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caad - Cluster Application Availability (CAA) daemon
/usr/sbin/caad [-0] [-1] [-2]
These parameters are used by CAA start and stop scripts only and should not
be used when invoking caad using the command line.
The daemon checks the state specified in the registry for each
application resource on the cluster member and sets the resource state
to OFFLINE. The daemon also checks the state of application resources
for any other cluster members that are down at the time the daemon is
started. This parameter should only be used by the init scripts at boot
Used at startup to notify another running daemon to start application
resources marked for restart in the binary CAA registry database. The
daemon invoked with this parameter exits immediately after
communicating with the running daemon. This parameter should only be
used by the init scripts at boot time.
Used at cluster shutdown by clu_shutdown. The daemon sets a flag in
the CAA registry database for each running application resource for the
application to be started at next boot.
The CAA daemon (caad) monitors CAA resources and keeps CAA-managed
applications highly available by starting, stopping, relocating and
restarting application resources when failure conditions occur. The daemon
is an asynchronous, event-driven process that is started automatically when
the system transitions to boot level 3. It works in conjunction with the
CAA user interface. Do not stop the CAA daemon or the monitoring and
management of CAA-managed applications will be disrupted. This could
jeopardize the availability of CAA-managed applications within the cluster.
A resource profile describes a resource's failover criteria and relocation
requirements. An administrator creates a resource profile for each
resource to be monitored by the CAA daemon. The resource profile can be
created for a network resource, tape resource, media changer resource, or
an application resource. Resource profiles are stored in the
For CAA-managed applications, the resource profile specifies values that
describe how the caad daemon manages the application. This includes, the
placement policy, required resources, hosting members, and other
properties. The profile also specifies the action script that is used to
start, stop, and check the application.
The information in the profile is added to the CAA registry database when a
resource is registered. The CAA daemon can only monitor and manage
Resource monitor files are loaded by the CAA daemon to enable checking on
the state of a particular type of resource. Each resource type has a
seperate resource monitor. Resource monitors are located in the directory
See caa_profile(8) and caa(4) for more information on resource profiles.
Each cluster member runs an instance of the CAA daemon. These instances
run autonomously, but communicate to share cluster and resource state
Upon startup of the cluster system each CAA daemon reads from the registry
database. The CAA daemon determines after reading the registry database the
last state of the cluster and all registered available resources when the
node failed or was shut down.
For all registered application resources not currently running, the CAA
daemon attempts to start these resources and begins monitoring all other
types of resources. How an application resource is started is determined
by the start section of the resource's action script.
Each application resource in the CAA subsystem is under the direct control
of the cluster member currently running. If under any circumstances, the
resource is no longer available due to a member going down, all remaining
CAA daemons in the CAA subsystem arbitrate to take control of the
The caad daemon logs information into the EVM event management system. See
EVM(5) for more information on viewing information in EVM.
The following exit values are returned:
0 Successful completion
A failure has occurred.
Commands: caa_stat(1), caa_profile(8), caa_register(8), caa_relocate(8),
TruCluster Server Cluster Administration
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