Export envoy metrics for mysql service

databases/mysql.nomad

@@ -19,6 +19,9 @@ job "mysql-server" {
         host_network = "loopback"
         to = 3306
       }
+      port "envoy_metrics" {
+        to = 9123
+      }
     }
 
     volume "mysql-data" {
@@ -35,6 +38,10 @@ job "mysql-server" {
         sidecar_service {
           proxy {
             local_service_port = 3306
+
+            config {
+              envoy_prometheus_bind_addr = "0.0.0.0:9123"
+            }
           }
         }
 
@@ -45,6 +52,10 @@ job "mysql-server" {
           }
         }
       }
+
+      meta {
+        envoy_metrics_addr = "${NOMAD_ADDR_envoy_metrics}"
+      }
     }
 
     task "mysql-server" {