[Samba] CTDB and LVS

[Martin Schwenke]

Hi Leszek,

On Thu, 15 Dec 2022 14:07:58 +0100, Leszek Szczepanowski via samba
<samba at lists.samba.org> wrote:

> I wanted to have LVS VIP additionally to the DNS round-robin load balancing.
> I have configured the following files on all my CTDB nodes:
> 
> /etc/ctdb/lvs_nodes:
> 
> [root at fs01 ctdb]# cat lvs_nodes
> 10.254.94.11
> 10.254.94.12
> 10.254.94.13
> 10.254.94.14
> 10.254.94.15
> 10.254.94.16
> 
> Those are internal IPs for the CTDB cluster (also used for GlusterFS
> internal traffic).
> 
> /etc/ctdb/script.options:
> 
> # 91.lvs
> CTDB_LVS_PUBLIC_IFACE=bridge0
> CTDB_LVS_PUBLIC_IP=10.46.68.30

> [...]

> But actually, nothing happens.
> 
> [root at fs01 ctdb]# ipvsadm
> IP Virtual Server version 1.2.1 (size=4096)
> Prot LocalAddress:Port Scheduler Flags
>   -> RemoteAddress:Port           Forward Weight ActiveConn InActConn  
> [root at fs01 ctdb]#
> 
> What I'm missing here?

I think you probably also need to set:

  CTDB_LVS_NODES=/etc/ctdb/lvs_nodes

If that doesn't work and if there is nothing in the logs, then...

Given that this is only handled by an event script, the best way to
debug might be to add "set -x" near the top of
/etc/ctdb/events/legacy/91.lvs.script and see what you find in the logs.

Note that, although CTDB's LVS support has some tests in the CTDB test
suite and I have hand-tested it in the past, I don't know of anyone
else who is using it.  You may find interesting things, including
bugs.  Please let us know if it works...

peace & happiness,
martin