### Nagios Host IP Update ###
The Nagios hosts looks down need to update their IPs

For our example, we take `app_flink_master`, his IP is 10.60.2.232 which need to be updated.

On AWS EC2 we can search for `flink`. There are 3 `neuro-flink-master-server-resources-app` 3 are **Running** and other 3 are **Terminated**. These are our hosts.

In the GitLab project [dev/nagiosconfig](http://gitlab.pglabs.co.uk/dev/nagiosconfig) we should edit the file [`servers/flink.cfg`](http://gitlab.pglabs.co.uk/dev/nagiosconfig/-/blob/master/servers/flink.cfg) via Web IDE.
Scroll dow to the line `define host` where the `host_name` is `app_flink_master` you should see the address is pointing to the old IP.

Change the old IP with the new IP on the hosts that appears down in Nagios.
Once you have done updating the IPs, click on **Create Commit**, write a comment and **Commit** again.

Now we need to ssh to the Nagios server.
```
ssh -i "neuroProd2021.pem" ubuntu@10.0.14.194
```
Move to `/usr/local/nagios/etc` pull the new config `sudo git pull origin master` and restart the service `sudo service nagios restart`.

The hosts will show UP again.