Managing HP Serviceguard A.11.20.10 for Linux, December 2012

NOTE: Setting the failback_policy to automatic can result in a package failback and
application outage during a critical production period. If you are using automatic failback, you
may want to wait to add the package’s primary node back into the cluster until you can allow the
package to be taken out of service temporarily while it switches back to the primary node.
Serviceguard automatically chooses a primary node for a package when the NODE_NAME is set
to '*'. When you set the NODE_NAME to '*' and the failback_policy is automatic, if you
add, delete, or rename a node in the cluster, the primary node for the package might change
resulting in the automatic failover of that package.
3.3.1.2.7 On Combining Failover and Failback Policies
Combining a failover_policy of min_package_node with a failback_policy of
automatic can result in a package’s running on a node where you did not expect it to run, since
the node running the fewest packages will probably not be the same host every time a failover
occurs.
3.3.2 Using the Generic Resources Monitoring Service
Generic Resources module is a resource monitoring mechanism in Serviceguard that allows you
to monitor critical resources for a package. It provides integration of custom, user-defined monitors
in Serviceguard by configuring generic resources as part of package configuration. With generic
resources different kind of monitoring mechanisms, such as Custom monitors can be used and
these can co-exist in a single package.
Generic resources has the following advantages:
• Custom defined monitors can also be integrated
• Provides better control, options, and flexibility in terms of getting and setting the status of a
resource
Generic resources can be configured into any modular style package. They can be configured for
failover or multi-node packages and are included in modular failover packages by default. A single
resource can be specified across multiple packages.
You can either generate a new package configuration file containing the generic resource
parameters or add the module to an existing package to include the generic resource parameters.
When you generate a package with the generic resource module, Serviceguard provides the
following parameters for configuring generic resources:
• generic_resource_name
• generic_resource_evaluation_type
• generic_resource_up_criteria
You can then configure generic resources using these parameters. For details on the parameters,
see “Package Parameter Explanations” (page 168) and the cmmakepkg (1m) manpage. For steps
to configure a generic resources, see “Configuring a Generic Resource” (page 104).
You can also add, delete, or modify generic resources depending on certain conditions. For
information, see “Online Reconfiguration of Generic Resources” (page 107).
Monitoring of these resources takes place outside of the Serviceguard environment. These are done
by writing monitoring scripts that can be launched either within the Serviceguard environment by
configuring them as services, or outside of Serviceguard environment.
These scripts are written by end-users and must contain the core logic to monitor a resource , and
the status of the generic resource set accordingly using cmsetresource(1m). These are started
as part of package start and will continue to run until package services are halted. For more
information, see “Monitoring Script for Generic Resources” (page 289).
50 Understanding Serviceguard Software Components