Managing Serviceguard Nineteenth Edition, Reprinted June 2011

Halting a Node or the Cluster while Keeping Packages Running
There may be circumstances in which you want to do maintenance that involves halting a node,
or the entire cluster, without halting or failing over the affected packages. Such maintenance might
consist of anything short of rebooting the node or nodes, but a likely case is networking changes
that will disrupt the heartbeat.
New command options in Serviceguard A.11.20 (collectively known as Live Application Detach
(LAD)) allow you to do this kind of maintenance while keeping the packages running. The packages
are no longer monitored by Serviceguard, but the applications continue to run. Packages in this
state are called detached packages.
When you have done the necessary maintenance, you can restart the node or cluster, and normal
monitoring will resume on the packages.
NOTE: Keep in mind that the purpose of the LAD capabilities is to allow you do maintenance
on one or more nodes, or the entire cluster. If you want to do maintenance on individual packages,
or on elements of the cluster configuration that affect only one package, or a few packages, you
should probably use package maintenance mode; see “Maintaining a Package: Maintenance
Mode” (page 273).
What You Can Do
You can do the following.
• Halt a node (cmhaltnode (1m) with the -d option) without causing its running packages
to halt or fail over.
Until you restart the node (cmrunnode (1m)) these packages are detached — not being
monitored by Serviceguard.
• Halt the cluster (cmhaltcl (1m) with the -d option) without causing its running packages
to halt.
Until you restart the cluster (cmruncl (1m)) these packages are detached — not being
monitored by Serviceguard.
• Halt a detached package, including instances of detached multi-node packages.
• Restart normal package monitoring by restarting the node (cmrunnode) or the cluster
(cmruncl).
Rules and Restrictions
The following rules and restrictions apply.
• All the nodes in the cluster must be running A.11.20.
• All the configured cluster nodes must be reachable by an available network (not necessarily
a network that is configured into the cluster).
• You must be root user (superuser) to halt or start a node or cluster with Live Application Detach,
and to halt a detached package.
• Live Application Detach is not supported for SGeRAC clusters configured with SLVM or ASM.
• Live Application Detach is not supported for clusters using the Veritas Cluster Volume Manager
(CVM) or Cluster File System (CFS).
• Live Application Detach is supported only for modular failover packages and modular multi-node
packages.
◦ You cannot detach legacy packages, but you can halt them and then detach the modular
packages.
◦ You cannot use Live Application Detach if system multi-node packages (such as
SG-CFS-pkg) are configured in the cluster.
Managing the Cluster and Nodes 267