IBM RS/6000 SP, Problem Determination Manual

Page: 158 / 316

This soft copy for use by IBM employees only.
Prepare for System Partitioning by setting up an IP alias for each additional
partition that is to be created. The IP alias function is provided in the standard
implementation of TCP/IP in AIX. It allows the association of more than one IP
address with a network interface. For partitioning to work, it is essential that an
alias is created for the interface that is associated with the hostname of the
Control Workstation. To find out the hostname, use the
hostname
command on
the Control Workstation. To find out which interface is associated with the
Control Workstation hostname, run the following command:
# netstat -r | grep <hostname of CWS>
The output of this command will show which interface to create the alias names
for. Typically the interface will either be en0, tr0, or fi0. Following is an example
of how to create an alias for the
en0 network interface:
# ifconfig en0 alias 9.180.6.198 netmask 255.255.255.0 up
Check that the IP alias became associated with the adapter by running the
ping
command. For example:
# ping 9.180.6.198
Ensure that the IP address used is not already in use by another system on the
network. In addition, ensure that there will not be a conflict in the future should
you add any additional nodes. Choose an IP address that will be definitely out of
the range even if you upgrade your RS/6000 SP by adding a large number of
nodes.
The next step is to ensure that the IP alias that has just been set up can be
resolved by the name resolution mechanism. If you are using the /etc/hosts file
for this purpose, then simply add the IP address and an appropriate name.
(These hostnames will be used to identify your partitions when carrying out
system administration tasks on the RS/6000 SP, so bear this in mind when
choosing the names.) Propagate these changes to the nodes either manually by
using
ftp , for example, or by using one of the POWERparallel System Support
Programs commands like
supper
or
pcp
.
If you are using the product Network Information Services (NIS), for example,
ensure that you have a route set up to get to a NIS server from the IP alias
address. Check to see which route is being used for the Control Workstation IP
address so that the same route can be used for the IP alias, should this be
appropriate. Add the aliases to the NIS maps and ensure all slave servers are
updated by running a
yppush
. It is a good idea to have slave servers on the
nodes because if name resolution is not quick and efficient many of the
administrative tools on the RS/6000 SP will not function properly. Following is an
example for adding a route for the alias 9.180.6.198:
# route add -net 9.180.3.0 netmask 255.255.255.0 9.180.6.198
Check that name resolution is working for the aliases by running:
# host <alias name>
In addition, ensure that the IP alias is persistent after a system reboot by adding
the details of the
ifconfig
described previously, to the rc.net file so that it will
run each time from the /etc/inittab.
If name resolution is not working, the following steps will not be successful when
the attempt is made to set up System Partitioning. Resolve the network
problems at this stage and only then continue setting up the partitions.
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SP PD Guide