Feb 252014

Hi all,

This is more a note to myself on how to configure stgt to talk to a Ceph rbd. Everyone seems to recommend patching tgt-admin: this is simply not necessary. The challenge is the lax way that tgt-admin parses the configuration file.

My scenario: VMWare ESXi virtual machine host, needing to use storage on Ceph.
I have 3 storage nodes running ceph-mon and ceph-osd daemons. They also have a version of tgtd that supports Ceph. (See the ceph-extras repository.)

The /etc/tgt/conf.d/${CLIENT}.conf configuration file. (I’m putting all the targets for ${CLIENT} here.)

# Target naming: iqn.yyyy-mm.backwards.domain.your:client.target
# where yyyy-mm: year and month of target creation
# backwards.domain.your: Your domain name; written backwards.
# client.target: A name for the target, since it's for one client here I name it
# as the client's host name then give the rest some descriptive title.
<target iqn.2014-02.domain.my:my-client.my-target-name>
    driver iscsi
    bs-type rbd
    backing-store pool-name/rbd-name
    initiator-address ip.of.my.client

For better or worse, I run the tgt daemon on the Ceph nodes themselves. Multipath I’m not sure about at this point, I’ve set up the targets on all of my Ceph nodes so I can connect to any, but I have not tested this yet.

To enable that target:

# tgt-admin -v -e

Then to verify:

# tgt-admin -s

You should see your LUNs listed.