Without host=$host
DBI connect('mysql_ssl=1;database=****;mysql_read_default_file=/tmp/my.cnf;mysql_read_default_group=test_group','',...) failed: Can't connect to local MySQL server through socket '/var/run/mysql.sock' (2) at /tmp/test_db.pl line 12.

With host=$host
$dbh = DBI::db=HASH(0xa00318a18)