Load balancing preprod API back servers

deeployer.libsonnet

@@ -7,10 +7,10 @@
   "$schema": "https://raw.githubusercontent.com/thecodingmachine/deeployer/master/deeployer.schema.json",
   "version": "1.0",
   "containers": {
-     "back": {
+     "back1": {
        "image": "thecodingmachine/workadventure-back:"+tag,
        "host": {
-         "url": "api."+url,
+         "url": "api1."+url,
          "https": "enable",
          "containerPort": 8080
        },
@@ -25,6 +25,24 @@
          "ADMIN_API_URL": adminUrl,
        } else {}
      },
+     "back2": {
+            "image": "thecodingmachine/workadventure-back:"+tag,
+            "host": {
+              "url": "api2."+url,
+              "https": "enable",
+              "containerPort": 8080
+            },
+            "ports": [8080, 50051],
+            "env": {
+              "SECRET_KEY": "tempSecretKeyNeedsToChange",
+              "ADMIN_API_TOKEN": env.ADMIN_API_TOKEN,
+              "JITSI_ISS": env.JITSI_ISS,
+              "JITSI_URL": env.JITSI_URL,
+              "SECRET_JITSI_KEY": env.SECRET_JITSI_KEY,
+            } + if adminUrl != null then {
+              "ADMIN_API_URL": adminUrl,
+            } else {}
+          },
      "pusher": {
             "replicas": 2,
             "image": "thecodingmachine/workadventure-pusher:"+tag,
@@ -38,7 +56,7 @@
               "ADMIN_API_TOKEN": env.ADMIN_API_TOKEN,
               "JITSI_ISS": env.JITSI_ISS,
               "JITSI_URL": env.JITSI_URL,
-              "API_URL": "back:50051",
+              "API_URL": "back1:50051,back2:50051",
               "SECRET_JITSI_KEY": env.SECRET_JITSI_KEY,
             } + if adminUrl != null then {
               "ADMIN_API_URL": adminUrl,
@@ -100,7 +118,35 @@
     },
     k8sextension(k8sConf)::
         k8sConf + {
-          back+: {
+          back1+: {
+            deployment+: {
+              spec+: {
+                template+: {
+                  metadata+: {
+                    annotations+: {
+                      "prometheus.io/port": "8080",
+                      "prometheus.io/scrape": "true"
+                    }
+                  }
+                }
+              }
+            }
+          },
+          back2+: {
+            deployment+: {
+              spec+: {
+                template+: {
+                  metadata+: {
+                    annotations+: {
+                      "prometheus.io/port": "8080",
+                      "prometheus.io/scrape": "true"
+                    }
+                  }
+                }
+              }
+            }
+          },
+          pusher+: {
             deployment+: {
               spec+: {
                 template+: {