[Linux-cluster] 2 node cluster w/o shared storage and custom script

[brem belguebli]

Hi Rafael,


2009/10/19 Rafael Micó Miranda <rmicmirregs at gmail.com>:
> Hi all,
>
> I've been requested to design a solution for a 2 node, active-passive,
> cluster of Maven (http://maven.apache.org/)
>
> The cluster will be formed by:
>
> - 2 front-end nodes in which the Maven service will be run, in an
> active-passive configuration (active-backup)
> - I will use HP-ilo fencing devices as the nodes are HP servers
> - a NFS mountpoint in which Maven can storage its files, served by a NAS
> cluster
> - a SQL database
>
> The need of an active-passive configuration is because, as I've been
> told, the front-end nodes cannot run Maven at the same time because it
> will cause database corruption.
>
> I'm accustomed to clusters in which nodes share a shared storage node,
> so i could use a Qdisk daemon in a 2 node cluster in addition to fencing
> to keep cluster quorate. This is not the situation as i will not have
> available a shared storage device, and this will be the first cluster
> using CMAN to be used in the company (i built the older ones with
> Linux-HA).
>
> I have some doubts about the better way to achieve this configuration,
> and I will like to share it with you and get your recommendations:
>
> 1.- "Scrip resource": as official RHEL 5.4 documentation says: "The
> script resource allows a standard LSB-compliant init script to be used
> to start a clustered service."
>
> I'm used to LSB scripts as part of the Linux-HA project:
> http://www.linux-ha.org/LSBResourceAgent
>
> Is there any further information of the LSB compliance for resource
> scripts in RHEL ?
>
Try this link (that you may already know !)
http://sources.redhat.com/cluster/wiki/RGManager
>
> 2.- Service operational status: does rgmanager implement any way to
> check the status of the "script" resources? If so, will the "script"
> resource need an "status|monitor" method? How often will rgmanager check
> the status of the resource?
>
This is in the your script resource metadata,  under the <action/>
section, you can define the interval at which rgmanager will launch
the "status|monitor" action.

It will have to return 0 if everythng is fine. (this is the LSB
compliance thing)
>
> 3.- NFS resource operational status: same as above: does rgmanager
> implement any way to check the status of the "nfs mountpoint" resources?
> How often will rgmanager check the status of the resource?
>
same as above, check the interval metadata settings
>
> 4.- Qdisk: As far as i know, i will not be able to use Qdisk here. I
> plan to use the 2 node cluster configuration:
>
> <cman expected_votes="1" two_node="1"/>
>
> Is there any other consideration to take into account to keep the
> cluster quorate?
>
http://sources.redhat.com/cluster/wiki/FAQ/CMAN#two_node_dual may give
you additionnal information
>
>
> Any help/recommendations will be appreciated.
>
> Cheers,
>
> Rafael
>
> --
> Rafael Micó Miranda
>
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