The home directory inside which Python MySQL settings will be stored, which Ansible will use when connecting to MySQL. This should be the home directory of the user which runs this Ansible role.
Whether the global my.cnf should be overwritten each time this role is run. Setting this to `no` tells Ansible to only create the `my.cnf` file if it doesn't exist. This should be left at its default value (`yes`) if you'd like to use this role's variables to configure MySQL.
The MySQL databases to create. A database has the values `name`, `encoding` (defaults to `utf8`), `collation` (defaults to `utf8_general_ci`) and `replicate` (defaults to `1`, only used if replication is configured). The formats of these are the same as in the `mysql_db` module.
The MySQL users and their privileges. A user has the values `name`, `host` (defaults to `localhost`), `password` and `priv` (defaults to `*.*:USAGE`). The formats of these are the same as in the `mysql_user` module.
(OS-specific, RedHat/CentOS defaults listed here) Packages to be installed. In some situations, you may need to add additional packages, like `mysql-devel`.
mysql_enablerepo: ""
(RedHat/CentOS only) If you have enabled any additional repositories (might I suggest geerlingguy.repo-epel or geerlingguy.repo-remi), those repositories can be listed under this variable (e.g. `remi,epel`). This can be handy, as an example, if you want to install later versions of MySQL.
The rest of the settings in `defaults/main.yml` control MySQL's memory usage. The default values are tuned for a server where MySQL can consume ~512 MB RAM, so you should consider adjusting them to suit your particular server better.
Replication settings. Set `mysql_server_id` and `mysql_replication_role` by server (e.g. the master would be ID `1`, with the `mysql_replication_role` of `master`, and the slave would be ID `2`, with the `mysql_replication_role` of `slave`). The `mysql_replication_user` uses the same keys as `mysql_users`, and is created on master servers, and used to replicate on all the slaves.