Deploying an Application¶
This walkthrough uses the hostname
dokku.me in commands. When deploying to your own server, you should substitute the domain
dokku.me for the domain name or IP address associated with your server. Users of the Vagrant VM included with Dokku can use
dokku.me which points to the IP of the VM.
Once you have configured Dokku with at least one user, you can deploy applications using
git push. To quickly see Dokku deployment in action, try using the Heroku Ruby on Rails "Getting Started" app.
Create the app¶
SSH into the Dokku host and create the application as follows:
Create the backing services¶
Dokku by default does not provide datastores (e.g. MySQL, PostgreSQL) on a newly created app. You can add datastore support by installing plugins, and the Dokku project provides official plugins for common datastores.
The Getting Started app requires a PostgreSQL service, so install the plugin and create the related service as follows:
Each service may take a few moments to create.
Linking backing services to applications¶
Once the services have been created, you then set the
DATABASE_URL environment variable by linking the service, as follows:
Dokku supports linking a single service to multiple applications as well as linking only one service per application.
Deploy the app¶
Your app should respect the
PORT environment variable, otherwise it may not respond to web requests. You can find more information in the port management documentation.**
Now you can deploy the
ruby-getting-started app to your Dokku server. All you have to do is add a remote to name the app. Applications are created on-the-fly on the Dokku server.
Some tools may not support the short-upstream syntax referenced above, and you may need to prefix
the upstream with the scheme
ssh:// like so:
Please see the Git documentation for more details.
Your private key should be registered with
ssh-agent in your local development environment. If you get a
permission denied error when pushing, you can register your private key as follows:
ssh-add -k ~/<your private key>.
git push dokku main, you should have output similar to this in your terminal:
Counting objects: 231, done. Delta compression using up to 8 threads. Compressing objects: 100% (162/162), done. Writing objects: 100% (231/231), 36.96 KiB | 0 bytes/s, done. Total 231 (delta 93), reused 147 (delta 53) -----> Cleaning up... -----> Building ruby-getting-started from herokuish... -----> Adding BUILD_ENV to build environment... -----> Ruby app detected -----> Compiling Ruby/Rails -----> Using Ruby version: ruby-2.2.1 -----> Installing dependencies using 1.9.7 Running: bundle install --without development:test --path vendor/bundle --binstubs vendor/bundle/bin -j4 --deployment Fetching gem metadata from https://rubygems.org/........... Fetching version metadata from https://rubygems.org/... Fetching dependency metadata from https://rubygems.org/.. Using rake 10.4.2 ... =====> Application deployed: http://ruby-getting-started.dokku.me
Once the deploy is complete, the application's web URL will be generated as above.
Dokku supports deploying applications in a few ways:
- Heroku buildpacks via Herokuish: See the herokuish buildpacks documentation to learn about the different ways to specify a buildpack.
- This is the default method used by Dokku.
- Dockerfile: See the dockerfile documentation to learn about the different ways to configure Dockerfile-based deploys.
- Docker Image: See the docker image documentation to learn about how to deploy a Docker Image.
Setting up SSL¶
While SSL certificates can be imported, automated SSL via Letsencrypt requires that all domains on an app correctly point at your server's public ip address. Please keep this in mind when using Letsencrypt.
For many users, responding to requests via
https will be desirable. Dokku has a complete ssl plugin built in that can be used to import SSL certificates (below is a short example, please refer to the ssl documentation for more information):
As an alternative, the Dokku project offers an optional letsencrypt plugin that can be used to automate SSL certificate retrieval and renewal.
# on the Dokku host # install the letsencrypt plugin # plugin installation requires root, hence the user change sudo dokku plugin:install https://github.com/dokku/dokku-letsencrypt.git # set global email for letsencrypt dokku letsencrypt:set --global email email@example.com # set a custom domain that you own for your application dokku domains:set ruby-getting-started ruby-getting-started.your.domain.com # enable letsencrypt dokku letsencrypt:enable ruby-getting-started # enable auto-renewal dokku letsencrypt:cron-job --add
If you only want to rebuild and tag a container, you can skip the deployment phase by setting
true by running:
Redeploying or restarting¶
If you need to redeploy or restart your app:
See the process scaling documentation for more information on how to manage your app processes.
Deploying with private Git submodules¶
Dokku uses Git locally (i.e. not a Docker image) to build its own copy of your app repo, including submodules, as the
dokku user. This means that in order to deploy private Git submodules, you need to put your deploy key in
/home/dokku/.ssh/ and potentially add
github.com (or your VCS host key) into
/home/dokku/.ssh/known_hosts. You can use the following test to confirm your setup is correct:
if the buildpack or Dockerfile build process require SSH key access for other reasons, the above may not always apply.
Deploying to subdomains¶
If you do not enter a fully qualified domain name when pushing your app, Dokku deploys the app to
<remotename>.yourdomain.tld as follows:
You can also specify the fully qualified name as follows:
This is useful when you want to deploy to the root domain:
Dokku/Docker container management compatibility¶
Dokku is, at its core, a Docker container manager. Thus, it does not necessarily play well with other out-of-band processes interacting with the Docker daemon.
Prior to every deployment, Dokku will execute a cleanup function. As of 0.5.x, the cleanup removes all containers with the
dokku label where the status is either
exited (previous versions would remove all
exited containers). The cleanup function also removes all images with
Adding deploy users¶
See the user management documentation for more information on how to manage users with access to your Dokku server.
See the domains documentation for more information on how to manage the default site.
Deploying non-master branch¶
See the Git documentation for more information on deploying a non-master branch to your application.
See the Dockerfile documentation for information Dokku's Dockerfile support.
See the image tagging documentation for more information on how Docker images can be tagged and deployed for a given application.
Specifying a custom buildpack¶
See the herokuish buildpack documentation for more information on how to specify a set of custom buildpacks for your application.
Removing a deployed app¶
See the application management documentation for more information on how to remove an application from your Dokku server.
Renaming a deployed app¶
See the application management documentation for more information on how an application can be renamed and the impact of doing so upon the application and associated resources.
Zero downtime deploy¶
See the zero-downtime deploy documentation for more information on how Dokku enables zero-downtime deploys.