SadServers - Linux & DevOps Troubleshooting Interviews

#	Name	Level	Time	Type
1	"Bern": Docker web container can't connect to db container.	Hard	20 m	Fix	"Bern": Docker web container can't connect to db container. Scenario: "Bern": Docker web container can't connect to db container. Level: Hard Type: Fix Access: Email Description: There are two Docker containers running, a web application (Wordpress or WP) and a database (MariaDB) as back-end, but if we look at the web page, we see that it cannot connect to the database. `curl -s localhost:80 \|tail -4` returns: `<body id="error-page"> <div class="wp-die-message"><h1>Error establishing a database connection</h1></div></body> </html>` This is not a Wordpress code issue (the image is :latest with some network utilities added). What you need to know is that WP uses "WORDPRESS_DB_" environment variables to create the MySQL connection string. See the ./html/wp-config.php WP config file for example (from /home/admin). Test: `sudo docker exec wordpress mysqladmin -h mysql -u root -ppassword ping` . The wordpress container is able to connect to the database in the mariadb container and returns `mysqld is alive`. Time to Solve: 20 minutes.

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