Can you describe what steps you took to upgrade?
Unknown MySQL server host ‘mysql’
By default the docker-compose file will create an alias “mysql” for the database container inside the docker network. If this host cannot be found either the DB container has failed to start, or there is something wrong with the configuration somewhere.
In your case it looks like MySQL crashed:
cms-db_1 | 2023-12-04 09:57:53+00:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.35-1.el8 started.
cms-db_1 | 2023-12-04 09:57:56+00:00 [Note] [Entrypoint]: Switching to dedicated user 'mysql'
cms-db_1 | 2023-12-04 09:57:57+00:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.35-1.el8 started.
cms-db_1 | '/var/lib/mysql/mysql.sock' -> '/var/run/mysqld/mysqld.sock'
cms-db_1 | 2023-12-04T09:57:57.706101Z 0 [Warning] [MY-011068] [Server] The syntax '--skip-host-cache' is deprecated and will be removed in a future release. Please use SET GLOBAL host_cache_size=0 instead.
cms-db_1 | 2023-12-04T09:57:57.708353Z 0 [System] [MY-010116] [Server] /usr/sbin/mysqld (mysqld 8.0.35) starting as process 1
cms-db_1 | 2023-12-04T09:57:57.802715Z 1 [System] [MY-011012] [Server] Starting upgrade of data directory.
cms-db_1 | 2023-12-04T09:57:57.802835Z 1 [System] [MY-013576] [InnoDB] InnoDB initialization has started.
cms-db_1 | 2023-12-04T09:57:59.534842Z 1 [ERROR] [MY-012526] [InnoDB] Upgrade is not supported after a crash or shutdown with innodb_fast_shutdown = 2. This redo log was created with MySQL 5.7.38, and it appears logically non empty. Please follow the instructions at http://dev.mysql.com/doc/refman/8.0/en/upgrading.html
cms-db_1 | 2023-12-04T09:57:59.534885Z 1 [ERROR] [MY-012930] [InnoDB] Plugin initialization aborted with error Generic error.
cms-db_1 | 2023-12-04T09:57:59.969225Z 1 [ERROR] [MY-011013] [Server] Failed to initialize DD Storage Engine.
cms-db_1 | 2023-12-04T09:57:59.969483Z 0 [ERROR] [MY-010020] [Server] Data Dictionary initialization failed.
cms-db_1 | 2023-12-04T09:57:59.969515Z 0 [ERROR] [MY-010119] [Server] Aborting
cms-db_1 | 2023-12-04T09:57:59.970012Z 0 [System] [MY-010910] [Server] /usr/sbin/mysqld: Shutdown complete (mysqld 8.0.35) MySQL Community Server - GPL.
In this case what you’re likely have to do is to restore a backup of your database into a new MySQL 8.0 container. You’d down the containers, delete the contents of the shared/db folder (not the database backup), and then follow the instructions for moving to docker in the installation guide.
Obviously make sure you have a backup first!