For those of us who use the popular distributed job queueing system Sidekiq, it’s a common problem: a Sidekiq instance containing a pool of workers dies, and the only way you find out about the problem is by checking the Sidekiq dashboard and seeing that you’ve got a ton of jobs backed up and fewer busy workers than expected. Luckily, there’s an easy way to get email alerts when one of your instances goes down, using Dead Man’s Snitch and a little bit of code inspired by the sidekiq\_snitch gem.