# RAC Attack - Oracle Cluster Database at Home/Clusterware Callouts

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* Clusterware and Fencing
* Clusterware Callouts
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The goal of this lab is to demonstrate Oracle Fast Application Notification (FAN) Callouts. In versions prior to 11g, these were also known as Oracle Clusterware Callouts.
This feature is a relatively little-known capability for Oracle Clusterware to fire a script (or a whole directory full of them) to perform whatever tasks you may want performed when a cluster-wide event happens.
For more information, consult the documentation here: http://download.oracle.com/docs/cd/B28359_01/rac.111/b28254/hafeats.htm#BABGCEBF
For this exercise, we’ll configure some FAN callout scripts on each node and then trigger various cluster events to see how each one triggers the callout script.
* Start with a normal, running cluster with both nodes up and running.
* From a shell prompt (logged in as oracle) on each server, navigate to /u01/grid/oracle/product/11.2.0/grid_1/racg/usrco. Create file there called callout1.sh using vi (or your favorite editor). The contents of the file should be this: #!/bin/ksh umask 022 FAN_LOGFILE=/tmp/`hostname`_uptime.log echo $* "reported="`date` >> $FAN_LOGFILE & Note the use of backticks around the hostname and date commands.
* Make sure that the permissions on the file are set to 755 using the following command: [oracle@<node_name> ~]$ chmod 755 \ > /u01/grid/oracle/product/11.2.0/grid_1/racg/usrcocallout1.sh
* Monitor the logfiles for clusterware on each node. On each node, start a new window and run the following command: [oracle@<node_name> ~]$ tail –f \ /u01/grid/oracle/product/11.2.0/grid_1/log/`hostname -s`/crsd/crsd.log
* Next, we need to trigger an event that will cause the callout to fire. One such event is node shutdown. Shutdown the clusterware on node collabn2. [root@collabn2 ~]# crsctl stop crs Stopping resources. This could take several minutes. Successfully stopped Oracle Clusterware resources Stopping Cluster Synchronization Services. Shutting down the Cluster Synchronization Services daemon. Shutdown request successfully issued.
* Following this command, watch the logfiles you began monitoring in step 2 above. Because we set long timeouts on our test cluster, you might have to wait for a few minutes before you see anything. You should see these messages in the /tmp/*.log files: NODE VERSION=1.0 host=collabn2 incarn=0 status=nodedown reason=public_nw_down timestamp=30-Aug-2009 01:56:12 reported=Sun Aug 30 01:56:13 CDT 2009 NODE VERSION=1.0 host=collabn2 incarn=147028525 status=nodedown reason=member_leave timestamp=30-Aug-2009 01:57:19 reported=Sun Aug 30 01:57:20 CDT 2009
** You should eventually observe entries noting that the node has failed and shortly following that, you should observe an entry placed in the /tmp/<hostname>_uptime.log file indicating that the node is down.
** Note which members run the clusterware callout script. (A surviving member could run commands to notify clients and/or application servers that one of the cluster nodes has died.)
* Restart the clusterware. Is there a node up event? [root@collabn2 bin]# crsctl start crs
* Try powering off one of the virtual machines – is there an difference from the previous test? What if you disable a linux network interface or VMware network card?
* You may conduct more testing, if you wish. Another interesting event is a database instance going down unexpectedly. Come back to this lab after installing a database to test that situation. [oracle@collabn2 ~]$ sqlplus "/ as sysdba" SQL*Plus: Release 11.1.0.6.0 - Production on Fri Aug 1 14:49:29 2008 Copyright (c) 1982, 2007, Oracle. All rights reserved. Connected to: Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - Production With the Partitioning, Real Application Clusters, OLAP, Data Mining and Real Application Testing options SQL> shutdown abort; ORACLE instance shut down. SQL> INSTANCE VERSION=1.0 service=RAC.vm.ardentperf.com database=RAC instance=RAC2 host=collabn2 status=down reason=user timestamp=01-Aug-2008 12:34:02 reported=Fri Aug 1 12:34:03 CDT 2008