fly-io-config

LiteFS Example Application on Fly.io

Prerequisites

First, you'll need to install flyctl and then sign up for a free account.

Usage

Creating the application

First, we'll need to create our application on Fly.io. This will prompt you for a name or you can autogenerate one for this example. Remember this name as we'll need it later.

fly launch --region ord --no-deploy

The launch command will create a fly.toml file and set the primary region to Chicago (ord) but will not launch the app.

Creating a volume

Next, we need to set up a persistent volume in our primary region so that our data is not lost between restarts.

fly volumes create -r ord --size 1 litefs

And add a mount to this volume in your fly.toml file:

[mounts]
  source = "litefs"
  destination = "/var/lib/litefs"

Setting up Consul

LiteFS uses Consul for its distributed lease. You can find instructions for using Fly.io's free multi-tenant Consul in the Lease Management section of the Getting Started guide.

Launching your app

The next step is to launch & deploy your app with the following command:

fly deploy

The application should build and deploy and you should see it up in running after a minute or so. You can go to https://$APPNAME.fly.dev/ and see your application running live.

The application is a simple interface for generating fake records. It's just for illustrating how LiteFS can easily replicate your data between nodes.

When you click the "Generate Record" button, it will create that row in a local SQLite database that is running on a LiteFS file system. Any other node running LiteFS will automatically get those updates and apply them to their local copy of the database. That lets every node keep an exact copy of the same database.

Launching more regions

This example application is configured to run as a primary only in the PRIMARY_REGION (which is Chicago). It's best practice to run two or more instances in the primary region and then you can add instances in additional regions to reduce latency for your users.

You can clone the configuration of the machine to other regions by using the fly m clone command. The --select flag lets you choose from a list of existing machines to clone.

# Make a second instance in your primary region.
fly m clone --select --region ord

# Make additional instances in regions around the world (London, Sydney, etc).
fly m clone --select --region lhr
fly m clone --select --region syd