Unable to connect to mariadb suddenly - Error 500

[rickygarg]

I'm suddenly facing an issue today morning similar to #395 and #636 with the following logs:

PHP Fatal error: Uncaught Doctrine\\DBAL\\DBALException: Failed to connect to the database: An exception occured in driver: SQLSTATE[HY000] [2002] Connection refused in /var/www/html/lib/private/DB/Connection.php:64\nStack trace:\n#0 /var/www/html/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(429): OC\\DB\\Connection->connect()\n#1 /var/www/html/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(389): Doctrine\\DBAL\\Connection->getDatabasePlatformVersion()\n#2 /var/www/html/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(328): Doctrine\\DBAL\\Connection->detectDatabasePlatform()\n#3 /var/www/html/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(623): Doctrine\\DBAL\\Connection->getDatabasePlatform()\n#4 /var/www/html/lib/private/DB/Connection.php(151): Doctrine\\DBAL\\Connection->setTransactionIsolation(2)\n#5 /var/www/html/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/DriverManager.php(172): OC\\DB\\Connection->__construct(Array, Object(Doctrine\\DBAL\\Driver\\PDOMySql\\Driver), Object(Doctrine\\DBAL\\Configuration), Object(D in /var/www/html/lib/private/DB/Connection.php on line 64

However, manually changing the my.cnf (https://help.nextcloud.com/t/nextcloud-13-php-7-1-mysql-8-error-500/34443), or adding a command on docker-compose (#395) doesn't resolve or change the error log:

command: --default_authentication_plugin=mysql_native_password

I run nextcloud through the official instructions on help, and can access the mariadb instance normally from the nextcloud container using a mysql client (freshly installed to test). As mentioned, I didn't update the image - the issue suddenly propped up today morning. However, I tried afterwards a docker pull nextcloud:latest but the issue prevails.

[rickygarg]

This is resolved. I had used the Nextcloud wizard to setup the database connection where I provided the docker IP address for the DB container. On a container restart, docker assigned new IP addresses making the db address in config.php incorrect. I have now replaced the docker internal IP address with the container name 'db'.

Not sure if I missed this from the documentation, as I already had a link to the db in my docker-compose.yml:

app: container_name: nextcloud image: nextcloud:latest expose: - "80" links: - db depends_on: - "nginx-proxy" - "db"