Description of problem:

Related to https://bugzilla.redhat.com/show_bug.cgi?id=1247924#c13

MariaDB on undercloud controller max_connections should be based on core count or connection limits will be exceeded during large, multiple deployments.

Version-Release number of selected component (if applicable):

python-rdomanager-oscplugin-0.0.8-44.el7ost.noarch


How reproducible:


Steps to Reproduce:
1. Deploy undercloud
2. mysql -e "SHOW GLOBAL VARIABLES LIKE 'max_connections'"

Actual results:


Expected results:


Additional info: 

Workaround to change on already deployed undercloud:

[root@rhos0 ~]# mysql -e "SHOW STATUS WHERE variable_name = 'Threads_connected'"
+-------------------+-------+
| Variable_name     | Value |
+-------------------+-------+
| Threads_connected | 519   |
+-------------------+-------+

[root@rhos0 ~]# mysql -e "SET GLOBAL max_connections = 4096"

[root@rhos0 ~]# mysql -e "SHOW GLOBAL VARIABLES LIKE 'max_connections'"
+-----------------+-------+
| Variable_name   | Value |
+-----------------+-------+
| max_connections | 4096  |
+-----------------+-------+

Workaround to change for restarts and boot:

[root@rhos0 ~]# sed -i 's/max_connections =.*$/max_connections = 4096/' /etc/my.cnf.d/server.cnf 

[root@rhos0 ~]# grep max_connections /etc/my.cnf.d/server.cnf 
max_connections = 4096

NOTE: Normally HAproxy max_conn should be greater than or equal to MariaDB max_connections, but no HAproxy on undercloud so max_conn does not need to be adjusted.