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mysqlcentosselinux

Unknown/unsupported storage engine: InnoDB

I'm setting up a replication server and when I try to start the mysql service for the first time, it fails: 

[root@ravioli mysql]# service mysqld start
MySQL Daemon failed to start.
Starting mysqld:                                           [FAILED]
[root@ravioli mysql]# tail /var/log/mysqld.log 
151013 13:41:27 [ERROR] Plugin 'InnoDB' init function returned error.
151013 13:41:27 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
/usr/libexec/mysqld: File '/databases/mysql/mysql_slow_queries.log' not found (Errcode: 13)
151013 13:41:27 [ERROR] Could not use /databases/mysql/mysql_slow_queries.log for logging (error 13). Turning logging off for the whole duration of the MySQL server process. To turn it on again: fix the cause, shutdown the MySQL server and restart it.
151013 13:41:27 [ERROR] Unknown/unsupported storage engine: InnoDB
151013 13:41:27 [ERROR] Aborting

151013 13:41:27 [Note] /usr/libexec/mysqld: Shutdown complete

151013 13:41:27 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended

I confirmed that user mysql sees and is able to write to /databases/mysql/mysql_slow_queries.log.

Then I checked getenforce and see it is set to Enforcing.

How do I configure MySQL to play nicely with SELinux?

Solution

  • Ok this was actually much easier than expected.

    By default SELinux is Enforcing, which prevents unexpected writes on the filesystem. I just needed to tell SELinux that it's OK for MySQL to write to a non-standard directory. To wit: 

    [root@ravioli]# semanage fcontext -a -t mysqld_db_t "/databases/mysql(/.*)?"
-bash: semanage: command not found.

    Derp. To install semanage, use this: 

    yum install policycoreutils-python

    Now run the command again. This may take a few moments...

    [root@ravioli]# semanage fcontext -a -t mysqld_db_t "/databases/mysql(/.*)?"

    Check to see that SELinux is configured for this new directory by looking at this config file: 

    [root@ravioli]#  grep -i mysql /etc/selinux/targeted/contexts/files/file_contexts.local

/databases/mysql(/.*)?    system_u:object_r:mysqld_db_t:s0

    Additional directories can be added, for instance if you have a dedicated tmp directory somewhere. 

    [root@ravioli]# semanage fcontext -a -t mysqld_db_t "/databases/mysql_tmp(/.*)?"

    Check the config again: 

    [root@ravioli]# grep -i mysql /etc/selinux/targeted/contexts/files/file_contexts.local

/databases/mysql(/.*)?    system_u:object_r:mysqld_db_t:s0
/databases/mysql_tmp(/.*)?    system_u:object_r:mysqld_db_t:s0

    Finally, update the permissions using restorecron

    restorecon -R -v /www/databases/mysql/

    and in my setup, 

    restorecon -R -v /www/databases/mysql_tmp/

    Now issue: 

    service mysqld start

    Bene. 

    Starting mysqld:         [  OK  ]