<p>I have been trying to test minikube to create a demo application with three services. The idea is to have a web UI which communicates with the other services. Each service will be written in different languages: nodejs, python and go.</p>

<p>I created 3 docker images, one for each app and tested the code, basically they provided a very simple REST endpoints. After that, I deployed them using minikube. Below is my current deployment yaml file:</p>

<pre><code>---
apiVersion: v1
kind: Namespace
metadata:
  name: ngci

---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: web-gateway
  namespace: ngci
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: web-gateway
    spec:
      containers:
      - env:
        - name: VCSA_MANAGER
          value: http://vcsa-manager-service:7070
        name: web-gateway
        image: silvam11/web-gateway
        imagePullPolicy: Never
        ports:
          - containerPort: 8080 
        readinessProbe:
          httpGet:
            path: /status
            port: 8080
          periodSeconds: 5           

---
apiVersion: v1
kind: Service
metadata:
  name: web-gateway-service
  namespace: ngci
spec:
  selector:
    app: web-gateway
  ports:
    - protocol: "TCP"
      # Port accessible inside cluster
      port: 8080
      # Port forward to inside the pod
      #targetPort did not work with nodePort, why?
      #targetPort: 9090
      # Port accessible outside cluster
      nodePort: 30001
      #name: grpc
  type: LoadBalancer

---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: vcsa-manager
  namespace: ngci
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: vcsa-manager
    spec:
      containers:
        - name: vcsa-manager
          image: silvam11/vcsa-manager
          imagePullPolicy: Never
          ports:
            - containerPort: 8080

---
apiVersion: v1
kind: Service
metadata:
  name: vcsa-manager-service
  namespace: ngci
spec:
  selector:
    app: vcsa-manager
  ports:
    - protocol: "TCP"
      # Port accessible inside cluster
      port: 7070
      # Port forward to inside the pod
      #targetPort did not work with nodePort, why?
      targetPort: 9090
      # Port accessible outside cluster
      #nodePort: 30001
      #name: grpc

---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: repo-manager
  namespace: ngci
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: repo-manager
    spec:
      containers:
        - name: repo-manager
          image: silvam11/repo-manager
          imagePullPolicy: Never
          ports:
            - containerPort: 8000

---
apiVersion: v1
kind: Service
metadata:
  name: repo-manager-service
  namespace: ngci
spec:
  selector:
    app: repo-manager
  ports:
    - protocol: "TCP"
      # Port accessible inside cluster
      port: 9090
      # Port forward to inside the pod
      #targetPort did not work with nodePort, why?
      #targetPort: 9090
      # Port accessible outside cluster
      #nodePort: 30001
      #name: grpc
</code></pre>

<p>As you can see, I created there services but only the web-gateway is defined as LoadBalancer type. It provides two endpoints. One named /status which allows me to test the service is up and running and reachable.</p>

<p>The second endpoint, named /user, communicates with another k8s service. The code is very simple:</p>

<pre><code>app.post('/user', (req, res) =&gt; {
  console.log("/user called.");
  console.log("/user req.body : " + req.body);

  if(!req || !req.body)
  {
     var errorMsg = "Invalid argument sent";
     console.log(errorMsg);
     return res.status(500).send(errorMsg);
  }

  **console.log("calling " + process.env.VCSA_MANAGER);
  const options = {
    url: process.env.VCSA_MANAGER,
    method: 'GET',
    headers: {
      'Accept': 'application/json'
    }
  };**

  request(options, function(err, resDoc, body) {
    console.log("callback : " + body);
    if(err)
    {
      console.log("ERROR: " + err);
      return res.send(err);
    }

    console.log("statusCode : " + resDoc.statusCode);
    if(resDoc.statusCode != 200)
    {
      console.log("ERROR code: " + res.statusCode);
      return res.status(500).send(resDoc.statusCode);
    }

    return res.send({"ok" : body});
  });

});
</code></pre>

<p>The main idea of this snippet is to use the environment variable process.env.VCSA_MANAGER to send a request to the other service. This varaible was defined on my k8s deployment yaml file as <em><a href="http://vcsa-manager-service:7070" rel="noreferrer">http://vcsa-manager-service:7070</a></em></p>

<p>The issue is that, this request returns a connection error. Initially I thought that it would be a DNS issue but it seems that the web-gateway pod can resolve the name:</p>

<pre><code>kubectl exec -it web-gateway-7b4689bff9-rvbbn -n ngci -- ping vcsa-manager-service

PING vcsa-manager-service.ngci.svc.cluster.local (10.99.242.121): 56 data bytes
</code></pre>

<p>The ping command from the web-gateway pod resolved the dns correctly. The IP is the correct, as can be seen below:</p>

<pre><code>kubectl get svc -n ngci

NAME                   TYPE           CLUSTER-IP       EXTERNAL-IP   PORT(S)          AGE
repo-manager-service   ClusterIP      10.102.194.179   &lt;none&gt;        9090/TCP         35m
vcsa-manager-service   ClusterIP      10.99.242.121    &lt;none&gt;        7070/TCP         35m
web-gateway-service    LoadBalancer   10.98.128.210    &lt;pending&gt;     8080:30001/TCP   35m
</code></pre>

<p>Also, as suggested, the describe of them</p>

<pre><code>kubectl describe pods -n ngci
Name:           repo-manager-6cf98f5b54-pd2ht
Namespace:      ngci
Node:           minikube/10.0.2.15
Start Time:     Wed, 09 May 2018 17:53:54 +0100
Labels:         app=repo-manager
                pod-template-hash=2795491610
Annotations:    &lt;none&gt;
Status:         Running
IP:             172.17.0.10
Controlled By:  ReplicaSet/repo-manager-6cf98f5b54
Containers:
  repo-manager:
    Container ID:   docker://d2d54e42604323c8a6552b3de6e173e5c71eeba80598bfc126fbc03cae93d261
    Image:          silvam11/repo-manager
    Image ID:       docker://sha256:dc6dcbb1562cdd5f434f86696ce09db46c7ff5907b991d23dae08b2d9ed53a8f
    Port:           8000/TCP
    Host Port:      0/TCP
    State:          Running
      Started:      Thu, 10 May 2018 10:32:49 +0100
    Last State:     Terminated
      Reason:       Error
      Exit Code:    137
      Started:      Wed, 09 May 2018 17:53:56 +0100
      Finished:     Wed, 09 May 2018 18:31:24 +0100
    Ready:          True
    Restart Count:  1
    Environment:    &lt;none&gt;
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-tbkms (ro)
Conditions:
  Type           Status
  Initialized    True 
  Ready          True 
  PodScheduled   True 
Volumes:
  default-token-tbkms:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  default-token-tbkms
    Optional:    false
QoS Class:       BestEffort
Node-Selectors:  &lt;none&gt;
Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s
                 node.kubernetes.io/unreachable:NoExecute for 300s
Events:
  Type    Reason                 Age   From               Message
  ----    ------                 ----  ----               -------
  Normal  Scheduled              16h   default-scheduler  Successfully assigned repo-manager-6cf98f5b54-pd2ht to minikube
  Normal  SuccessfulMountVolume  16h   kubelet, minikube  MountVolume.SetUp succeeded for volume "default-token-tbkms"
  Normal  Pulled                 16h   kubelet, minikube  Container image "silvam11/repo-manager" already present on machine
  Normal  Created                16h   kubelet, minikube  Created container
  Normal  Started                16h   kubelet, minikube  Started container
  Normal  SuccessfulMountVolume  3m    kubelet, minikube  MountVolume.SetUp succeeded for volume "default-token-tbkms"
  Normal  SandboxChanged         3m    kubelet, minikube  Pod sandbox changed, it will be killed and re-created.
  Normal  Pulled                 3m    kubelet, minikube  Container image "silvam11/repo-manager" already present on machine
  Normal  Created                3m    kubelet, minikube  Created container
  Normal  Started                3m    kubelet, minikube  Started container


Name:           vcsa-manager-8696b44dff-mzq5q
Namespace:      ngci
Node:           minikube/10.0.2.15
Start Time:     Wed, 09 May 2018 17:53:54 +0100
Labels:         app=vcsa-manager
                pod-template-hash=4252600899
Annotations:    &lt;none&gt;
Status:         Running
IP:             172.17.0.14
Controlled By:  ReplicaSet/vcsa-manager-8696b44dff
Containers:
  vcsa-manager:
    Container ID:   docker://3e19fd8ca21a678e18eda3cb246708d10e3f1929a31859f0bb347b3461761b53
    Image:          silvam11/vcsa-manager
    Image ID:       docker://sha256:1a9cd03166dafceaee22586385ecda1c6ad3ed095b498eeb96771500092b526e
    Port:           8080/TCP
    Host Port:      0/TCP
    State:          Running
      Started:      Thu, 10 May 2018 10:32:54 +0100
    Last State:     Terminated
      Reason:       Error
      Exit Code:    2
      Started:      Wed, 09 May 2018 17:53:56 +0100
      Finished:     Wed, 09 May 2018 18:31:15 +0100
    Ready:          True
    Restart Count:  1
    Environment:    &lt;none&gt;
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-tbkms (ro)
Conditions:
  Type           Status
  Initialized    True 
  Ready          True 
  PodScheduled   True 
Volumes:
  default-token-tbkms:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  default-token-tbkms
    Optional:    false
QoS Class:       BestEffort
Node-Selectors:  &lt;none&gt;
Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s
                 node.kubernetes.io/unreachable:NoExecute for 300s
Events:
  Type    Reason                 Age   From               Message
  ----    ------                 ----  ----               -------
  Normal  Scheduled              16h   default-scheduler  Successfully assigned vcsa-manager-8696b44dff-mzq5q to minikube
  Normal  SuccessfulMountVolume  16h   kubelet, minikube  MountVolume.SetUp succeeded for volume "default-token-tbkms"
  Normal  Pulled                 16h   kubelet, minikube  Container image "silvam11/vcsa-manager" already present on machine
  Normal  Created                16h   kubelet, minikube  Created container
  Normal  Started                16h   kubelet, minikube  Started container
  Normal  SuccessfulMountVolume  3m    kubelet, minikube  MountVolume.SetUp succeeded for volume "default-token-tbkms"
  Normal  SandboxChanged         3m    kubelet, minikube  Pod sandbox changed, it will be killed and re-created.
  Normal  Pulled                 3m    kubelet, minikube  Container image "silvam11/vcsa-manager" already present on machine
  Normal  Created                3m    kubelet, minikube  Created container
  Normal  Started                3m    kubelet, minikube  Started container


Name:           web-gateway-7b4689bff9-rvbbn
Namespace:      ngci
Node:           minikube/10.0.2.15
Start Time:     Wed, 09 May 2018 17:53:55 +0100
Labels:         app=web-gateway
                pod-template-hash=3602456995
Annotations:    &lt;none&gt;
Status:         Running
IP:             172.17.0.12
Controlled By:  ReplicaSet/web-gateway-7b4689bff9
Containers:
  web-gateway:
    Container ID:   docker://677fbcbc053c57e4aa24c66d7f27d3e9910bc3dbb5fda4c1cdf5f99a67dfbcc3
    Image:          silvam11/web-gateway
    Image ID:       docker://sha256:b80fb05c087934447c93c958ccef5edb08b7c046fea81430819823cc382337dd
    Port:           8080/TCP
    Host Port:      0/TCP
    State:          Running
      Started:      Thu, 10 May 2018 10:32:54 +0100
    Last State:     Terminated
      Reason:       Completed
      Exit Code:    0
      Started:      Wed, 09 May 2018 17:53:57 +0100
      Finished:     Wed, 09 May 2018 18:31:16 +0100
    Ready:          True
    Restart Count:  1
    Readiness:      http-get http://:8080/status delay=0s timeout=1s period=5s #success=1 #failure=3
    Environment:
      VCSA_MANAGER:  http://vcsa-manager-service:7070
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-tbkms (ro)
Conditions:
  Type           Status
  Initialized    True 
  Ready          True 
  PodScheduled   True 
Volumes:
  default-token-tbkms:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  default-token-tbkms
    Optional:    false
QoS Class:       BestEffort
Node-Selectors:  &lt;none&gt;
Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s
                 node.kubernetes.io/unreachable:NoExecute for 300s
Events:
  Type     Reason                 Age              From               Message
  ----     ------                 ----             ----               -------
  Normal   Scheduled              16h              default-scheduler  Successfully assigned web-gateway-7b4689bff9-rvbbn to minikube
  Normal   SuccessfulMountVolume  16h              kubelet, minikube  MountVolume.SetUp succeeded for volume "default-token-tbkms"
  Normal   Pulled                 16h              kubelet, minikube  Container image "silvam11/web-gateway" already present on machine
  Normal   Created                16h              kubelet, minikube  Created container
  Normal   Started                16h              kubelet, minikube  Started container
  Warning  Unhealthy              16h              kubelet, minikube  Readiness probe failed: Get http://172.17.0.13:8080/status: dial tcp 172.17.0.13:8080: getsockopt: connection refused
  Normal   SuccessfulMountVolume  3m               kubelet, minikube  MountVolume.SetUp succeeded for volume "default-token-tbkms"
  Normal   SandboxChanged         3m               kubelet, minikube  Pod sandbox changed, it will be killed and re-created.
  Normal   Pulled                 3m               kubelet, minikube  Container image "silvam11/web-gateway" already present on machine
  Normal   Created                3m               kubelet, minikube  Created container
  Normal   Started                3m               kubelet, minikube  Started container
  Warning  Unhealthy              3m (x3 over 3m)  kubelet, minikube  Readiness probe failed: Get http://172.17.0.12:8080/status: dial tcp 172.17.0.12:8080: getsockopt: connection refused
</code></pre>

<p>Here are the pods on ngci namespace:</p>

<pre><code>silvam11@ubuntu:~$ kubectl get pods -n ngci
NAME                            READY     STATUS    RESTARTS   AGE
repo-manager-6cf98f5b54-pd2ht   1/1       Running   1          16h
vcsa-manager-8696b44dff-mzq5q   1/1       Running   1          16h
web-gateway-7b4689bff9-rvbbn    1/1       Running   1          16h
</code></pre>

<p>What am I missing here? Is it a firewall?</p>

<p>Mauro</p>

<p>You misconfigured the port numbers.</p>
<p>First, <code>vcsa-manager</code> was exposed on port 8080; after that, you tried to map the service <code>vcsa-manager-service</code> to port 9090.
Then, <code>repo-manager</code> was exposed on port 8000; you commented <code>targetPort</code> and didn’t map the service to port.</p>
<p>You should map the service to the right ports.</p>
<p>Fixed config will look like:</p>
<pre><code>---
apiVersion: v1
kind: Namespace
metadata:
  name: ngci

---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: web-gateway
  namespace: ngci
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: web-gateway
    spec:
      containers:
      - env:
        - name: VCSA_MANAGER
          value: http://vcsa-manager-service:7070
        name: web-gateway
        image: silvam11/web-gateway
        imagePullPolicy: Never
        ports:
          - containerPort: 8080 
        readinessProbe:
          httpGet:
            path: /status
            port: 8080
          periodSeconds: 5           

---
apiVersion: v1
kind: Service
metadata:
  name: web-gateway-service
  namespace: ngci
spec:
  selector:
    app: web-gateway
  ports:
    - protocol: &quot;TCP&quot;
      port: 8080
      targetPort: 8080
      nodePort: 30001
      
  type: LoadBalancer

---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: vcsa-manager
  namespace: ngci
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: vcsa-manager
    spec:
      containers:
        - name: vcsa-manager
          image: silvam11/vcsa-manager
          imagePullPolicy: Never
          ports:
            - containerPort: 8080

---
apiVersion: v1
kind: Service
metadata:
  name: vcsa-manager-service
  namespace: ngci
spec:
  selector:
    app: vcsa-manager
  ports:
    - protocol: &quot;TCP&quot;
      port: 7070
      targetPort: 8080

---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: repo-manager
  namespace: ngci
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: repo-manager
    spec:
      containers:
        - name: repo-manager
          image: silvam11/repo-manager
          imagePullPolicy: Never
          ports:
            - containerPort: 8000

---
apiVersion: v1
kind: Service
metadata:
  name: repo-manager-service
  namespace: ngci
spec:
  selector:
    app: repo-manager
  ports:
    - protocol: &quot;TCP&quot;
      port: 9090
      targetPort: 8000
</code></pre>
<p>I’ve just fixed all ports in your config.</p>
