Thursday, 14 July 2011

AIX Files Modified by HACMP

AIX Files Modified by HACMP 

The following AIX files are modified to support HACMP. They are not distributed with HACMP. 

The cluster event scripts use the /etc/hosts file for name resolution. All cluster node IP interfaces must be added to this file on each node.
If you delete service IP labels from the cluster configuration using SMIT, we recommend that you remove them from /etc/hosts too. This reduces the possibility of having conflicting entries if the labels are reused with different addresses in a future configuration.

Note that DNS and NIS are disabled during HACMP-related name resolution. This is why HACMP IP addresses must be maintained locally.

HACMP may modify this file to ensure that all nodes have the necessary information in their /etc/hosts file, for proper HACMP operations.
During installation, the following entry is made to the /etc/inittab file to start the Cluster Communication Daemon at boot: 

clcomdES:2:once:startsrc -s clcomdES >dev/console 2>&1

The /etc/inittab file is modified in each of the following cases: 

HACMP is configured for IP address takeover
The Start at System Restart option is chosen on the SMIT Start Cluster Services panel
Concurrent Logical Volume Manager (CLVM) is installed with HACMP 5.2.
Modifications to the /etc/inittab File due to IP Address Takeover

The following entry is added to the /etc/inittab file for HACMP network startup with IP address takeover:
harc:2:wait:/usr/es/sbin/cluster/etc/ # HACMP network startup

When IP address takeover is enabled, the system edits /etc/inittab to change the rc.tcpip and inet-dependent entries from run level “2” (the default multi-user level) to run level “a”. Entries that have run level “a” are processed only when the telinit command is executed specifying that specific run level.
Modifications to the /etc/inittab File due to System Boot

The /etc/inittab file is used by the init process to control the startup of processes at boot time. The following line is added to /etc/inittab during HACMP install:
clcomdES:2:once:startsrc -s clcomdES >/dev/console 2>&1

This entry starts the Cluster Communications Daemon (clcomd) at boot. 

The following entry is added to the /etc/inittab file if the Start at system restart option is chosen on the SMIT Start Cluster Services panel:
hacmp:2:wait:/usr/sbin/etc/rc.cluster -boot> /dev/console 2>&1 # Bring
up Cluster

When the system boots, the /etc/inittab file calls the /usr/es/sbin/cluster/etc/rc.cluster script to start HACMP.
Because the inet daemons must not be started until after HACMP-controlled interfaces have swapped to their service address, HACMP also adds the following entry to the end of the /etc/inittab file to indicate that /etc/inittab processing has completed:
clinit:a:wait:/bin/touch /usr/es/sbin/cluster/.telinit
#HACMP for AIX These must be the last entry in run level “a” in inittab!
pst_clinit:a:wait/bin/echo Created /usr/es/sbin/cluster/ .telinit >
#HACMP for AIX These must be the last entry in run level “a” in inittab!
The /etc/ file is called by cfgmgr to configure and start TCP/IP during the boot process. It sets hostname, default gateway and static routes. The following entry is added at the beginning of the file for a node on which IP address takeover is enabled:
# HACMP for AIX These lines added by HACMP for AIX software
[ "$1" = "-boot" ] && shift || { ifconfig 1o0 up; exit 0; }

The entry prevents cfgmgr from reconfiguring boot and service addresses while HACMP is running. 

The /etc/services file defines the sockets and protocols used for network services on a system. The ports and protocols used by the HACMP components are defined here.
#clinfo_deadman 6176/tcp
#clm_keepalive 6255/udp
#clm_pts 6200/tcp
#clsmuxpd 6270/tcp
#clm_lkm 6150/tcp
#clm_smux 6175/tcp
#godm 6177/tcp
#topsvcs 6178/udp
#grpsvcs 6179/udp
#emsvcs 6180/udp
#clver 6190/tcp
#clcomd 6191/tcp

Note: The version of snmpd.conf depends on whether you are using AIX 5L v.5.1 or v.5.2. The default version for v.5.2. is snmpdv3.conf.

The SNMP daemon reads the /etc/snmpd.conf configuration file when it starts up and when a refresh or kill -1 signal is issued. This file specifies the community names and associated access privileges and views, hosts for trap notification, logging attributes, snmpd-specific parameter configurations, and SMUX configurations for the snmpd. The HACMP installation process adds the clsmuxpd password to this file. The following entry is added to the end of the file, to include the HACMP MIB managed by the clsmuxpd:
smux "clsmuxpd_password" # HACMP clsmuxpd

HACMP supports SNMP Community Names other than “public.” If the default SNMP Community Name has been changed in /etc/snmpd.conf to something different from the default of “public” HACMP will function correctly. The SNMP Community Name used by HACMP is the first name found that is not “private” or “system” using the lssrc -ls snmpd command.

The Clinfo service also gets the SNMP Community Name in the same manner. The Clinfo service supports the -c option for specifying SNMP Community Name but its use is not required. The use of the -c option is considered a security risk because doing a ps command could find the SNMP Community Name. If it is important to keep the SNMP Community Name protected, change permissions on /tmp/hacmp.out, /etc/snmpd.conf, /smit.log and /usr/tmp/snmpd.log to not be world readable.

The /etc/snmpd.peers file configures snmpd SMUX peers. The HACMP install process adds the following entry to include the clsmuxpd:
clsmuxpd "clsmuxpd_password" # HACMP clsmuxpd


The /etc/syslog.conf file is used to control output of the syslogd daemon, which logs system messages. During the install process HACMP adds entries to this file that direct the output from HACMP-related problems to certain files.
# example:
# "mail messages, at debug or higher, go to Log file. File must exist."
# "all facilities, at debug and higher, go to console"
# "all facilities, at crit or higher, go to all users"
# mail.debug /usr/spool/mqueue/syslog
# *.debug /dev/console
# *.crit *
# HACMP Critical Messages from HACMP
local0.crit /dev/console
# HACMP Informational Messages from HACMP /usr/es/adm/cluster.log
# HACMP Messages from Cluster Scripts
user.notice /usr/es/adm/cluster.log

The /etc/syslog.conf file should be identical on all cluster nodes. 

The /etc/trcfmt file is the template file for the system trace logging and report utility, trcrpt. The install process adds HACMP tracing to the trace format file. HACMP tracing applies to the following daemons: clstrmgr, clinfo, and clsmuxpd.

The /var/spool/cron/crontab/root file contains commands needed for basic system control. The install process adds HACMP logfile rotation to the file.

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