Graphs showing spikes at Linode
#145 Henry, Tuesday, 12 June 2012 10:08 PM (Category: Network)
(Tags: linode spamassassin)

I kept noticing some small issues. Linode provide some nifty graphs so you can track your system usage. I kept noticing spikes in all the graphs. I ignored them while I was getting the system going, but eventually when everything was running, I had to deal with them.

So when I saw one of these spikes, or when they emailed me about spiked CPU usage, I would look at top and I would see that inetd was showing 20% CPU usage and would stick at it for ever. If I restarted inetd, usage would drop to 0%, but in a few hours it would top out again.

I went and looked in /var/logs to see if I could see anything, and oh yes, I could see something. I noticed that syslog was 2,042,420,739 bytes big. A quick scroll through it showed massive amounts of these logs:

Jun 10 15:12:50 moshie inetd[27936]: execv /usr/sbin/in.identd: No such file or directory
Jun 10 15:12:50 moshie inetd[1331]: /usr/sbin/in.identd: exit status 0x1

Over and over and over again.

I looked for in.identd and it's not on my system. I checked /etc/inetd.conf.

When SpamAssassin is checking stuff, it does an AUTH lookup. It goes through inetd which attempts to spawn /usr/sbin/in.identd, but it's not there so it tries again and again and again, with no waits or sleeps. It writes a couple of logs each time. So inetd runs the CPU into the ground trying to spawn this program, the /var/log/syslog file gets bigger and bigger. It's a disaster chewing up resources until I notice it and kill it.

I looked up the package that in.identd should be in - pidentd - and I used to slackpkg to install it. And that fixed that problem.