RHEL6 clustering OS Setup and storage

[rhel6_cluster]

Hi,

I am setting up RHEL Clustering for the first time therefore please help me to contiue.

1. I have 2 BL460 G7 blades, storage HP P6000 for quorum and shared disks and planning to use iLO for fencing.

Now i am preparing for OS installation. Therefore can anyone help me ?

To share application i am thinking of installing software in /opt, in SAN storage so that both the node can share the location.

 therefore during RHEL installation do i need to map the vDisks from SAN to /opt  or after OS installation i later mount new vDisk from SAN to /opt?

Also how can i add quorum disks? Also help me to setup iLO?

If anything needs to be done please guide me!

I will be very much greatful to receive response on it.

Thanks! much appriciated..

[Matti_Kurkela]

> To share application i am thinking of installing software in /opt, in SAN storage so that both the node can share the location.

Remember that if you want both nodes to access the shared disk simultaneously, you must use GFS2 or a similar cluster filesystem. For regular non-cluster filesystems, the shared disk can be mounted on only one node at a time. In a failover situation, the cluster infrastructure will make sure that the disk is unmounted from the failing node (or that the failing node is successfully fenced) before mounting it on the other node and restarting the clustered service(s) there.

> during RHEL installation do i need to map the vDisks from SAN to /opt  or after OS installation i later mount new vDisk from SAN to /opt?

Both ways are certainly possible, but I think mounting a new vDisk after the installation might be easier, as you can have a full set of tools available for identifying and configuring the vDisks instead of just the installation UI.

However, I would suggest mounting the vDisk as e.g. /opt/application_name, not as /opt.

Making the shared disk be /opt would make the installation and use of hp-health, hp-snmp-agents and other HP hardware monitoring utilities difficult, as these install to /opt/hp and would be available on the active cluster node(s) only if /opt is a shared disk. And if you install the System Management Homepage, I'm not sure if it can run on a shared GFS filesystem: it might have a built-in assumption that its working directory is on a local filesystem.

> how can i add quorum disks?

Once you've installed the RHEL6 clustering software, see "man 5 qdisk" and "man 8 mkqdisk".

 
Chapter 3.5.4 in the RHEL 6 Cluster Administration document might be useful too:

https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Cluster_Administration/index.html

I would highly recommend the RedHat Clustering and Storage Management course:

http://www.redhat.com/training/courses/rh436/

The quorum disk should ideally be on its own LUN/vDisk, which is not included in any cluster volume group. It does not need to be big: 10 megabytes or so is enough. If you use multipathing, you might want to give the quorum disk a custom multipath name to make it easily distinguishable.

> Also help me to setup iLO?

What's your problem with it?

To set up initial iLO users and network parameters, press F8 when prompted when the system boots. (The F8 key is used for configuring the SmartArray controller too, so you must look for the iLO prompt and press the key while the prompt is visible.)

Alternatively, plug the iLO into a network segment that has a DHCP server, then use the iLO MAC address, username and password in the server's toe-tag to make an initial connection over the network with a web browser. (Look up the iLO IP using the information stored by the DHCP server, depending on your DHCP server implementation. Or if the network segment has dynamic DNS configured too, the iLO will attempt to register its name to the domain automatically, so you may be able to just use the default name listed in the toe-tag.)

For iLO fencing, you will need to configure a iLO user account that is allowed to control the server's power switch (Virtual Power Button).

I think the BL460 G7 probably has iLO 3, so you'll need to know that the required fencing agent for iLO 3 is fence_ipmilan, not fence_ilo as with older iLO versions.

See this RHKB article for more details: (valid RedHat subscription required)

https://access.redhat.com/knowledge/solutions/54843

[rhel6_cluster]

Thanks a lot! I will try to setup accordingly!