README.md

rbd-lock

A convenience container to acquire a lock on an RBD image (or fail) and (optionally) set an etcd key with that lockid.

Make sure to pass your /etc/ceph path as a volume/bind-mount.

It uses the following environment variables, if present:

IMAGENAME: this should be of the form poolName/imageName, and you may override this by passing the image name as the first argument
LOCKNAME: this is an arbitrary text name for the lock, and you may override this by passing the lock name as the second argument. The LOCKNAME will default to the HOSTNAME of the machine.
ETCD_LOCKID_KEY: this is the key name which will be set with the lock id acquired from Ceph after a successful lock.
ETCDCTL_PEERS is a comma seperated list of etcd peers (e.g. http://192.168.2.4:4001)
etcdctl is used to set the key, so any environment variable which acts upon etdctl will be honored within the execution.

Note: A lock is acquired if and only if the return value is 0. If the lock id was obtained, it will be returned as the output.

Example:

docker run --rm -v /etc/ceph:/etc/ceph ceph/rbd-lock myPool/myImage myLockName