Resource Group (Service) Manager
Running under CMAN (and using the DLM), rgmanager manages and provides failover capabilities for collections of resources called services, resource groups, or resource trees in a cluster. These resource groups are tree-structured, and have parent-child dependency and inheritance relationships within each subtree.
There are many resource types provided with rgmanager; the most important being the service resource type. The service resource type is more or less a container resource type. It has two primary purposes:
- provide a link between cluster.conf and rgmanager's placement policy
- provide ordering guarantees for children based on resource type
For a full list of resource types available with rgmanager, check here.
Service How-To Documents
FailoverDomains - How rgmanager's failover domains work
ResourceTrees - How rgmanager's resource trees work, including start/stop orders and inheritance
LVMFailover - Failover of a volume group without Clustered Logical Volume Management
EventScripting - If rgmanager's failover & recovery policies are not enough for you, write your own!
SambaFailover - Failover of a Samba share
OCF RA API Draft - How resource agents are (supposed to) work
rgmanager mostly implements this, but does not correctly call monitor. Instead, it calls status.
MultipleInstanceServices - If you want to run the same thing on many nodes, here's how.
Oracle Database 10g Release 2 information and resource agent
Logging Configuration
rgmanager configuration
Rgmanager may be configured for various log levels using different syslog facilities.
Using cluster.conf:
<rm log_level="..." log_facility="..." ... >
log_level is a number from 0..7, where 7 is 'debug' and 0 is 'emergency only'. The default value is 4.
log_facility is a string containing a facility name, such as daemon, local4, or similar. Possible values for this are described in syslog.conf(5) manual page in the section entitled SELECTORS. The default value is daemon.
Using the init script (which references /etc/sysconfig/cluster). Add the following to enable debug log level to /etc/sysconfig/cluster:
RGMGR_OPTS="-d"
This is the same as changing log_level to 7
syslog configuration
It may be desirable to redirect rgmanager's logging messages to a different file (instead of /var/log/messages). In order to do this, place a line like the following in /etc/syslog.conf and restart syslog:
local4.* /var/log/rgmanager
(The former assumes you have set log_facility to local4 in cluster.conf; the default is daemon. For more information, see the manual page for syslog.conf(5).
RIND Configuration
RIND is not dependencies. TBD.
Links
http://www.clusterlabs.org/mw/Install - Installation guide for Pacemaker, a proposed replacement for rgmanager.