Ceph: snapshot a RBD instance with QEMU-UTILS

Jan 20, 2014 shan

Quick tip to perform a full snapshot of an RBD image. (only MtG players can recognize this picture!)

bash $ qemu-img convert -O raw rbd:<pool>/<rbd-images> <destination-snapshot-file>

The qemu-img tool supports several parameters:

if you want to authenticate with a specific user you can use: id=<username>
if you want to point to a specific Ceph config file you can use: conf=/etc/ceph/ceph.conf

Obviously your ceph.conf has a dedicated section that points to the user key file (where the file contains the key):

[client.leseb]
    keyring = /etc/ceph/ceph.client.leseb.keyring

Final note, every option are separated by a :, so this will give you for example:

bash $ qemu-img convert -O raw rbd:instances/vmdisk01:id=leseb:conf=/etc/ceph/ceph-leseb.conf /tmp/snap