27.1 Typical Cluster Management Tasks

There are quite a few tasks we might want to perform when managing a cluster. Consequently, any form of "cookbook" is going to be based not around a single specific task but looking at how we can minimize downtime when managing the cluster. Here we summarize which cluster- and package- related tasks can and cannot be performed without interrupting service.

Cluster Modifications

Change to Cluster Configuration	Required Cluster State
Add a new node.	All cluster nodes must be running.
Delete an existing node.	A node can be deleted even if it is down or unreachable.
Change maximum configure packages.	Cluster must not be running.
Change timing parameters.	Cluster must not be running.
Change cluster lock configuration.	Cluster must not be running.
Change serial heartbeat configuration.	Cluster must not be running.
Change IP address for heartbeats.	Cluster must not be running.
Change addresses of monitored subnets.	Cluster must not be running.

Package Modifications

Change to Package Configuration	Required Package State
Add a new package.	Other packages can be running.
Remove a package.	Package must be halted. Cluster can be running.
Add a new node.	Package(s) may be running.
Remove a node.	Package(s) may be running on different nodes.
Add/remove a new service process.	Package must be halted.
Add/remove a new subnet.	Package must be halted. Cluster may need halting if subnet is new to the cluster.
Add/remove a new EMS resource.	Package must be halted. Cluster may need halting if EMS resource is new to the cluster.
Changes to the run/halt script contents	Recommended that package be halted to avoid any timing problems while running the script.
Script timeouts	Package may be running.
Service timeouts	Package must be halted.
Failfast parameters	Package must be halted.
Auto_Run	Package may be running.
Local LAN failover	Package may be running.
Change node adoption order.	Package may be running.

There are quite a lot of permutations to go though. I am not going to go through every one here. I will perform some of the more common tasks:

Adding a node to a cluster.
Adding a new node to a package.
Adding a new package to the cluster utilizing a Serviceguard Toolkit.
Modifying an existing package to use EMS resources.
Deleting a package from the cluster.
Deleting a node from the cluster.

- Including deleting a node from a package.
Discussing the process of rolling upgrades within a cluster.
Installing and using the Serviceguard Manager GUI.

These individual tasks give you a template of the steps to perform in order to effect changes within your cluster. Let's start by adding a node to the cluster.