MySQL / MariaDB SSL Connection without verify CA
Its possible to authenticate with SSL without verify the client certificate with server CA (ssl_ca) ?


No, you will need to create a CA, generate a Certificate Generation Request (CSR), then generate a client certificate from the CA.  Both sides of the connection will need the client cert and the CA.  

You can reuse the same client certificate for all clients.  Or, when creating the user you can use REQUIRE CN= to enforce the user to connect with a specific certificate (this requires a different step when generating the client cert).  


I recommend using passwords as well for authentication
Pay attention to the expiration date of your CA.  Updating the CA or client certs requires a restart of MySQL
You can have more than one CA in your ssl_ca file to allow for a transition period if you are required to rotate CAs.
The CN for your CA cannot be the same as your client cert.  You will tear your hair out trying to figure out what you did wrong if you do this.