Redis on Fly

The limited, "built-in" Redis caching that was previously known as Fly Redis is deprecated; we now recommend running Redis as a Fly.io app.

You can run a key/value store like Redis or KeyDB on Fly.io.

Here's a quick procedure to create a standalone Redis server as a Fly.io app in a single region, with persistent storage, and accessible only from apps within your organization.

Create the Fly.io app

We have a sweet Redis image you can use to create your own Redis instances on Fly.io. Use fly launch to create the new Redis app, but don't deploy yet:

fly launch --image flyio/redis:6.2.6 --no-deploy

When prompted, give the app a name (in this case my-fly-redis), and select a region. Let's use Chicago (ord) for this example.

The newly-generated fly.toml will specify the flyio/redis:6.2.6 image:

[build] 
 image = "flyio/redis:6.2.6"

Add persistent storage

We recommend adding a volume for persistent storage of Redis data. If you skip this step, data will be lost across deploys or restarts. The volume needs to be in the same region as the my-fly-redis app instance.

Here the volume is called redis_server and we use fly volumes create to put it in ord where the app is configured to deploy.

fly volumes create redis_server --region ord

       ID: vol_6d7xkrk7do64w2q9 
     Name: redis_server 
   Region: ord
      Zone: 2c30 
  Size GB: 10 
 Encrypted: true 
Created at: 03 Dec 21 21:47 UTC

Tweak fly.toml

When we ran fly launch, it generated a fly.toml configuration file. We need to make some adjustments to it.

Attach the storage volume

The following [[mounts]] section tells the new Redis app to mount the redis_server volume at /data when it starts.

[[mounts]]
  destination = "/data"
  source = "redis_server"

Hook up metrics

Add metrics:

[metrics]
  port = 9091
  path = "/metrics"

Services

A default [[services]] section was generated on fly launch for internal port 8080. Redis doesn't use port 8080; additionally, it's unlikely that you want your public Redis exposed on the public internet.

So delete the [[services]] section.

Other apps within the same organization can still access the Redis server over the Fly.io private network, at my-fly-redis.internal:6379, but will not be mapped to the external internet.

Add a password for Redis

This installation requires setting a password on Redis before deploying.

fly secrets set REDIS_PASSWORD=MY_REDIS_PW

Keep track of this password - it won't be visible again after deployment! More on fly secrets here.

Deploy

fly deploy

If all goes well (check with fly status), the new Redis server app my-fly-redis will now accept connections from your organization's other apps on the private IPv6 network, on the standard port 6379.

Test the Redis server

You can test the app with fly ssh console. Your Fly.io organization must have a root SSH certificate established in order to do this; check using fly ssh log.

Connect to my-fly-redis:

fly ssh console -a my-fly-redis

Connecting to top1.nearest.of.my-fly-redis.internal... complete
/ # redis-cli

Once in the redis-cli, authenticate. At that point you can run Redis commands interactively on the server.

127.0.0.1:6379> auth MY_REDIS_PW
OK
127.0.0.1:6379> ping
PONG