Migrating a mediawiki instance from one dokku server to another

On the old server

dokku mysql:export wiki_db > wiki_db.dump
tar -cvf storage.tar.gz /var/lib/dokku/data/storage

On local machine

Download the dump

sftp user@oldvps
get wiki_db.dump
get storage.tar.gz

Then exit sftp and copy the dump to the new server

scp wiki_db.dump vps:/home/user/
scp storage.tar.gz vps:/home/user/

Dokku on the new server

dokku apps:create wiki
tar xfv storage.tar.gz
sudo cp -r storage/wiki /var/lib/dokku/data/storage/wiki

dokku storage:ensure-directory wiki

dokku storage:mount wiki /var/lib/dokku/data/storage/wiki/extensions:/var/www/html/extensions

dokku storage:mount wiki /var/lib/dokku/data/storage/wiki/images:/var/www/html/images

dokku storage:mount wiki /var/lib/dokku/data/storage/wiki/LocalSettings.php:/var/www/html/LocalSettings.php 

dokku storage:mount wiki /var/lib/dokku/data/storage/wiki/skins:/var/www/html/skins

dokku mysql:create wiki_db
dokku mysql:link wiki_db wiki
dokku mysql:import wiki_db < wiki_db.dump

Look at what the DATABASE_URL has been set to and get the db pass from there.

Modify the LocalSettings.php to use the new password

## The protocol and server name to use in fully-qualified URLs  
$wgServer = "https://wiki.example.com";

## Database settings
$wgDBtype = "mysql";
$wgDBserver = "dokku-mysql-wiki-db:3306";
$wgDBname = "wiki_db";
$wgDBuser = "mysql";
$wgDBpassword = "supersecretstring";

While you're at it, check the LocalSettings.php for any skins that might loaded but not installed.

dokku git:from-image wiki mediawiki:stable
dokku letsencrypt:enable wiki

Then manually upgrade:

dokku enter wiki web
# mediawiki
php maintenance/run.php update.php

Then rebuild:

dokku ps:rebuild wiki

Troubleshooting

If there's an error about the skins when you go to the wiki, you might have to unmount the skins folder and copy it from the container.

dokku storage:unmount wiki /var/lib/dokku/data/storage/wiki/skins:/var/www/html/skins
dokku ps:rebuild wiki

Get the container id from sudo docker ps. Then copy the skins folder from container to host.

sudo docker cp 6aa2d9e79a12:/var/www/html/skins skins
cd /var/lib/dokku/data/storage/wiki
sudo mv skins oldskins
sudo cp ~/skins .
dokku storage:ensure-directory wiki
dokku storage:mount wiki /var/lib/dokku/data/storage/wiki/skins:/var/www/html/s  
kins
dokku ps:rebuild wiki