ITSquad/Mastodon/Maintenance

This page aims to describe procedures to maintain the Pirate Party's Mastodon instance.

How to upgrade?

A script called update.sh located in /home/mastodon will reproduce the steps below. Note: this script stops at step 14 and does not go further.

Before running this script or the following commands, please check the instruction for the current release. Sometimes, aditionnal actions are needed (other than migrate database and compile assets)

1. git fetch # update the git branch
2. git stash # prevent changes made to the files to be overwritten (mainly, the docker-compose.yml file)
3. git checkout vX.X.X # jump to the version where we want to update
4. git stash pop # restore your changes
5. docker-compose pull # pull from the docker-hub https://hub.docker.com/r/gargron/mastodon/
6. docker-compose stop # stop the containers
7. docker-compose start db # start the db container
8. docker-compose exec db pg_dump -U postgres -Fc postgres > ../dump_$(date +%d-%m-%Y"_"%H_%M_%S).sql # backup the database
9. tail ../your_dump_file.sql # check if the backup worked, with your_dump_file.sql being the dumpfile you have created in the previous step.
10. docker-compose down # shut down the containers.

    # You'll maybe get "ERROR: An HTTP request took too long to complete" and other errors. Don't mind this and just wait 'till it's done.

11. docker-compose run --rm web rails db:migrate # upgrade the database
12. docker-compose run --rm web rails assets:precompile # complie the assets
13. docker-compose up -d # start the mastodon instance (create new volumes)
14. docker-compose logs -ft web # (optional) if you want to monitor the progress. Once this is done you ctrl+c
15. docker volume prune # remove all unused volumes

What to do when something went wrong?

Don't panic. You can restore the database backup as follows:

1. docker-compose stop
2. docker-compose start db
3. docker-compose exec db dropdb postgres -U postgres # remove the db !!!!!!!
4. docker-compose exec db createdb postgres -U postgres # create a fresh and new db
5. cat ../your_dump_file.sql | docker exec -i mastodon_db_1 psql -U postgres # restore the database, with "your_dump_file" being a database backup
6. docker-compose down
7. docker-compose up -d

You can also go to a previous version of Mastodon with:

1. git checkout vX.X.X
2. sed s/:latest/:vX.X.X/g docker-compose.yml # don't forget to change this back to "latest" when things get fixed
3. docker-compose pull

How to backup?

Backups of the database are not enough. We need to backup images, user feeds, etc.

We can simply copy the whole Mastodon's directory. For instance:

tar cvf /home/mastodon/backup/mastodon.tar /home/mastodon/mastodon/

Then, we backup the database:

docker-compose exec db pg_dump -U postgres -Fc postgres > /home/mastodon/backup/db/dump_`date +%d-%m-%Y"_"%H_%M_%S`.sql

It can be interesting to execute the following command before doing a backup:

NUM_DAYS=14 docker-compose run --rm web rails mastodon:media:remove_remote

This will remove local cache of media older than NUM_DAYS (=7 by default, but here we set at 14 days). Note that this command is executed every day on our instance.

Currently, HgO is doing a daily backup (db + media), and keep them up to 7 days. Data are stored on his laptop.

Every night, a backup of the db is also made on the server (but is overwritten by the nightly backup).

We still need to implement a more reliable solution