Monit配置咨询：同一命令进程数超1时如何触发告警？

云上老周

2026-5-21

Absolutely feasible! Monit was built for exactly this kind of process monitoring task—catching orphaned Sidekiq processes after a Capistrano deploy is a perfect use case. Let’s walk through how to set this up properly:

Step 1: Add a Custom Process Check to Your Monit Config

You’ll need to define a check that targets your Sidekiq processes and triggers an alert when their count exceeds 1. First, identify the unique command string that identifies your Sidekiq workers (this should be consistent across your deployments). For most Capistrano setups, this might look something like /home/deploy/your_app_name/current/bin/sidekiq.

Add this block to your Monit configuration file (usually located at /etc/monit/monitrc or in a separate file under /etc/monit/conf.d/):

check process sidekiq_orphan_check
  matching "/home/deploy/your_app_name/current/bin/sidekiq"
  # Optional: Restrict to a specific user if needed (e.g., your deploy user)
  as uid deploy
  # Trigger alert when more than 1 matching process is found
  if number of processes > 1 then alert

Step 2: Refine the Process Matching (If Needed)

If you run multiple legitimate Sidekiq processes (e.g., for different queues or environments), you’ll need to narrow down the matching rule to target only the orphaned ones from your main deployment. For example, if your Sidekiq command includes a queue name like queue=default, adjust the match string:

matching "/home/deploy/your_app_name/current/bin/sidekiq.*queue=default"

You can test your match logic manually first with a command like:

ps aux | grep "/home/deploy/your_app_name/current/bin/sidekiq" | grep -v grep

This should return only the processes you want to monitor.

Step 3: Test and Activate the Config

Before reloading Monit, validate your configuration to catch syntax errors:

monit -t

If you see Control file syntax OK, reload Monit to apply the changes:

monit reload

You can verify the check is active by running:

monit status sidekiq_orphan_check

Bonus: Customize Alert Notifications

Monit supports sending alerts via email, Slack, or other channels. If you haven’t already, configure your notification settings in the main monitrc file to ensure you get notified when the threshold is hit.

内容的提问来源于stack exchange，提问作者pragmatic_programmer