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How to configure a "passive" poller to work behind NAT

This procedure is partly supported Copied

Articles in the “Unsupported Community Documents” space are normally not supported by ITRS support. This procedure is used for slim pollers, but we recommend avoiding it if possible for regular pollers.

This how-to will describe how to configure a “passive” poller that is located behind a NAT firewall where port forwarding is not possible. This is called running a passive poller. Running multiple poller nodes behind the very same NAT is not supported ? two nodes must not be seen at the same IP address, in the master’s point of view.

Prerequisites In this example we have a master server called master01 and a poller called nat_poller that is behind a firewall.

• The master server must be accessible on port 22 and 15551 from the poller.
• Basic understanding of op5 Monitor with master-peer configuration

Steps Copied

Important information in case of peered masters Copied

If you have more than one master in your environment, the steps below that relates to “master01” also need to be performed on the peered master. You also need to “mon node add” the peered master.

1. On master01, edit the /etc/hosts file using your favorite text editor, and map the hostname nat_poller to the outgoing NAT IP address of nat_poller (i.e. the IP address which the poller will connect from in the master’s point of view). Example:

   192.0.2.34 nat_poller
   

2. On master01, set up the poller node nat_poller by executing the command below.

   mon node add nat_poller type=poller hostgroup=nat_poller
   

3. On master01, edit the /opt/monitor/op5/merlin/merlin.conf configuration file, and insert takeover = no andconnect = no into the nat_poller configuration block. Example:

   poller nat_poller {
       address = nat_poller
       port = 15551
       hostgroup = nat_poller
       connect = no
       takeover = no
   }
   

4. On nat_poller, set up the master node master01 by executing the command below.

   mon node add master01 type=master
   

5. On nat_poller, edit the /opt/monitor/op5/merlin/merlin.conf configuration file, and insert into the master01 configuration block: a sub-block called object_config, containing fetch_name and fetch settings. Example:

   master master01 {
       address = master01
       port = 15551
       object_config {
           fetch_name = nat_poller
           fetch = mon oconf fetch master01
       }
   }
   

   The value of the fetch_name setting should be set to the name of the poller.

6. On nat_poller, disable any default nagios object configuration files by executing the command below.

   sed -i /^cfg_file=/d /opt/monitor/etc/nagios.cfg
   

7. On nat_poller, verify and set up SSH connectivity by executing the command below.

   mon sshkey push --all
   

8. On master01, restart the op5 Monitor system services by executing the command below.

   mon restart
   

9. On nat_poller, fetch the new configuration from master01 by executing the command below.

   asmonitor mon oconf fetch master01