Upgrading from Dokku to Flynn

One of the most common ways developers find Flynn is when they’re looking for an alternative to Dokku.

Dokku is a widely used open source mini PaaS. It’s a great introduction to what platforms can offer and easy to get up and running on a single server. It’s also tiny and a model of efficiency, originally written in just 100 lines of Bash.

Many developers choose Dokku because it provides many of the benefits of PaaS, but can be run anywhere on a single server.

Unfortunately the feature that makes Dokku so attractive to developers working on personal side projects, its single host nature, makes it unsuitable for larger and production deployments.

Running as a single instance on a single server prohibits high availability. A single host means there’s a single point of failure. If that server goes down, everything breaks. It also means that users need to do a lot of heavy lifting themselves to scale out.

Flynn includes all the benefits of Dokku without its limitations. One of Flynn’s original design goals was to be the next step on the upgrade path for Dokku users. Both Flynn and Dokku were created to give users the benefits of Heroku, but with more control and the ability to run anywhere they wanted.

Like Dokku, Flynn is also easy to use and install, but scalable, far more robust, and suited to production environments. Everything in Flynn is highly available, so there’s no single point of failure. Even Flynn’s internal components run inside the cluster as highly available Flynn apps.

You can run Flynn on a single server or scale it out to many, many more. Flynn has a web dashboard that makes it even easier to use. Flynn also includes built-in database appliances, which you can think of like having a database as a service (DbaaS) inside your Flynn cluster. Other features you’ll need for scaling production apps like overlay networking and service discovery are also built-in.

If you’re already running your apps on Dokku, it’s very easy to migrate to Flynn. Here’s how:

  1. Install Flynn.
  2. Deploy your apps using git push or Docker images.

It’s that simple.

Since both Flynn and Dokku support Twelve-Factor apps and buildpacks, any Dokku app can run on Flynn.

If you want an alternative to Dokku or just the next step after you’ve outgrown it, Flynn is what you’re looking for.

Our team is available on GitHub, in IRC, and over email if you want help moving your apps or have any questions.


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