[Pacemaker] Seeking advice on debian 2 node active/passive webserver

[Raoul Bhatia [IPAX]]

On 12/30/2009 10:04 AM, fred at fredleroy.com wrote:
> Hi all,
> 
> I'm a real newbie to pacemaker and after quite a few reading, I believe my
> setup would be the following :
> - 2 node cluster active/passive
> - using debian lenny, 1 nic per node, hard raid1 on each node
> - plan to use the corosync/pacemaker package
> - each node will host drdb (protocol c), ip, apache and mysql services
> - drdb will be used for apache and mysql conf and data files
> - will group ip, apache and mysql
> - will use ms for drdb
> - drdb will be using internal meta data
> - group of services will be collocated on drdb master
> - order group after drdb master.
> 
> Is this a workable setup ?

we're basically doing the same for a couple of customers.
with either 1 or more different drbd devices (for each service).
e.g.

example crm status output:
> Master/Slave Set: ms_drbd_data
>         Masters: [ node1 ]
>         Slaves: [ node2 ]
> Resource Group: group_data
>     fs_data     (ocf::heartbeat:Filesystem):    Started node1
> Resource Group: group_webservice
>     wwwip       (ocf::heartbeat:IPaddr2):       Started node1
>     apache2     (ocf::heartbeat:apache):        Started node1
> Resource Group: group_mysql
>     intip_sql   (ocf::heartbeat:IPaddr2):       Started node1
>     mysql-server        (ocf::heartbeat:mysql): Started node1
> stonith_rackpdu_node1  (stonith:external/rackpdu):     Started node2
> stonith_rackpdu_node2  (stonith:external/rackpdu):     Started node1

however, i'm still on some old, testing debian packages:
* pacmemaker 1.0.4-2ec1d189f9c23093bf9239a980534b661baf782d with
* openais-legacy 0.80.5+svn20090606-1~bpo50+1

thus i cannot directly comment on corosync/pacemaker.

> I'm a bit worried about performance issues regarding disk latency,
> especially with one nic (lan is gigabit).

we have 2 nics per server. 1 for external services and 1 with a cross
over cable for fast drbd replication. drbd tuning might be an important
issue for you.

> Also I would like to monitor operations of all services in the group (ip,
> apache and mysql) and drdb so if one fails a switch of node is performed.
> I did not understand if this was feasible with lsb (mysqld, for all the
> other services i'll try to use the ofc) ?

afairc the lsb complient scripts use the "/etc/init.d/lsb-script
status" command to monitor the resource.

but for each service you mentioned (mysql, apache, ip, drbd) there is a
corresponding ocf compliant resource agent.


cheers,
raoul
-- 
____________________________________________________________________
DI (FH) Raoul Bhatia M.Sc.          email.          r.bhatia at ipax.at
Technischer Leiter

IPAX - Aloy Bhatia Hava OEG         web.          http://www.ipax.at
Barawitzkagasse 10/2/2/11           email.            office at ipax.at
1190 Wien                           tel.               +43 1 3670030
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