Cloning a Ceph client auth key

 I don't recall any reason to do this other than using the same user and auth key to authenticate in different Ceph clusters, like in a multi-backend solution, or just because things get messy when you are not using a default configuration.

Sometimes, things get easy when we use the same user and auth key on both clusters for services to connect to, so let's see some background commands for managing users, keys, and permissions:

Create a new user and auth token (cinder client example):

root@ceph-admin:~# ceph auth get-or-create client.jerry
client.jerry
key: AQAZT05WoQuzJxAAX5BKxCbPf93CwihuHo27VQ==

So as you see the key is not a parameter, in a different server this will produce a completely different key.
Just to check, print the complete list of keys:

root@ceph-admin:~# ceph auth list
installed auth entries:

osd.0
key: AQCvCbtToC6MDhAATtuT70Sl+DymPCfDSsyV4w==
caps: [mon] allow profile osd
caps: [osd] allow *
osd.1
key: AQC4CbtTCFJBChAAVq5spj0ff4eHZICxIOVZeA==
caps: [mon] allow profile osd
caps: [osd] allow *
client.admin
key: AQBHCbtT6APDHhAA5W00cBchwkQjh3dkKsyPjw==
caps: [mds] allow
caps: [mon] allow *
caps: [osd] allow *
client.jerry
key: AQAZT05WoQuzJxAAX5BKxCbPf93CwihuHo27VQ==

Or print a user’s authentication key to standard output, execute the command in the following format

ceph auth print-key {TYPE}.{ID}

root@ceph-admin:~# ceph auth print-key client.jerry
AQAZT05WoQuzJxAAX5BKxCbPf93CwihuHo27VQ==

To change this in order to match with others, we need to update their keys and/or their capabilities, the import command is for this, remember their keys and their capabilities will update on existing users and create new ones, use the following format:

ceph auth import -i /path/to/keyring

The keyring file needs to be in this format, if not, the command will not work and the part of the work, it will just hang.

root@ceph-admin:~# cat jerry.key
[client.jerry]
key = AQAMP01WS8i8ERAAPspjwMzUm4SL00n+WppM6A==

Now we can update the auth key for the user jerry:

root@ceph-admin:~# auth import -i ./jerry.key
imported keyring

List again.

root@ceph-admin:~# ceph auth list
installed auth entries:

osd.0
key: AQCvCbtToC6MDhAATtuT70Sl+DymPCfDSsyV4w==
caps: [mon] allow profile osd
caps: [osd] allow *
osd.1
key: AQC4CbtTCFJBChAAVq5spj0ff4eHZICxIOVZeA==
caps: [mon] allow profile osd
caps: [osd] allow *
client.admin
key: AQBHCbtT6APDHhAA5W00cBchwkQjh3dkKsyPjw==
caps: [mds] allow
caps: [mon] allow *
caps: [osd] allow *
client.jerry
key: AQAMP01WS8i8ERAAPspjwMzUm4SL00n+WppM6A==

Done, I will continue posting these little helping tricks until the last post about multi-backend ceph is out.