MCSG: Creating clustersΒΆ

Title:MCSG: Creating clusters
Author:Douglas O’Leary <dkoleary@olearycomputers.com>
Description:MCSG: Creating clusters
Date created:06/2007
Date updated:03/11/11
Disclaimer:Standard: Use the information that follows at your own risk. If you screw up a system, don’t blame it on me...

This section only details the commands needed to establish a cluster. Please ensure appropriate hardware and environmental setup has already been completed as documented in Managing MC/ServiceGuard Chapter 4.

NOTE (03/11/11): One of the more entertaining aspects of creating clusters is getting the networking set up correctly. As of MCSG 11.17, there’s a command called cmpreparecl which will automatically configure inetd, hosts, and nsswitch.conf for you. It makes the initial cluster conifugration significantly easier.

It does require direct root ssh access. If you don’t already have it set up, you can run csshsetup. Check Sudo vs ssh/pka to access root and ssh users’ guide for details on why you want to configure direct ssh/pka access to root and how to go about doing it.

To create a cluster, follow these steps:

  1. Install the MCSG software.

  2. Update /etc/lvmrc

    1. Set the AUTO_VG_ACTIVATE variable to 0
    2. Ensure any strictly local volume groups are activated via the custom_vg_activation() function call.
  3. Decide on an authentication scheme. Please see MCSG authentication issues for details.

    1. Root level trust relationship
    2. /etc/cmcluster/cmclnodelist
  4. Appropriately configure applications with LVM.

    1. All data and binaries needed to run an application should be within the same volume group or sets of volume groups.
    2. All data not associated with an application should be loated in volume groups separate from the application.
  5. Generate a cluster configuration file

    cmquerycl -C ${config} -v -n ${node1} -n ${node2} -n ${node3}

  6. Edit the cluster configuration.

    1. Supply a name for the cluster
    2. Update the MAX_CONFIGURED_PACKAGES variable to an appropriate number.
    3. Modify any other parameters as needed.
  7. Check the configuration file

    cmcheckconf -C ${config}

  8. Apply the configuration

    cmapplyconf -C ${config}

  9. Copy the configuration file to the other nodes.