At work, we're in the process of moving datacentres and some of my (extensive) monitoring needs to be updated. In particular, I have a monitor on Hadoop jobs which looks for job names of a specific pattern and posts them to a TeamUp calendar so that we can see what's running where. Over the weekend, the old datacentre's Hadoop job-trackers were shut down - now my monitor is complaining that it can't connect.

The datacentre migration does not have a central documentation location showing the URLs of old and new (for reasons I cannot understand, the ops people decided to change the hostnames in a way that does not allow for any kind of mapping from old to new), so now I need to find the server running the job-tracker in the new datacentre. The main clue I had is that it's running on port 50030.

nmap -p 50030 10.xxx.yyy.0/24 |\
 grep -B4 "50030/tcp open"

Luckily, nmap is still available, and I have an account on a server in the datacentre, so the hardest part was removing the nmap entries for servers where the port was closed: the grep.

Wed 2018-02-28

unix nmap