Managing HP Serviceguard A.11.20.00 for Linux, June 2012

Online Reconfiguration of Generic Resources
Online operations such as addition, deletion, and modification of generic resources in packages
are supported. The following operations can be performed online:
• Addition of a generic resource of generic_resource_evaluation_type set to
during_package_start, whose status is not down.
Please ensure that while adding a generic resource, the equivalent monitor is available; if not
add the monitor while adding a generic resource.
• Addition of a generic resource of generic_resource_evaluation_type set to
before_package_start, whose status is 'up'.
• Deletion of a generic resource. Please ensure that while deleting a generic resource, the
equivalent monitor is also removed. However, if a common resource is being monitored across
multiple packages, then before removing the monitor ensure that the generic resource being
deleted is not configured in other packages that are also using this monitor.
• Modification of generic_resource_evaluation_type from before_package_start
to during_package_start or vice versa when the resource is 'up'.
• Modification of generic_resource_up_criteria specified for resources of evaluation
type before_package_start or during_package_start provided the new up criteria
does not cause the resource status to evaluate to 'down' (i.e., the current_value of the resource
still satisfies the new up_criteria).
• Modification of resource type from a simple resource to an extended resource is allowed only
if the generic_resource_evaluation_type is during_package_start in all the
running packages that currently use the resource.
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 163).
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 105). You should read the next section,
“Simple Dependencies” (page 100), first.
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 163). For a discussion of complex dependencies, see
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 104) that follow.
Rules for Simple Dependencies
Assume that we want to make pkg1 depend on pkg2.
100 Planning and Documenting an HA Cluster