Updated the migrating.md document (#1390)

* Updated the migrating.md document
Included new guidance to update the mastodon database user password, instructions to copy over the Redis database, added new flag to improve pg_restore performance, a suggestion to copy the SSL certificates over, and added the commands needed to complete the migration along with an optional command for Elasticsearch.
* Update content/en/admin/migrating.md
* Update migrating.md
Fixed wording and order of starting services.
* Updated the migration guide for Redis and services
Added more details for migrating the Redis database and where/when to stop the services.

Co-authored-by: Michael Stanclift <mx@vmstan.com>

content/en/admin/migrating.md

@@ -15,20 +15,28 @@ This guide was written with Ubuntu Server in mind; your mileage may vary for oth
 
 ## Basic steps {#basic-steps}
 
-1. Set up a new Mastodon server using the [Production Guide]({{< relref "install" >}}) (however, don’t run `mastodon:setup`).
+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).
 2. Stop Mastodon on the old server (e.g. `systemctl stop 'mastodon-*.service'`).
 3. Dump and load the PostgreSQL database using the instructions below.
 4. Copy the `system/` files using the instructions below. (Note: if you’re using S3, you can skip this step.)
 5. Copy the `.env.production` file.
-6. Run `RAILS_ENV=production bundle exec rails assets:precompile` to compile Mastodon
-7. Run `RAILS_ENV=production ./bin/tootctl feeds build` to rebuild the home timelines for each user.
-8. Start Mastodon on the new server.
-9. Update your DNS settings to point to the new server.
-10. Update or copy your Nginx configuration, and re-run LetsEncrypt as necessary.
-11. Enjoy your new server!
+6. Save the Redis database, stop the Redis service, and copy the Redis database from `/var/lib/redis/` to the new server.
+7. Run `RAILS_ENV=production bundle exec rails assets:precompile` to compile Mastodon
+8. Start Mastodon and Redis on the new server.
+9. Run `RAILS_ENV=production ./bin/tootctl feeds build` to rebuild the home timelines for each user.
+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.)
+11. Update your DNS settings to point to the new server.
+12. Update or copy your Nginx configuration, and re-run LetsEncrypt as necessary.
+13. Enjoy your new server!
 
 ## Detailed steps {#detailed-steps}
 
+### Stop the Mastodon services  
+
+```bash
+systemctl stop 'mastodon-*.service'
+```
+
 ### What data needs to be migrated {#what-data-needs-to-be-migrated}
 
 At a high level, you’ll need to copy over the following:
@@ -36,16 +44,26 @@ At a high level, you’ll need to copy over the following:
 * The `~/live/public/system` directory, which contains user-uploaded images and videos (if using S3, you don’t need this)
 * The PostgreSQL database (using [pg_dump](https://www.postgresql.org/docs/9.1/static/backup-dump.html))
 * The `~/live/.env.production` file, which contains server config and secrets
+* The Redis database in the `/var/lib/redis/` directory, which contains unproccessed Sidekiq jobs.
 
 Less crucially, you’ll probably also want to copy the following for convenience:
 
 * The nginx config (under `/etc/nginx/sites-available/mastodon`)
+* The SSL certificates for your domain (under `/etc/letsencrypt/live/` if using LetsEncrypt)
 * The systemd config files (`/etc/systemd/system/mastodon-*.service`), which may contain your server tweaks and customizations
 * The PgBouncer configuration under `/etc/pgbouncer` (if you’re using it)
 
 ### Dump and load PostgreSQL {#dump-and-load-postgresql}
 
-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)).
+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)).  
+
+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:
+
+```bash
+sudo -u postgres psql  
+ALTER USER mastodon WITH PASSWORD 'YOUR_PASSWORD';  
+\q
+```
 
 Run this as the `mastodon` user on your old system:
 
@@ -59,10 +77,10 @@ Copy the `backup.dump` file over, using `rsync` or `scp`. Then on the new system
 createdb -T template0 mastodon_production
 ```
 
-Then import it:
+Then import it (replace # in -j# with the number of CPUs in your system to improve restore performance):
 
 ```bash
-pg_restore -Fc -U mastodon -n public --no-owner --role=mastodon \
+pg_restore -Fc -j# -U mastodon -n public --no-owner --role=mastodon \
   -d mastodon_production backup.dump
 ```
 
@@ -76,10 +94,20 @@ This will probably take some time, and you’ll want to avoid re-copying unneces
 rsync -avz ~/live/public/system/ mastodon@example.com:~/live/public/system/
 ```
 
-You’ll want to re-run this if any of the files on the old server change.
+You’ll want to re-run this if any of the files on the old server change.  
 
 You should also copy over the `.env.production` file, which contains secrets.
 
+Now copy your Redis database over (adjust the location of your Redis database as needed). On your old machine, as the `root` user, run:
+
+```bash
+redis-cli
+SAVE
+EXIT
+systemctl stop redis-server.service
+rsync -avz /var/lib/redis/ root@example.com:/var/lib/redis
+```
+
 Optionally, you may copy over the nginx, systemd, and PgBouncer config files, or rewrite them from scratch.
 
 ### During migration {#during-migration}
@@ -90,5 +118,32 @@ You’ll probably also want to set the DNS TTL to something small (30-60 minutes
 
 ### After migrating {#after-migrating}
 
+Run the following commands as your mastodon user:  
+
+```bash
+RAILS_ENV=production bundle exec rails assets:precompile  
+```
+
+Now run the following commands as your root user:
+
+```bash
+systemctl daemon-reload
+systemctl start redis-server  
+systemctl enable --now mastodon-web mastodon-sidekiq mastodon-streaming  
+systemctl restart nginx
+```
+
+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.)
+
+```bash
+RAILS_ENV=production ./bin/tootctl feeds build
+```
+
+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.)
+
+```bash
+RAILS_ENV=production ./bin/tootctl search deploy
+```
+
 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.