Healthchecks for NGINX in nginx-http-dep.yaml and dev-setup/nginx-http.yaml (#1679)

docs/server/source/production-deployment-template/node-on-kubernetes.rst

@@ -133,11 +133,6 @@ Step 4.1: Vanilla NGINX
      ``cluster-frontend-port`` in the ConfigMap above. This is the
      ``public-cluster-port`` in the file which is the ingress in to the cluster.
 
-   * Set ``ports[1].port`` and ``ports[1].targetPort`` to the value set in the
-     ``cluster-health-check-port`` in the ConfigMap above. This is the
-     ``public-health-check-port`` in the file which is the health check port.
-     Note: This will be removed in the future.
-
    * Start the Kubernetes Service:
 
      .. code:: bash

k8s/configuration/config-map.yaml

@@ -16,6 +16,8 @@ data:
 
   # cluster-health-check-port is the port number on which an external load
   # balancer can check the status/liveness of the external/public server.
+  # In our deployment, Kubernetes sends 'livenessProbes' to this port and
+  # interprets a successful response as a 'healthy' service.
   cluster-health-check-port: "8888"
 
   # cluster-dns-server-ip is the IP of the DNS server. A Kubernetes deployment

k8s/dev-setup/nginx-http.yaml

@@ -18,10 +18,6 @@ spec:
     targetPort: 80
     name: ngx-public-bdb-port-http
     protocol: TCP
-  - port: 8080
-    targetPort: 8080
-    name: public-health-check-port
-    protocol: TCP
   - port: 27017
     targetPort: 27017
     name: ngx-public-mdb-port
@@ -68,10 +64,18 @@ spec:
         ports:
         - containerPort: 27017
           protocol: TCP
-        - containerPort: 8080
-          protocol: TCP
         - containerPort: 80
           protocol: TCP
+        - containerPort: 8080
+          protocol: TCP
+        livenessProbe:
+          httpGet:
+            path: /health
+            port: 8080
+          initialDelaySeconds: 15
+          periodSeconds: 15
+          failureThreshold: 3
+          timeoutSeconds: 10
         resources:
           limits:
             cpu: 200m

k8s/nginx-http/container/nginx.conf.template

@@ -1,7 +1,7 @@
 # Frontend API server that:
 # 1. Forwards BDB HTTP & WS requests to BDB backend.
 # 2. Forwards MDB TCP connections to MDB backend.
-# 3. Does health check with LB (optional).
+# 3. Does health check with LB.
 
 worker_processes 2;
 daemon off;
@@ -103,14 +103,14 @@ http {
     }
   }
 
-#  # Frontend server for the load balancer to respond to health checks.
-#  server {
-#    listen HEALTH_CHECK_PORT;
-#
-#    location = /health {
-#      return 200;
-#    }
-#  }
+  # Frontend server for the load balancer to respond to health checks.
+  server {
+    listen HEALTH_CHECK_PORT;
+
+    location = /health {
+      return 200;
+    }
+  }
 }
 
 # NGINX stream block for TCP and UDP proxies. Used to proxy MDB TCP

k8s/nginx-http/nginx-http-dep.yaml

@@ -65,8 +65,17 @@ spec:
           protocol: TCP
         - containerPort: "<cluster-health-check-port from ConfigMap>"
           protocol: TCP
+          name: ngx-health
         - containerPort: "<cluster-frontend-port from ConfigMap>"
           protocol: TCP
+        livenessProbe:
+          httpGet:
+            path: /health
+            port: ngx-health
+          initialDelaySeconds: 15
+          periodSeconds: 15
+          failureThreshold: 3
+          timeoutSeconds: 10
         resources:
           limits:
             cpu: 200m

k8s/nginx-http/nginx-http-svc.yaml

@@ -17,8 +17,4 @@ spec:
     targetPort: "<cluster-frontend-port from ConfigMap>"
     name: public-cluster-port
     protocol: TCP
-  - port: "<cluster-health-check-port from ConfigMap>"
-    targetPort: "<cluster-health-check-port from ConfigMap>"
-    name: public-health-check-port
-    protocol: TCP
   type: LoadBalancer

k8s/nginx-https/container/nginx.conf.template

@@ -3,8 +3,7 @@
 # 2. Forwards BDB HTTP requests to OpenResty backend.
 # 3. Forwards BDB WS requests to BDB backend.
 # 4. Forwards MDB TCP connections to MDB backend.
-# 5. Forwards requests from 3scale to OpenResty backend.
-# 6. Does health check with LB.
+# 5. Does health check with LB.
 
 worker_processes 2;
 daemon off;