Managing HP Serviceguard for Linux, Seventh Edition, July 2007

Understanding Serviceguard Software Components
How Packages Run
Chapter 3 61
Before the Control Script Starts
First, a node is selected. This node must be in the package’s node list, it
must conform to the package’s failover policy, and any resources required
by the package must be available on the chosen node. One resource is the
subnet that is monitored for the package. If the subnet is not available,
the package cannot start on this node. Another type of resource is a
dependency on another package. If monitoring shows a value for a
configured resource that is outside the permitted range, the package
cannot start.
Once a node is selected, a check is then done to make sure the node
allows the package to start on it. Then services are started up for a
package by the control script on the selected node. Strictly speaking, the
run script on the selected node is used to start a legacy package; the
master control script starts a modular package.
During Run Script Execution
Once the package manager has determined that the package can start on
a particular node, it launches the script that starts the package (that is, a
package’s control script or master control script is executed with the
start parameter). This script carries out the following steps:
1. Executes any external_pre_scripts (modular packages only; see
“About External Scripts” on page 122)
2. Activates volume groups or disk groups.
3. Mounts file systems.
4. Assigns package IP addresses to the LAN card on the node (failover
packages only).
5. Executes any customer-defined run commands (legacy packages
only; see “Adding Customer Defined Functions to the Package
Control Script” on page 269) or external_scripts (modular
packages only; see page 122).
6. Starts each package service.
7. Exits with an exit code of zero (0).