dovecot: dict: Error: mysql: Connect failed to localhost (mail): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (13) - waiting for 1 seconds before retry
The problem is that Selinux prevents dovecot connecting to mysql socket. I was unable to find simple solution by setting some setsebol parameter, so I went through the audit.log with audit2allow.
Solution:
Create dovecot2mysql.te file under /etc/selinux:
cat > /etc/selinux/dovecot2mysql.te module dovecot2mysqldb 1.0.0; require { type dovecot_t; type dovecot_deliver_t; type var_t; type mysqld_db_t; type mysqld_t; type mysqld_var_run_t; type usr_t; class file { rename read create write getattr link unlink open }; class dir search; class unix_stream_socket connectto; class sock_file write; class file { read getattr open }; } allow dovecot_deliver_t var_t:file { rename read create write getattr link unlink open }; allow dovecot_t mysqld_db_t:dir search; allow dovecot_t mysqld_t:unix_stream_socket connectto; allow dovecot_t mysqld_var_run_t:sock_file write; allow dovecot_t usr_t:file { read getattr open }; cat >/etc/selinux/sel.sh <<EOF name=\${1%%.*} echo "\$name" checkmodule -M -m -o \$name.mod \$name.te \ && semodule_package -o \$name.pp -m \$name.mod \ && /usr/sbin/semodule -i \$name.pp EOF chmod 700 /etc/selinux/sel.sh /etc/selinux/sel.sh /etc/selinux/dovecot2mysql.te