Managing Serviceguard Nineteenth Edition, Reprinted June 2011

If a monitored resource is configured in a package, the package manager calls the resource
registrar to launch an external monitor for the resource. Resources can be configured to start up
either at the time the node enters the cluster or at the end of package startup. The monitor then
sends messages back to Serviceguard, which checks to see whether the resource is available
before starting the package. In addition, the package manager can fail the package to another
node or take other action if the resource becomes unavailable after the package starts.
You can specify a monitored resource for a package in Serviceguard Manager, or on the HP-UX
command line by using the command /opt/resmon/bin/resls. For additional information,
see the manpage for resls(1m).
Using the EMS HA Monitors
The EMS (Event Monitoring Service) HA Monitors, available as a separate product, can be used
to set up monitoring of disks and other resources as package resource dependencies. Examples
of resource attributes that can be monitored using EMS include the following:
• Logical volume status
• Physical volume status
• System load
• Number of users
• File system utilization
• LAN health
Once a monitor is configured as a package resource dependency, the monitor will notify the
package manager if an event occurs showing that a resource is down. The package may then be
failed over to an adoptive node.
The EMS HA Monitors can also be used to report monitored events to a target application for
graphical display or for operator notification. For more information, see the latest Event Monitoring
Service release notes and other documents at http://www.hp.com/go/hpux-ha-monitoring-docs.
See also “Using EMS to Monitor Volume Groups” (page 96).
How Packages Run
Packages are the means by which Serviceguard starts and halts configured applications. Failover
packages are also units of failover behavior in Serviceguard. A package is a collection of services,
disk volumes and IP addresses that are managed by Serviceguard to ensure they are available.
There can be a maximum of 300 packages per cluster and a total of 900 services per cluster.
What Makes a Package Run?
There are 3 types of packages:
• The failover package is the most common type of package. It runs on one node at a time. If
a failure occurs, it can switch to another node listed in its configuration file. If switching is
enabled for several nodes, the package manager will use the failover policy to determine
where to start the package.
• A system multi-node package runs on all the active cluster nodes at the same time. It can be
started or halted on all nodes, but not on individual nodes.
• A multi-node package can run on several nodes at the same time. If auto_run is set to yes,
Serviceguard starts the multi-node package on all the nodes listed in its configuration file. It
can be started or halted on all nodes, or on individual nodes, either by user command
(cmhaltpkg) or automatically by Serviceguard in response to a failure of a package
component, such as service, EMS resource, or subnet.
System multi-node packages are supported only for use by applications supplied by Hewlett-Packard.
56 Understanding Serviceguard Software Components