Reliability: It’s not great

What an earnest post, and how damn refreshing it is to see such concern for users, accountability, honesty and openness (quite a contrast to another PaaS)!

I moved one app successfully from heroku to fly and attempted to move a few others. These are my experiences (both good and bad):

Great:

- The load time on the pages is insanely faster on fly than heroku. Sometimes I thought I was on the localhost version of the app, it was that snappy.

- Love that it uses a Dockerfile

- Love paying for what I use (compared to Heroku's rigid minimum of $16/month for hobby dyno w/ postgres for baby apps, or $34/month just to get a second web dyno for toddler apps). The same apps are <$5/month each on fly.

Not great:

- I find the fly.toml file hard to understand and use, and the cycle time slow to fix or tinker with it. It's partly (entirely?) a 'me' problem because I haven't spent a huge amount of time reading the documentation.

- I found scheduling a rake task in a rails app time consuming (~days) the first time, but very easy (15 minutes) the second and subsequent times, once I knew a way that worked (cron didn't work; had to use a tool I hadn't used before 'supercronic').

- Deploys sometimes time out with `Error failed to fetch an image or build from source: error rendering push status stream: EOF`. Most layers copied, but randomly, some layers wouldn't. All I could do is keep trying until it worked, which it did, 2 hours later. Not the end of the world, but an annoying complication when you're already trying to solve complex problems.

- I followed a youtube video on how to move a rails app from heroku to fly, and it worked on a modern app, but I couldn't quite get fly happy when moving the older app - something to do with postgres versions, and I didn't want to spend all day figuring it out. I'm not hugely experienced with docker, it could have been an easy fix for someone more experienced.

On reflection, 3 of the 4 negatives above are solvable by me reading the docs more thoroughly and getting more proficient with docker.

I look forward to continuing using and exploring fly, and can't be happier with the directness, transparency and care from fly staff. A platform with huge potential.

Did you try migrating with this guide? https://fly.io/docs/rails/getting-started/migrate-from-herok...

The issues you ran into with older versions of Rails was probably because the Dockerfile that `fly launch` generated was for new versions of Rails. We switched to https://github.com/rubys/dockerfile-rails to streamline Dockerfile generation and support older versions of Rails.

If you try it again and run into issues you can open an issue at https://github.com/rubys/dockerfile-rails/issues or post in https://community.fly.io and somebody will help get that sorted out.

The more versions of Rails we can deploy the better!

You bet, that guide is gold.

I encountered a few issues. One was definitely something to do with older postgres. From memory, I tried downgrading it using apt, but then other things played up and I put the project aside.

Another rails 6 app I tried to move into fly encountered this: https://community.fly.io/t/rails-app-problem-with-node-modul...

I followed Sam's suggestions to regenerate the Dockerfile with dockerfile-rails (btw, thanks for your work on dockerfile-rails, super excited about it) and solved a couple more issues, but I again ran out of steam when new issues kept coming and coming. I'm sure when I'm more comfortable with docker these will become trivial to solve.

These were not super determined attempts by me, more playing around. I look forward to more serious attempts when I'm more capable with docker.