Managing HP Serviceguard for Linux Ninth Edition, April 2009

NOTE: If such a hang or error occurs, Serviceguard and all protected applications
will continue working even though the command you issued does not. That is, only
the Serviceguard configuration commands (and corresponding Serviceguard Manager
functions) are affected, not the cluster daemon or package services.
The procedure that follows shows how to create a robust name-resolution configuration
that will allow cluster nodes to continue communicating with one another if a name
service fails.
1. Edit the /etc/hosts file on all nodes in the cluster. Add name resolution for all
heartbeat IP addresses, and other IP addresses from all the cluster nodes; see
“Configuring Name Resolution” (page 150) for discussion and examples.
NOTE: For each cluster node, the public-network IP address must be the first
address listed. This enables other applications to talk to other nodes on public
networks.
2. If you are using DNS, make sure your name servers are configured in /etc/
resolv.conf, for example:
domain cup.hp.com
search cup.hp.com hp.com
nameserver 15.243.128.51
nameserver 15.243.160.51
3. Edit or create the /etc/nsswitch.conf file on all nodes and add the following
text (on one line), if it does not already exist:
• for DNS, enter (one line):
hosts: files [NOTFOUND=continue UNAVAIL=continue] dns [NOTFOUND=return UNAVAIL=return]
• for NIS, enter (one line):
hosts: files [NOTFOUND=continue UNAVAIL=continue] nis [NOTFOUND=return UNAVAIL=return]
If a line beginning with the string “hosts:” already exists, then make sure that
the text immediately to the right of this string is (on one line):
files [NOTFOUND=continue UNAVAIL=continue] dns [NOTFOUND=return UNAVAIL=return]
or
files [NOTFOUND=continue UNAVAIL=continue] nis [NOTFOUND=return UNAVAIL=return]
This step is critical, allowing the cluster nodes to resolve hostnames to IP addresses
while DNS, NIS, or the primary LAN is down.
4. Create a $SGCONF/cmclnodelist file on all nodes that you intend to configure
into the cluster, and allow access by all cluster nodes. See “Allowing Root Access
to an Unconfigured Node” (page 149).
152 Building an HA Cluster Configuration