New as of 0.5.0
The preferred method to mount external containers to a Dokku managed container, is to use the Dokku storage plugin.
storage:list <app> # List bind mounts for app's container(s) (host:container) storage:mount <app> <host-dir:container-dir> # Create a new bind mount storage:report [<app>] [<flag>] # Displays a checks report for one or more apps storage:unmount <app> <host-dir:container-dir> # Remove an existing bind mount
The storage plugin is compatible with storage mounts created with the docker-options. The storage plugin will only list mounts from the deploy/run phase.
The storage plugin supports the following mount points:
There are a few caveats to using the persistent storage plugin:
/var/lib/dokku/data/storagedirectory as the root host path for mounts, and we create this on Dokku installation.
/- and are not relative to
/app(for buildpacks deploys) or the
WORKDIR(for Dockerfile/Docker images).
32767. This is due to how permissions within Herokuish - which builds the Docker images - works. For Dockerfile or Docker image deployments, please use the user and group id which corresponds to the one running the process within the container.
This example demonstrates how to mount the recommended directory to
/storage inside an application called
# we use a subdirectory inside of the host directory to scope it to just the app dokku storage:mount node-js-app /var/lib/dokku/data/storage/node-js-app:/storage
Dokku will then mount the shared contents of
/storage inside the container.
Once you have mounted persistent storage, you will also need to restart the application. See the process scaling documentation for more information.
dokku ps:restart app-name
A more complete workflow may require making a custom directory for your application and mounting it within your
/app/storage directory instead. The mount point is not relative to your application's working directory, and is instead relative to the root of the container.
# creating storage for the app 'node-js-app' mkdir -p /var/lib/dokku/data/storage/node-js-app # ensure the proper user has access to this directory chown -R dokku:dokku /var/lib/dokku/data/storage/node-js-app # as of 0.7.x, you should chown using the `32767` user and group id for buildpack deploys # For dockerfile deploys, substitute the user and group id in use within the image chown -R 32767:32767 /var/lib/dokku/data/storage/node-js-app # mount the directory into your container's /app/storage directory, relative to root dokku storage:mount app-name /var/lib/dokku/data/storage/node-js-app:/app/storage
You can mount one or more directories as desired by following the above pattern.
New as of 0.8.1
You can get a report about the app's storage status using the
=====> node-js-app storage information Storage build mounts: Storage deploy mounts: -v /var/lib/dokku/data/storage/node-js-app:/app/storage Storage run mounts: -v /var/lib/dokku/data/storage/node-js-app:/app/storage =====> python-sample storage information Storage build mounts: Storage deploy mounts: Storage run mounts: =====> ruby-sample storage information Storage build mounts: Storage deploy mounts: Storage run mounts:
You can run the command for a specific app also.
dokku storage:report node-js-app
=====> node-js-app storage information Storage build mounts: Storage deploy mounts: -v /var/lib/dokku/data/storage/node-js-app:/app/storage Storage run mounts: -v /var/lib/dokku/data/storage/node-js-app:/app/storage
You can pass flags which will output only the value of the specific information you want. For example:
dokku storage:report node-js-app --storage-deploy-mounts
Dokku is powered by Docker containers, which recommends in their best practices that containers be treated as ephemeral. In order to manage persistent storage for web applications, like user uploads or large binary assets like images, a directory outside the container should be mounted.
When scaling your app, you may require a common location to access shared assets between containers, a storage mount can be used in this situation.
Your app may be used in a cluster that requires containers or resources not running on the same host access your data. Mounting a shared file service (like S3FS or EFS) inside your container will give you great flexibility.
Your app may have services that are running in memory and need to be backed up locally (like a key store). Mount a non ephemeral storage mount will allow backups that are not lost when the app is shut down.
By default, Dokku will only bind storage mounts during the deploy and run phases. Under certain conditions, one might want to bind a storage mount during the build phase. This can be accomplished by using the
docker-options plugin directly.
dokku docker-options:add node-js-app build "-v /tmp/python-test:/opt/test"
You cannot use mounted volumes during the build phase of a Dockerfile deploy. This is because Docker does not support volumes when executing
Note: This can cause data loss if you bind a mount under
/appin buildpack apps as herokuish will attempt to remove the original app path during the build phase.
New as of 0.7.1
By default, Dokku will execute your buildpack application processes as the
herokuishuser user. You may override this by setting the
DOKKU_APP_USER config variable.
NOTE: this user must exist in your herokuish image.
Additionally, the default
docker-local scheduler that comes with Dokku will ensure your storage mounts are owned by either
herokuishuser or the overridden value you have set in
DOKKU_APP_USER. See the docker-local scheduler documentation docs for more information.