Managing HP Serviceguard A.11.20.20 for Linux, March 2014

Limitations
Following are the limitations with new behavior of online reconfiguration for serviceguard-xdc
packages:
• Cannot add and delete an MD device simultaneously.
• Cannot add an MD device and replace a mirror half in another existing MD device
simultaneously.
• Cannot delete an MD device and replace a mirror half in another existing MD device
simultaneously.
• Cannot replace multiple mirror halves simultaneously while the package is running.
4.8.7 About Package Dependencies
A package can have dependencies on other packages, meaning the package will not start on a
node unless the packages it depends on are running on that node.
You can make a package dependent on any other package or packages running on the same
cluster node, subject to the restrictions spelled out in Chapter 6, under “dependency_condition”
(page 180).
Serviceguard adds two new capabilities: you can specify broadly where the package depended
on must be running, and you can specify that it must be down. These capabilities are discussed
later in this section under “Extended Dependencies” (page 117). You should read the next section,
“Simple Dependencies” (page 113), first.
4.8.7.1 Simple Dependencies
A simple dependency occurs when one package requires another to be running on the same node.
You define these conditions by means of the parameters dependency_condition and
dependency_location, using the literal values UP and same_node, respectively. (For detailed
configuration information, see the package parameter definitions starting with “dependency_name”
(page 180). For a discussion of complex dependencies, see “Extended Dependencies” (page 117).
Make a package dependent on another package if the first package cannot (or should not) function
without the services provided by the second. For example, pkg1 might run a real-time web interface
to a database managed by pkg2. In this case it might make sense to make pkg1 dependent on
pkg2.
In considering whether or not to create a dependency between packages, use the Rules for Simple
Dependencies and Guidelines for Simple Dependencies (page 117) that follow.
4.8.7.2 Rules for Simple Dependencies
Assume that we want to make pkg1 depend on pkg2.
NOTE: pkg1 can depend on more than one other package, and pkg2 can depend on another
package or packages; we are assuming only two packages in order to make the rules as clear as
possible.
4.8 Package Configuration Planning 113