View Your App's Dynos
Last updated December 03, 2024
Table of Contents
This article describes how to view the list of dynos in your app and what you can use dyno identifiers for.
Dyno Identifiers and Uses
Each running dyno has an identifier that includes its process type in it. For Cedar-generation apps, identifiers appear as process.X, for example, web.1. For Fir-generation apps, identifiers appear as process-X-Y, for example, web-12a34bcd56-7efgh.
In the examples used in this article, the app has two web dynos with identifiers of web.1 and web.2 and one worker dyno, worker.1.
You can use this identifier to do things like:
- filter your app’s logs by its dyno identifier
- inspect a specific dyno by tunneling with Heroku Exec
- restart a specific dyno by CLI or API
View Your List of Dynos
With the Heroku CLI
You can see your dyno formation with the heroku ps command:
$ heroku ps -a example-app
=== web (Standard-2X): `bundle exec unicorn -p $PORT -c ./config/unicorn.rb`
web.1: up for 8h
web.2: up for 3m
=== worker (Standard-1X): `bundle exec stalk worker.rb`
worker.1: up for 1m
In this example, the app has two web Standard-2X dynos and one worker Standard-1X dyno running. The info also shows the start command for the web and worker processes.
You can also use the Unix watch utility in combination with the ps command. Run watch heroku ps in one terminal while you add or remove dynos, deploy, or restart your app.
With the Heroku API
Use the Formation List API call to retrieve your list of dynos.