IBM SG24-5131-00 User Manual

Page of 240
58
 
IBM Certification Study Guide  AIX HACMP
3.1.4.3  Editing the /etc/hosts File and Nameserver Configuration
Make sure all nodes can resolve all cluster addresses. See the chapter on 
planning TCP/IP networks (the section Using HACMP with NIS and DNS) in 
the 
HACMP for AIX, Version 4.3: Planning Guide, SC23-4277 for more 
information on name serving and HACMP.
Edit the /etc/hosts file (and the /etc/resolv.conf file, if using the nameserver 
configuration) on each node in the cluster to make sure the IP addresses of 
all clustered interfaces are listed.
For each boot address, make an entry similar to the following:
100.100.50.200 crab_boot
Also, make sure that the /etc/hosts file on each node has the following entry:
127.0.0.1   loopback localhost 
3.1.4.4  cron and NIS Considerations
If your HACMP cluster nodes use NIS services, which include the mapping of 
the /etc/passwd file, and IPAT is enabled, users that are known only in the 
NIS-managed version of the /etc/passwd file will not be able to create 
crontabs. This is because cron is started with the /etc/inittab file with run level 
2 (for example, when the system is booted), but ypbind is started in the 
course of starting HACMP with the 
rcnfs
 entry in 
/etc/inittab
. When IPAT is 
enabled in HACMP, the run level of the 
rcnfs
 entry is changed to 
-a
 and run 
with the 
telinit -a
 command by HACMP.
In order to let those NIS-managed users create crontabs, you can do one of 
the following:
  • Change the run level of the 
cron
 entry in 
/etc/inittab
 to 
-a
 and make sure 
it is positioned after the 
rcnfs
 entry in 
/etc/inittab
. This solution is 
recommended if it is acceptable to start cron after HACMP has started.
  • Add an entry to the /etc/inittab file like the following script with run level 
-a
Make sure it is positioned after the 
rcnfs
 entry in /etc/inittab. The important 
thing is to kill the cron process, which will respawn and know about all of 
the NIS-managed users. Whether or not you log the fact that cron has 
been refreshed is optional.