers carries complex corner cases i.e. when after a crash ceph takes too much time blacklist osd nodes.

bump to version v2.0.0
Latest commit cac382d Oct 20, 2018

README.md

Docker volume plugin for RBD

Docker Engine managed plugin to for RBD volumes.

This plugins is managed using Docker Engine plugin system. https://docs.docker.com/engine/extend/

Requirements

  1. Docker >=1.13.1 (recommended)
  2. Ceph cluster

Why another docker rbd plugin?

  1. Docker v2 plugin
  2. No external service dependencies other than Ceph.

Using this volume driver

1 - Driver config options

LOG_LEVEL=[0:ErrorLevel; 1:WarnLevel; 2:InfoLevel; 3:DebugLevel] defaults to 0

RBD_CONF_DEVICE_MAP_ROOT="/dev/rbd"
RBD_CONF_POOL="ssd"
RBD_CONF_CLUSTER=ceph
RBD_CONF_KEYRING_USER=client.admin

Mount options defaults to "--options=noatime" (extended syntax with no spaces)
MOUNT_OPTIONS="--options=noatime"

2 - Install the plugin

docker plugin install wetopi/rbd \
  --alias=wetopi/rbd \
  LOG_LEVEL=1 \
  RBD_CONF_POOL="ssd" \
  RBD_CONF_CLUSTER=ceph \
  RBD_CONF_KEYRING_USER=client.admin

3 - Create and use a volume

Available volume driver options:

fstype: optional, defauls to ext4
mkfsOptions: optional, defaults to '-O mmp' (Multiple Mount Protection)
mountOptions: optional, defaults to '-o noatime'
size: optional, defaults to 512 (512MB)
order: optional, defaults to 22 (4KB Objects)

3.A - Create a volume:

https://docs.docker.com/engine/reference/commandline/volume_create/

docker volume create -d wetopi/rbd -o size=206 my_rbd_volume

docker volume ls
DRIVER              VOLUME NAME
local               069d59c79366294d07b9102dde97807aeaae49dc26bb9b79dd5b983f7041d069
local               11db1fa5ba70752101be90a80ee48f0282a22a3c8020c1042219ed1ed5cb0557
local               2d1f2a8fac147b7e7a6b95ca227eba2ff859325210c7280ccb73fd5beda6e67a
wetopi/rbd          my_rbd_volume

3.B - Run a container with a previously created volume:

docker run -it -v my_rbd_volume:/data --volume-driver=wetopi/rbd busybox sh

3.C - Run a container with an anonymous volume:

docker run -it -v $(docker volume create -d wetopi/rbd -o size=206):/data --volume-driver=wetopi/rbd -o size=206 busybox sh

NOTE: Docker 1.13.1 does not support volume opts on docker run or docker create

3.D - Create a service with a previously created volume:

 docker service create --replicas=1 \
   --mount type=volume,source=my_rbd_volume,destination=/var/lib/mysql,volume-driver=wetopi/rbd \
   mariadb:latest

3.E - Create a service with an anonymous volume:

 docker service create --replicas=1 \
   -e MYSQL_ROOT_PASSWORD=my-secret-pw \
   --mount type=volume,destination=/var/lib/mysql,volume-driver=wetopi/rbd,volume-opt=size=512 \
   mariadb:latest

4 - Upgrading the plugin

4.1 Upgrade without tag versioning:

docker plugin disable -f wetopi/rbd
docker plugin upgrade wetopi/rbd

Update setting [Optional]:

docker plugin set wetopi/rbd \
  LOG_LEVEL=2 \
  RBD_CONF_POOL="ssd" \
  RBD_CONF_KEYRING_USER=client.admin

Enable the plugin:

docker plugin enable wetopi/rbd

Known problems:

  1. WHEN docker plugin remove + install THEN containers running in plugins node lost their volumes SOLUTION restart node (swarm moves containers to another node + restart free up the Rbd mapped + mounted images)

Troubleshooting

Check your plugin is enabled:

docker plugin ls

ID                  NAME                DESCRIPTION               ENABLED
fff19fa9a622        wetopi/rbd:latest   RBD plugin for Docker     true

Exec an interactive bash in plugins container:

Find the full id:

docker-runc list | grep fff19fa9a622

Exec an interactive shell:

docker-runc exec -t fff19fa9a622885f5bcc30c0199046761825b037b25523540647b12ccf84403be bash

Log your driver:

If this container is not running or restarting, then check your docker engine log i.e.

tail -f /var/log/upstart/docker

or its equivalent

journalctl -f -u docker.service

Use curl to debug plugin socket issues.

To verify if the plugin API socket that the docker daemon communicates with is responsive, use curl. In this example, we will make API calls from the docker host to volume and network plugins using curl to ensure that the plugin is listening on the said socket. For a well functioning plugin, these basic requests should work. Note that plugin sockets are available on the host under /var/run/docker/plugins/

curl -H "Content-Type: application/json" -XPOST -d '{}' --unix-socket /var/run/docker/plugins/546ac5b9043ce0f49552b14e9fb73dc78f1028d2da7e894ab599e6546566c0df/rbd.sock http:/VolumeDriver.List

{"Mountpoint":"","Err":"","Volumes":[{"Name":"rbd_test","Mountpoint":"","Status":null},{"Name":"demo_test","Mountpoint":"/mnt/volumes/demo_test","Status":null}],"Volume":null,"Capabilities":{"Scope":""}}

Changelog

v2.0.0

new: mkfs now with options: mkfsOptions with default "-O mmp" new: mount now with options: default mountOptions "-o noatime" mod: rbd watchers do not stop the image mount.

No more volume lock control neded: With the introduction of ext4 "Multiple Mount Protection" we can deal with the multi mounts in a more rational way (https://ext4.wiki.kernel.org/index.php/Ext4_Disk_Layout#Multiple_Mount_Protection). The usage of Watchers carries complex corner cases i.e. when after a crash ceph takes too much time blacklist osd nodes.

v1.0.1

v1.0.0

New:

  • Removed Consul dependency: consul is no more needed. This new release gathers state asking rbd.
  • RBD advisory locks thanks to rbd state watchers. A volume mount returns error if it has a watcher. Now it is not possible for a client to attach a volume that is already attached to another node.

Incompatible backwards changes:

  • Rbd pool: is a plugin config param. (changed in order to avoid the need to persist state of volumes).
  • Rbd pool: is no more an option during volume create.
  • POST /VolumeDriver.Create gives err if volume exists.
  • POST /VolumeDriver.Mount gives err if volume has watchers.

Developing

You can build and publish the plugin with:

make all

Vendor dependencies

vendor dir is maintained using dep dependency tool: https://github.com/golang/dep

More info: https://github.com/golang/dep/blob/master/FAQ.md

Update dependencies

More info: https://golang.github.io/dep/docs/daily-dep.html

THANKS

https://github.com/docker/go-plugins-helpers

https://github.com/yp-engineering/rbd-docker-plugin

LICENSE

MIT