Most annoying thing about Docker’s swarm mode

The most annoying thing about running a Docker swarm — something that for the most part was pretty easy to set up and get going, has to be the flood of log messages that dockerd generates.

According to this issue of github, fixing it “will require a code change, at the moment not being a breaking issue that creates traffic disruption is not getting much priority.”

So, I had to dig around in a part of Linux admin I had not touched in year: rsyslog. It was actually pretty simple to squelch these log messages, thanks to this page.

I use Ubuntu, and the fix is to add the following to the start of /etc/rsyslog.d/50-default.conf: :msg, contains, "Node join event" ~. After that, a sudo service rsyslog restart and, blammo, no more log spam on the swarm master nodes.