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Dokku (container)

Paas

Dokku setup as a container

Image details

Pulls: 420k
Architecture: amd64, arm64, arm/v7
Image size: 568 MB
Latest: 0.38.27
User: dokku
Created: Aug 07, 2019
Updated: 3 days ago
Status: active

Source details

Repo: dokku/dokku
Stars: 32.1k
Forks: 2k
Language: Shell
License: MIT
Latest: v0.38.27 · 3 days ago
Updated: 2 days ago
Website: dokku.com/

Configuration

Type
Container
Platform
linux
Image
dokku/dokku
Ports
22/tcp80/tcp443/tcp
Volumes
/mnt/dokku : /var/lib/dokku/var/run/docker.sock : /var/run/docker.sock
Env vars
DOKKU_HOSTNAME=''DOKKU_HOST_ROOT=/var/lib/dokku/home/dokku

Template by portainer

Standalone Install

Select an install method, to see config/commands for deploying Dokku (container)

Installation method

Install on Portainer

Import all app templates into your Portainer instance, for easy 1-click deploys

  1. Ensure both Docker and Portainer are installed, and up-to-date
  2. Log into your Portainer web UI
  3. Under Settings → App Templates, paste the below URL
  4. Head to Home → App Templates, and the list of apps will show up
  5. Select Dokku (container), fill in any config options, and hit Deploy

Template Import URL

https://raw.githubusercontent.com/Lissy93/portainer-templates/main/templates.json
Show Me demo

More install options in our documentation, or see dokku/dokku for app-specific guidance.

Docker Installation Notes

Pull the dokku/dokku image:
docker pull dokku/dokku:latest

Next, run the image.
docker run \
  --env DOKKU_HOSTNAME=dokku.me \
  --name dokku \
  --publish 3022:22 \
  --publish 8080:80 \
  --publish 8443:443 \
  --volume /var/lib/dokku:/mnt/dokku \
  --volume /var/run/docker.sock:/var/run/docker.sock \
  dokku/dokku:latest

Dokku is run with the following options:
  • The global hostname is set to dokku.me on boot.
  • The container name is dokku.
  • Container SSH port 22 is exposed on the host as 3022.
  • Container HTTP port 80 is exposed on the host as 8080.
  • Container HTTPS port 443 is exposed on the host as 8443.
  • Data within the container is stored on the host within the /var/lib/dokku directory.
  • The docker socket is mounted into container

Application repositories, plugin config, and plugin data is persisted to disk within the specified host directory for /var/lib/dokku.
To install custom plugins, create a plugin-list file in the host's /var/lib/dokku directory. The plugins listed herein will be automatically installed by Dokku on container boot. This file should be the following format:
plugin_name: repository_url

An example for installing the postgres and redis plugins follows:
postgres: https://github.com/dokku/dokku-postgres.git
redis: https://github.com/dokku/dokku-redis.git

To initialize ssh-keys within the container, use docker exec to enter the container and run the appropriate ssh-keys commands.
docker exec -it dokku bash

Please see the user management documentation for more information.

Serve Dokku (container) on your own domain behind Caddy, Nginx or Traefik. Fill in your domain and copy the result. It's a starting point, some apps need their own base URL or extra headers set too.

Proxying dokku-container.example.com to http://dokku-container:80

Add this to your Caddyfile

dokku-container.example.com {
	reverse_proxy http://dokku-container:80
}

Check the logs first

Nine times out of ten the logs tell you exactly what went wrong.

  • In Portainer, go to Containers, click the container, then Logs. Or run docker logs <container>
  • Exit codes help too: 137 means killed, usually out of memory. 126 or 127 means the command inside the image is broken.

Published on a random port

This template exposes 22/tcp without setting a host port, so Docker picks a random free one on every deploy.

  • Find it in the Ports column of Portainer's container list, or with docker port <container>

Permission denied on volumes

If the logs show "permission denied", the app can't write to its data folder on the host.

  • Fix the ownership: sudo chown -R 1000:1000 /var/lib/dokku

Can't reach the Docker socket

This app talks to Docker through /var/run/docker.sock. If the logs show "permission denied while trying to connect to the Docker daemon socket", the app's user can't access it.

  • Check the socket exists on the host: ls -l /var/run/docker.sock
  • Run the container as root, or add the docker group's id to the container with group_add.

Image won't pull

Test the pull directly on the host: docker pull dokku/dokku

  • "manifest unknown" means the tag no longer exists. This template uses latest, so try pinning a specific version instead.
  • "toomanyrequests" is the Docker Hub rate limit. Log in with docker login to raise it.
  • "no space left on device" means a full disk. Reclaim space with docker system prune

"exec format error"

This means the image was built for a different CPU architecture than your server.

  • This image supports: amd64, arm64, arm/v7
  • Check yours with uname -m: x86_64 is amd64, aarch64 is arm64. Raspberry Pi and other ARM boards are the usual culprits.

Required settings are blank

DOKKU_HOSTNAME has no default value, and the app may crash or misbehave if left empty.

  • Fill it in on the deploy screen before hitting deploy.

Raise an issue

Found something which isn't working as it should? Here's how to report it.

A single container

Dokku (container) runs as one container, the simplest kind of app here. Just the one image to pull and nothing else wired up alongside it.

The app image

An image is the app packed up ready to go, everything Dokku (container) needs bundled into one download. This template pulls dokku/dokku, which Docker fetches once (about 568 MB) and then starts your own copy from.

Where the image comes from

Docker pulls its images from registries, public libraries of ready-built apps. Dokku (container)'s comes from Docker Hub, published by dokku.

Version tags

The bit after the colon in the image name is the version tag. Here it's latest, which always points at the newest build, so a redeploy can bump you to a newer release without you asking. Newest right now is 0.38.27. Pin a specific tag if you would rather stay on one version.

Which machines it runs on

Every image is built for particular CPU types. This one ships for amd64, arm64, arm/v7, so it runs on both regular x86 servers and ARM boards like a Raspberry Pi.

Ports

A port is the door the app answers on. Here the app exposes a port but leaves the host side blank, so Docker picks a free one for you. It opens:

  • 22, published on a random host port
  • 80, published on a random host port
  • 443, published on a random host port

Volumes

A volume is where Dokku (container) keeps its files so they survive an update or a restart. Without one, anything it saves would sit inside the container and vanish the moment it's recreated. This template mounts:

  • /mnt/dokku from /var/lib/dokku on the host
  • /var/run/docker.sock from /var/run/docker.sock on the host (a socket it talks to, not storage)

Environment variables

Environment variables are the settings you hand over when you deploy, things like a password or a timezone. Dokku (container) takes 2 of them, and one needs a value before it'll start properly:

  • DOKKU_HOSTNAME, needs a value. Global hostname to be registered by Dokku
  • DOKKU_HOST_ROOT, defaults to /var/lib/dokku/home/dokku. Image build cache path. Generally set to <data dir> + '/home/dokku'

Networking

Nothing custom is set, so Dokku (container) sits on Docker's default bridge network: its own private space that reaches the outside world only through the ports it publishes.

Platform

The platform is linux, the kind of system the container is built to run on. Docker and Portainer handle this on a normal Linux server.

Open source license

Dokku (container) is open source, released under the MIT license. In plain terms the code is out in the open, so you're free to run it and change it to fit what you need.

Portainer app templates

Zooming out, this whole page comes from a Portainer app template: a short recipe telling Portainer how to set Dokku (container) up. Add the template list to Portainer once, then deploying Dokku (container) is a click rather than a wall of config.