150 lines
6.3 KiB
Markdown
150 lines
6.3 KiB
Markdown
---
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title: Migrating to a new machine
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description: Copying your Mastodon installation to a new server without losing anything.
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menu:
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docs:
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weight: 90
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parent: admin
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---
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Sometimes, for various reasons, you may want to migrate your Mastodon instance from one server to another. Fortunately, this is not too difficult of a process, although it may result in some downtime.
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{{< hint style="info" >}}
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This guide was written with Ubuntu Server in mind; your mileage may vary for other setups.
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{{< /hint >}}
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## Basic steps {#basic-steps}
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1. Set up a new Mastodon server using the [Production Guide]({{< relref "install" >}}) (however, don’t run `mastodon:setup` and only leave the PostgreSQL service running).
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2. Stop Mastodon on the old server (e.g. `systemctl stop 'mastodon-*.service'`).
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3. Dump and load the PostgreSQL database using the instructions below.
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4. Copy the `system/` files using the instructions below. (Note: if you’re using S3, you can skip this step.)
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5. Copy the `.env.production` file.
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6. Save the Redis database, stop the Redis service, and copy the Redis database from `/var/lib/redis/` to the new server.
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7. Run `RAILS_ENV=production bundle exec rails assets:precompile` to compile Mastodon
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8. Start Mastodon and Redis on the new server.
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9. Run `RAILS_ENV=production ./bin/tootctl feeds build` to rebuild the home timelines for each user.
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10. Run `RAILS_ENV=production ./bin/tootctl search deploy` to rebuild your Elasticsearch indices (Note: if you are not using Elasticsearch, you can skip this step.)
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11. Update your DNS settings to point to the new server.
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12. Update or copy your Nginx configuration, and re-run LetsEncrypt as necessary.
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13. Enjoy your new server!
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## Detailed steps {#detailed-steps}
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### Stop the Mastodon services
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```bash
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systemctl stop 'mastodon-*.service'
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```
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### What data needs to be migrated {#what-data-needs-to-be-migrated}
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At a high level, you’ll need to copy over the following:
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* The `~/live/public/system` directory, which contains user-uploaded images and videos (if using S3, you don’t need this)
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* The PostgreSQL database (using [pg_dump](https://www.postgresql.org/docs/9.1/static/backup-dump.html))
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* The `~/live/.env.production` file, which contains server config and secrets
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* The Redis database in the `/var/lib/redis/` directory, which contains unproccessed Sidekiq jobs.
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Less crucially, you’ll probably also want to copy the following for convenience:
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* The nginx config (under `/etc/nginx/sites-available/mastodon`)
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* The SSL certificates for your domain (under `/etc/letsencrypt/live/` if using LetsEncrypt)
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* The systemd config files (`/etc/systemd/system/mastodon-*.service`), which may contain your server tweaks and customizations
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* The PgBouncer configuration under `/etc/pgbouncer` (if you’re using it)
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### Dump and load PostgreSQL {#dump-and-load-postgresql}
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Instead of running `mastodon:setup`, we’re going to create an empty PostgreSQL database using the `template0` database (which is useful when restoring a PostgreSQL dump, [as described in the pg_dump documentation](https://www.postgresql.org/docs/9.1/static/backup-dump.html#BACKUP-DUMP-RESTORE)).
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If you are using a password for your PostgreSQL user, you may want to configure the `mastodon` user on your new system to use the same password as your old system for convenience:
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```bash
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sudo -u postgres psql
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ALTER USER mastodon WITH PASSWORD 'YOUR_PASSWORD';
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\q
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```
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Run this as the `mastodon` user on your old system:
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```bash
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pg_dump -Fc mastodon_production -f backup.dump
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```
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Copy the `backup.dump` file over, using `rsync` or `scp`. Then on the new system, create an empty database as the `mastodon` user:
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```bash
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createdb -T template0 mastodon_production
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```
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Then import it (replace # in -j# with the number of CPUs in your system to improve restore performance):
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```bash
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pg_restore -Fc -j# -U mastodon -n public --no-owner --role=mastodon \
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-d mastodon_production backup.dump
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```
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(Note that if the username is not `mastodon` on the new server, you should change the `-U` AND `--role` values above. It’s okay if the username is different between the two servers.)
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### Copy files {#copy-files}
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This will probably take some time, and you’ll want to avoid re-copying unnecessarily, so using `rsync` is recommended. On your old machine, as the `mastodon` user, run:
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```bash
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rsync -avz ~/live/public/system/ mastodon@example.com:~/live/public/system/
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```
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You’ll want to re-run this if any of the files on the old server change.
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You should also copy over the `.env.production` file, which contains secrets.
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Now copy your Redis database over (adjust the location of your Redis database as needed). On your old machine, as the `root` user, run:
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```bash
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redis-cli
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SAVE
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EXIT
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systemctl stop redis-server.service
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rsync -avz /var/lib/redis/ root@example.com:/var/lib/redis
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```
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Optionally, you may copy over the nginx, systemd, and PgBouncer config files, or rewrite them from scratch.
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### During migration {#during-migration}
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You can edit the `~/live/public/500.html` page on the old machine if you want to show a nice error message to let existing users know that a migration is in progress.
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You’ll probably also want to set the DNS TTL to something small (30-60 minutes) about a day in advance, so that DNS can propagate quickly once you point it to the new IP address.
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### After migrating {#after-migrating}
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Run the following commands as your mastodon user:
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```bash
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RAILS_ENV=production bundle exec rails assets:precompile
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```
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Now run the following commands as your root user:
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```bash
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systemctl daemon-reload
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systemctl start redis-server
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systemctl enable --now mastodon-web mastodon-sidekiq mastodon-streaming
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systemctl restart nginx
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```
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Once your server is back online, you can rebuild the home feeds for users (this can take a long time depending on the number of users.)
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```bash
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RAILS_ENV=production ./bin/tootctl feeds build
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```
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If you use Elasticsearch, run the following command to rebuild the indices (this can take a long time depending on the number of statuses you have.)
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```bash
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RAILS_ENV=production ./bin/tootctl search deploy
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```
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You can check [whatsmydns.net](https://whatsmydns.net/) to see the progress of DNS propagation. To jumpstart the process, you can always edit your own `/etc/hosts` file to point to your new server so you can start playing around with it early.
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