Chapter 7. Monitoring 121
2. Once subscribed, open the Channel Details Packages tab and find the rhnmd package (un-
der ’R’).
3. Click the package name to open the Package Details page. Go to the Target Systems tab, select
the desired systems, and click Install Packages.
4. Install the SSH public key on all client systems to be monitored, as described in Section 7.2.4
Installing the SSH key.
5. Start the Red Hat Network Monitoring Daemon on all client systems using the command:
service rhnmd start
6. When adding probes requiring the daemon, accept the default values for RHNMD User and
RHNMD Port: nocpulse and 4545, respectively.
7.2.3. Configuring SSH
If you wish to avoid installing the Red Hat Network Monitoring Daemon and opening port 4545 on
client systems, you may configure sshd to provide the encrypted connection required between the
systems and RHN. This may be especially desirable if you already have sshd running. To configure
the daemon for monitoring use:
1. Ensure the SSH package is installed on the systems to be monitored:
rpm -qi ssh
2. Identify the user to be associated with the daemon. This can be any user available on the system,
as long as the required SSH key can be put in the user’s ~/.ssh/authorized_keys file.
3. Identify the port used by the daemon, as identified in its /etc/ssh/sshd_config configura-
tion file. The default is port 22.
4. Install the SSH public key on all client systems to be monitored, as described in Section 7.2.4
Installing the SSH key.
5. Start the sshd on all client systems using the command:
service sshd start
6. When adding probes requiring the daemon, insert the values derived from steps 2 and 3 in the
RHNMD User and RHNMD Port fields.
7.2.4. Installing the SSH key
Whether you use rhnmd or sshd, you must install the Red Hat Network Monitoring Daemon public
SSH key on the systems to be monitored to complete the secure connection. To install it:
1. In the RHNwebsite, navigate to theMonitoring
Scout ConfigPush page and click the name
of the RHN Server that will monitor the client system. The SSH id_dsa.pub key is visible on
the resulting page.
2. Copy the character string (beginning with ssh-dss and ending with the hostname of the RHN
Server).
3. On the command line of the system tobe monitored, switch to the user aligned with the daemon.
This is accomplished for rhnmd with the command:
su - nocpulse
4. Paste the key character string into the ~/.ssh/authorized_keys file for the daemon’s user.
For rhnmd, this is /opt/nocpulse/.ssh/authorized_keys.
