Backup & Restore WordPress: bash + Docker

To back up a WordPress website, you need to backup two components:

• database: posts, pages, categories, comments, users, plugin data, etc.
• filesystem: media, plugins, files, etc.

Here we see how to backup and restore a WordPress instance via command line both in pure-bash fashion and also wordpress is running on docker.

Backup/Restore via bash

First, create a config file to source for variables. Remember this file must stay private.

WP_DATA_DIR=/var/www/html/wp-content

# provide DB name, user and pass
DB_NAME=dbname
DB_USER=dbuser
DB_PASS=dbpassword

# etc ..

Backup

Here is how to backup the DB (mysql, mariadb)

/usr/bin/mysqldump \
	-u $_DB_USER \
	-p$_DB_PASSWORD \
	$_DB_NAME \
	> ${DB_BACKUP_FILE}

And here is how to backup a WordPress instance.

# WP_DATA_DIR=/var/www/html/wp-content
tar czpf $BAK_TARGET_DIR/$WP_BACKUP_NAME.tar.gz $WP_DATA_DIR

Note: I usually backup only the wp-content folder, and not the full content of server’s /var/www/html/

Restore

Database

cat "$DB_BACKUP_FILE" | /usr/bin/mysql -u$_DB_USER -p$_DB_PASSWORD $_DB_NAME  

WordPress files

# WP_DATA_DIR=/var/www/html/wp-content
tar xzpf backup/$_WP_BACKUP_NAME -C / #$WP_DATA_DIR

Backup/Restore on Docker

In this section, we’ll see how to backup DB and filesystem of a wordpress instance running on docker. The main big difference with the bash version, is that we need to spin a container to backup/restore.

Bash inside docker

To execute a script in a container, we first need to get the container id, using docker ps.

Then, below you see a trivial way to execute a command inside a container.

docker exec -it <CONTAINER_ID> bash -l

Of course, we won’t backup via bash in the container, but this might be useful just to get a grip of the situation.

Backup

Here is how to backup the db on a running container.

# perform database backup
docker exec $DB_IMAGE_NAME /usr/bin/mysqldump \
	-u $DB_USER \
	-p$DB_PASSWORD \
	$DB_NAME \
	> ${DB_BACKUP_FILE}

• DB_IMAGE_NAME : name of the image running the container

And here is how we backup the WP data.

# wordpress data backup
docker run --rm --volumes-from $WP_IMAGE_NAME \
	-v $BAK_TARGET_DIR:/backup ubuntu \
	tar czpf /backup/$WP_BACKUP_NAME.tar.gz $WP_DATA_DIR

• WP_IMAGE_NAME : name of the image running the container
• WP_DATA_DIR : directory you want to backup inside the container, i.e. /var/www/site/public_html

Restore

Here is the restore of the DB.

# restore database
cat "$DB_SOURCE_FILE" | docker exec -i $DB_IMAGE_NAME \
	/usr/bin/mysql -u$DB_USER -p$DB_PASSWORD $DB_NAME  

And this is how I restore the WordPress data

# restore wordpress files
docker run --rm \
	--volumes-from $WP_IMAGE_NAME \
	-v $BAK_SOURCE_DIR:/backup \
	ubuntu \
	tar xzpf backup/$WP_BACKUP_NAME -C / #$WP_DATA_DIR

Conclusion

This approach works and is the actual method I am using for this site, although I automated a bit the process.

References

• https://wordpress.org/support/article/backing-up-your-database/