HP XC System Software Administration Guide Version 3.1

For additional information, see pdsh(1). You can also find additional information at the following Web
site:
http://www.llnl.gov/linux/pdsh/
1.3.3.2 Using the cexec Command
The cexec command provides the same facility as the pdsh command plus two additional features:
• The cexec command provides an additional option, which enables you to specify a host group or a
service group:
— A host group is a designated list of nodes.
— A service group is a list of nodes and the services that are configured to run on them.
• The output of the cexec command is logged as an event, but the output of the pdsh command is
not.
The format of this command is:
cexec -[options] " command ... "
Important:
Do not pass a command that requires interaction as an argument to the cexec command. Prompting from
the remote node can cause the command to hang.
Useful command options include the following:
Targets all nodes.
-a
Runs the remote commands as the specified user.
-lusername
Sets a list of target nodes.
-wnodename,...
Sets a list of target nodes to be excluded.
-xnodename,...
The following example runs the users command on all the nodes in a four-node system:
# cexec -a "users"
n4: root db dal guest
n3: cjg
n2: rc wk
n1: root tcr
The following example runs the who --count command on nodes n12 and n25:
# cexec -a "who --count"
n12: root bg rmk
n12: # users=3
n25: root wra guest spg
n25: # users=4
For additional information, see cexec(1).
1.4 Configuration and Management Database
The HP XC system stores information about the nodes and system configuration in the configuration and
management database (CMDB). This is a MySQL database that runs on the node with the node management
role. The CMDB is constructed during HP XC system installation. It contains data on hardware and
software configuration and on the connectivity of the system.
The configuration parameters stored in the CMDB include:
• Node names
• Server types
• Memory
34 HP XC Administration Environment