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Recca Tsai
Recca Tsai

Posted on • Originally published at recca0120.github.io

Overmind: Managing Multiple Local Services Better Than foreman

#overmind #tmux #procfile #rails

Originally published at recca0120.github.io

Running a full-stack Rails project locally means at least four services: Rails server, Sidekiq, frontend build, and CSS watch. The old approach was four terminal tabs or foreman to bundle them together.

After using foreman for a while, a few things got to me: log colors disappearing, output delayed by several seconds, and one dying process taking down everything else. Overmind fixes all of this — and adds a few features that become hard to live without.

What Is a Procfile

Overmind reads a Procfile, a format popularized by Heroku that defines which services your application provides and what commands to run them:

web: bin/rails server
worker: bundle exec sidekiq
assets: yarn build --watch
css: yarn tailwind --watch
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One line per service, format is name: command. This file also works as deployment config on Heroku, Render, and Railway — same file locally and in production, fewer environment mismatches.

Installation

On macOS, install tmux first (Overmind's core dependency):

brew install tmux
brew install overmind
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On Linux:

apt-get install tmux
# Download the latest release binary, or:
go install github.com/DarthSim/overmind/v2@latest
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Basic Usage

In any directory containing a Procfile:

overmind start
# or the short alias
overmind s
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All services start up with their log output collected in one stream, each process name color-coded.

Features That Make the Difference

Restart a Single Process

I use this daily. After changing a Sidekiq worker, I don't need to stop and restart the whole stack:

overmind restart worker
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Only worker restarts. Web and frontend build keep running uninterrupted.

Connect to a Process

Need to interact with a process directly — check output or type a command:

overmind connect web
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This opens a tmux window attached to that process. Press Ctrl+b d to detach without stopping it.

Let a Process Die Without Killing Others

A frontend build that exits when done shouldn't tear down the whole stack:

overmind start -c assets,npm_install
# or via env var
OVERMIND_CAN_DIE=assets,npm_install overmind start
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Auto-restart

For processes that occasionally crash:

overmind start -r worker
OVERMIND_AUTO_RESTART=worker overmind start
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Use all to auto-restart everything:

overmind start -r all
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Why Logs Don't Get Clipped or Delayed

foreman's log issues come from how processes detect their output destination. When a program's stdout isn't a real terminal, it switches to buffered mode — color escape codes get stripped and output batches until the buffer fills.

Overmind runs each process in a real tmux window and uses tmux's control mode to capture output. From the process's perspective it's writing to a terminal, so colors stay intact and output is immediate.

Environment File Configuration

Rather than typing long flags every time, create .overmind.env in your project:

OVERMIND_PORT=3000
OVERMIND_AUTO_RESTART=worker
OVERMIND_CAN_DIE=assets
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Overmind reads this automatically on start. You can also put global settings in ~/.overmind.env.

Port Assignment

Overmind sets the PORT env variable for each process automatically:

  • First process: PORT=5000
  • Second: PORT=5100
  • And so on (step defaults to 100)

Use it in your Procfile:

web: bin/rails server -p $PORT
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Change the base port:

overmind start -p 3000
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Reference another process's port:

web: bin/rails server -p $PORT
proxy: ngrok http $OVERMIND_PROCESS_web_PORT
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Running Only Some Services

When you only need web and worker, not the frontend build:

# Run only specified services
overmind start -l web,worker

# Exclude specified services
overmind start -x assets,css
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Scaling

Run multiple instances of a process:

overmind start -m web=1,worker=3
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Three worker instances start with ports assigned sequentially.

foreman vs Overmind

Feature foreman Overmind
Basic Procfile support ✓ ✓
Log color preservation Often broken Works correctly
Real-time log output Buffered Immediate
Restart single process ✗ ✓
Connect to process ✗ ✓
Can-die processes ✗ ✓
Auto-restart ✗ ✓
Dependency None tmux

The main tradeoff is the tmux dependency. If tmux isn't available or you only need basic Procfile management, the same author built Hivemind — no tmux integration, but no log problems either.

A Real Procfile Example

Rails + Sidekiq + Vite:

web: bin/rails server -p $PORT
worker: bundle exec sidekiq -C config/sidekiq.yml
vite: bin/vite dev
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With .overmind.env:

OVERMIND_PORT=3000
OVERMIND_AUTO_RESTART=worker
OVERMIND_CAN_DIE=vite
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Start everything:

overmind s
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Three services, each in their own tmux window, colors intact, worker auto-restarts on crash, vite can exit without taking down the rest.

References

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