How to Use the Command 'dokku' (with examples)

Dokku is a powerful tool that allows you to set up your own Platform as a Service (PaaS) using Docker. It simplifies the deployment of multiple applications on your server with just a single git-push command. Dokku is especially useful for developers who want to manage their applications on their infrastructure without relying on third-party PaaS services. With Dokku, you can create, manage, and remove applications, install plugins, and link databases to applications seamlessly.

List Running Apps (with examples)

Code:

dokku apps

Motivation:

Listing running applications is crucial for server administrators and developers alike to understand what services are currently active on the server. This helps in monitoring and managing resources effectively, ensuring that the server is not overloaded and all deployed applications are running as expected.

Explanation:

In this command, dokku is the tool being used, and apps is the sub-command that retrieves the list of applications currently deployed and running on your Dokku-managed server. There are no additional arguments needed since the goal is simply to produce a list.

Example Output:

=====> My Dokku Managed Applications
app1
app2
app3

Create an App (with examples)

Code:

dokku apps:create app_name

Motivation:

Creating an application is the first step in deploying a new service on your server. Whether you are starting a new project or deploying an existing one, setting up an application space is necessary for further configuration and deployment.

Explanation:

The dokku tool is again invoked, with the apps:create sub-command specifying that a new application should be created. The app_name argument is a placeholder for the name you wish to assign to the new application. This name should be unique within the Dokku environment and is used for further operations like deployment and management.

Example Output:

=====> Creating app app_name...
       App app_name created

Remove an App (with examples)

Code:

dokku apps:destroy app_name

Motivation:

There are times when an application is no longer needed, whether because it is deprecated, replaced, or simply due to a change in project requirements. Removing an unused application helps free up server resources and maintain a clean, organized environment.

Explanation:

The command utilizes dokku with the apps:destroy sub-command, indicating the intention to delete an application. The app_name argument represents the name of the application you wish to remove. This operation will typically prompt a confirmation to prevent accidental deletions.

Example Output:

 !     Warning, potentially destructive action
 !     This command will destroy app_name (including all add-ons)
 !     To proceed, type "app_name" or re-run this command with --force
>
=====> Deleting app_name...
       App app_name destroyed

Install Plugin (with examples)

Code:

dokku plugin:install full_repo_url

Motivation:

Plugins extend Dokku’s functionality, allowing you to add new features and integrations. Installing plugins can be necessary for enabling support for additional languages, databases, or other services that are not included by default in Dokku.

Explanation:

In this command, dokku is used alongside plugin:install, a sub-command that manages plugin installation. The full_repo_url argument is the URL to the Git repository of the plugin you want to install. This command fetches the plugin from the specified repository and installs it onto your Dokku instance.

Example Output:

-----> Plugin (https://github.com/example/dokku-plugin.git) installed
       Please restart dokku to enable plugin functionality

Link Database to an App (with examples)

Code:

dokku db:link db_name app_name

Motivation:

Linking a database to an application is a frequent requirement, as most applications rely on some form of persistent storage to function correctly. This command facilitates the seamless integration of your application with a database service managed by Dokku.

Explanation:

Here, dokku is followed by the db:link sub-command, which manages database connections. The db_name argument specifies the name of the database you intend to link, while app_name designates the application that requires access to the database. This command ensures that the application can connect to and use the specified database.

Example Output:

=====> Linking db_name to app_name
       Successfully linked database to application

Conclusion:

Dokku is a versatile and efficient tool designed for developers who want more control over their deployment environments. By using simple commands, you can manage applications, integrate databases, and expand functionality with plugins. Whether you’re just starting with Dokku or looking to optimize your current setup, understanding these command use cases can significantly enhance your deployment workflow.