In 2016 I moved half a dozen apps from Heroku to a DigitalOcean droplet to save money. I found dokku, a docker-powered PaaS. It was already quite mature, and worked flawlessly. In 2023 I am moving back from the single droplet to apps, but staying on DigitalOcean. It was a good 7-year-long run for my droplet!
What am I moving?
I’ve got 4 profitable, and 5 money-losing or free Slack apps, all open-source.
- www.playplay.io: A ping-pong/chess/pool/tic-tac-toe leaderboard for Slack.
- slava.playplay.io: Strava integration in Slack.
- sup.playplay.io: Helps team members meet every week in an informal standup.
- market.playplay.io: Stock market quotes in Slack.
- moji.playplay.io: More emoji in Slack.
- invite.playplay.io: Help your users join your Slack.
- arena.playplay.io: Are.na integration with Slack.
- shell.playplay.io: Whoa, a bash shell inside Slack!
- api-explorer.playplay.io: A Slack web API explorer.
Over the years I got increasingly nervous about doing any kind of maintenance operations on the Linux droplet. Upgrading Dokku, or its plugins, under half a dozen applications had the potential side effect of taking all my projects down at once. Before doing anything drastic, I would cautiously snapshot my droplet. For major upgrades, I would even power the droplet down before making a snapshot, incurring half an hour of downtime. Then I’d type
sudo apt-get upgrade, fingers crossed. A couple of times these operations would render the host inoperable, so I’d revert and figure out a manual path forward.
In early 2022 the inevitable happened: I got permanently stuck with an old Linux distro that just would not upgrade the ancient 3.13 kernel to 4.x. Slack runs periodic pentests on its marketplace bots, and I was now running on non-LTS versions of Ruby, whereas newer versions would not work on the old kernel (securerandom.rb:75:in ‘urandom’: failed to get urandom (RuntimeError)). I was forced to upgrade, but every attempt to bring my Dokku apps back up on a 4.x kernel failed. Docker refused to start with my existing data.
I finally had to accept that I was just not smart enough to understand what “aufs is not supported anymore” meant, or how I was supposed to “use overlay” without losing all my existing data, despite the fact that “as far as people know, only ephemeral container data is stored in that aufs path”. I was that old to understand how Docker worked. I’ve finally reached the level of my incompetence!
The only workable solution was to provision a new server with a newer Linux distro, and migrate everything to it. Instead, I decided to evaluate other options. Because DigitalOcean had been a reliable and trusted platform for 7 years, I went with DigitalOcean apps.
Here’s a migration cookbook, mostly for my own reference.
Lower the DNS TTL to a minute about an hour prior to migration.
- Stop the dokku container on the droplet with
dokku ps:stop app.
- Lock the app to prevent future accidental deployments with
dokku apps:lock app.
- Export data from MongoDB with
dokku mongo:export app > app.dump.gz.
- Fetch the data from the droplet and back it up with
scp root@domain:/path/to/data/app.dump.gz ..
- Restore data into the new managed MongoDB database.
Create an App
- Set the new name to
- Choose a GitHub repository for source code, grant permissions as needed.
Edit Plan, reduce containers to 1, choose a $5 basic or $12/pro plan.
Add Resource, and add a previously created MongoDB database, which adds a user with proper authorizations.
- Edit environment settings. Copy them from
dokku config appon the droplet. Remove
DATABASE_URLthat was added automatically, since it doesn’t include the right database name.
- Set the MongoDB database URL
- Change a default app name to
- Deploy the app.
Add a domain in app settings, update the DNS entry, re-increase back the DNS record TTL.
My monthly server total was $134.39 ($96 for a s-8vcpu-16gb droplet, $4.89 for droplet snapshots, $19.20 for droplet backups, $10.00 for an external 100GB volume for MongoDB data, and $4.30 for volume snapshots).
Monthly app cost is $103 (5x$5 for basic apps, 4x$12 for pro, $30.00 for a shared 1gb-1vcpu-15gb MongoDB).
It’s actually cheaper to use apps than the droplet for roughly the same capacity and availability, minus having to manage infrastructure.
I think DigitalOcean apps are priced very well for my use-case. If you’ve never used the platform, sign up for an account using my referral link, and thank you.