Improve MySQL Galera password handling - use dedicated not root credentials

Prod related PROD-23926 (PROD:23926)

Change-Id: I1c09b54e22ac274336597fff6582a5b997f13ea4
diff --git a/metadata/service/master/container.yml b/metadata/service/master/container.yml
index f4957a6..9711b48 100644
--- a/metadata/service/master/container.yml
+++ b/metadata/service/master/container.yml
@@ -3,6 +3,8 @@
     galera_server_cluster_name: galeracluster
     galera_server_bind_port: 3306
     galera_server_admin_user: root
+    galera_server_sst_user: sstuser
+    galera_server_sst_password: ${_param:galera_server_admin_password}
     galera_max_connections: 20000
     galera_innodb_buffer_pool_size: 3138M
     galera_innodb_read_io_threads: 8
@@ -29,6 +31,9 @@
                 admin:
                   user: ${_param:galera_server_admin_user}
                   password: ${_param:galera_server_admin_password}
+                sst:
+                  user: ${_param:galera_server_sst_user}
+                  password: ${_param:galera_server_sst_password}
                 members:
                 - host: ${_param:mysql_service_host01}
                   port: 4567
@@ -51,3 +56,12 @@
                   host: localhost
                 - name: haproxy
                   host: '%'
+                - name: ${_param:galera_server_sst_user}
+                  password: ${_param:galera_server_sst_password}
+                  host: localhost
+                  database: '*.*'
+                  grants:
+                    - PROCESS
+                    - RELOAD
+                    - LOCK TABLES
+                    - REPLICATION CLIENT