docker部署MySQL时无法启动的解决办法

一、安装环境 ubuntu18 + docker

docker run -itd --name mysql-server -v /home/docker/share/mysql-server/log/:/var/log:rw -v /home/docker/share/mysql-server/data/:/var/lib/mysql:rw -v /home/docker/share/mysql-server/conf:/etc/mysql:rw -v /etc/localtime:/etc/localtime:ro --restart=always -e MYSQL_ROOT_PASSWORD=123456 mysql

二、遇到无法启动的问题时，查看日志发现的错误

docker logs --tail -n mysql-server

1、You need to specify one of the following as an environment variable:

 - MYSQL_ROOT_PASSWORD
 - MYSQL_ALLOW_EMPTY_PASSWORD
 - MYSQL_RANDOM_ROOT_PASSWORD

2022-10-24 04:21:40+00:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.31-1.el8 started.
2022-10-24 04:21:40+00:00 [Note] [Entrypoint]: Switching to dedicated user 'mysql'
2022-10-24 04:21:40+00:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.31-1.el8 started.
2022-10-24 04:21:40+00:00 [ERROR] [Entrypoint]: Database is uninitialized and password option is not specified
    You need to specify one of the following as an environment variable:
    - MYSQL_ROOT_PASSWORD
    - MYSQL_ALLOW_EMPTY_PASSWORD
    - MYSQL_RANDOM_ROOT_PASSWORD
2022-10-24 04:21:41+00:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.31-1.el8 started.
2022-10-24 04:21:41+00:00 [Note] [Entrypoint]: Switching to dedicated user 'mysql'

解释： 由于mysql没有指定root的登录密码导致无法启动，默认mysql配置是不允许空密码登录的

原因：上面执行命令的时候写错了环境变量， MYSQL_SERVICE_PASSWORD 应该修改成 MYSQL_ROOT_PASSWORD

2、mysqld: Can't read dir of '/etc/mysql/conf.d/' (OS errno 2 - No such file or directory)

2022-10-24 04:17:09+00:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.31-1.el8 started.
2022-10-24 04:17:09+00:00 [ERROR] [Entrypoint]: mysqld failed while attempting to check config
    command was: mysqld --verbose --help --log-bin-index=/tmp/tmp.4hy30uDmqE
    mysqld: Can't read dir of '/etc/mysql/conf.d/' (OS errno 2 - No such file or directory)
mysqld: [ERROR] Stopped processing the 'includedir' directive in file /etc/my.cnf at line 36.
mysqld: [ERROR] Fatal error in defaults handling. Program aborted!
2022-10-24 04:17:13+00:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.31-1.el8 started.
2022-10-24 04:17:13+00:00 [ERROR] [Entrypoint]: mysqld failed while attempting to check config

解释：可能由于不同的mysql版本，/etc/mysql目录下的结构不一样

原因： 由于mysql的配置目录/etc/mysql下有两个空目录， 上面的执行命令仅挂载了当前目录，导致里面的两个目录没有权限挂载到宿主机内， 应该将挂载目录指定到具体的目录下： -v /home/docker/share/mysql-server/conf:/etc/mysql/conf.d:rw

3、mysqld: Can't create/write to file '/var/lib/mysql/is_writable' (OS errno 13 - Permission denied)

mysqld: Can't create/write to file '/var/lib/mysql/is_writable' (OS errno 13 - Permission denied)
2022-10-24T06:43:20.411035Z 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.
2022-10-24T06:43:20.411089Z 0 [System] [MY-013169] [Server] /usr/sbin/mysqld (mysqld 8.0.31) initializing of server in progress as process 40
2022-10-24T06:43:20.412290Z 0 [ERROR] [MY-010460] [Server] --initialize specified but the data directory exists and is not writable. Aborting.
2022-10-24T06:43:20.412294Z 0 [ERROR] [MY-013236] [Server] The designated data directory /var/lib/mysql/ is unusable. You can remove all files that the server added to it.
2022-10-24T06:43:20.412593Z 0 [ERROR] [MY-010119] [Server] Aborting
2022-10-24T06:43:20.412668Z 0 [System] [MY-010910] [Server] /usr/sbin/mysqld: Shutdown complete (mysqld 8.0.31)  MySQL Community Server - GPL.
2022-10-24 06:43:23+00:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.31-1.el8 started.
2022-10-24 06:43:24+00:00 [Note] [Entrypoint]: Initializing database files
mysqld: Can't create/write to file '/var/lib/mysql/is_writable' (OS errno 13 - Permission denied)

原因： 启动时没有足够的权限， /var/lib/mysql目录没有写权限， 可能是部署docker时指定了--user xxx某个权限不足的用户