Kubernetes pod Troubleshoot - kubernetes

Question

I deployed my container in kubernetes pod, andd pod and related services are up and running.
please find the below pod and deployment status of the pods
root#jenkins-linux-vm:/home/admin/kubernetes# kubectl get pods
NAME READY STATUS RESTARTS AGE
angular-deployment-5d5fbf967c-zvzvl 1/1 Running 0 70m
root#jenkins-linux-vm:/home/admin/kubernetes# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
angular-service NodePort 10.96.16.68 <none> 80:31000/TCP 79m
root#jenkins-linux-vm:/home/admin/kubernetes# kubectl get deployment
NAME READY UP-TO-DATE AVAILABLE AGE
angular-deployment 1/1 1 1 70m
please find the below curl access
root#jenkins-linux-vm:/home/admin/kubernetes# kubectl exec -it angular-deployment-5d5fbf967c-zvzvl curl 10.0.0.1:31000
curl: (7) Failed to connect to 10.0.0.1 port 31000: Connection refused
command terminated with exit code 7
Even though i am not able to access my application services in the browser as like below.
https://10.0.0.1:31000
apiVersion: apps/v1
kind: Deployment
metadata:
name: angular-deployment
spec:
selector:
matchLabels:
app: frontend-app
replicas: 1
template:
metadata:
labels:
app: frontend-app
spec:
containers:
- name: frontend-app
image: ${IMAGE_NAME}:${IMAGE_TAG}
ports:
- containerPort: 80
---
kind: Service
apiVersion: v1
metadata:
name: angular-service
spec:
selector:
app: frontend-app
ports:
- protocol: TCP
port: 80
targetPort: 80
nodePort: 31000
type: NodePort
root#jenkins-linux-vm:/home/admin# kubectl describe pod angular-deployment-556c47f666-9d2x4
Name: angular-deployment-556c47f666-9d2x4
Namespace: pre-release
Priority: 0
Node: poc-worker2/10.0.0.2
Start Time: Sat, 18 Jan 2020 08:47:35 +0000
Labels: app=frontend-app
pod-template-hash=556c47f666
Annotations: <none>
Status: Running
IP: 10.32.0.8
IPs:
IP: 10.32.0.8
Controlled By: ReplicaSet/angular-deployment-556c47f666
Containers:
frontend-app:
Container ID: docker://43fea22e4c1d49e0c94fc8aca3a4b41df44b5f91f45ea29ede263c5a6bcf6503
Image: frontend-app:future-master-fix-f2d2a8bd
Image ID: docker://sha256:0099587db89de9ef999a7d1f087d4781e73c491b17e89392e92b08d2f935ad27
Port: 80/TCP
Host Port: 0/TCP
State: Running
Started: Sat, 18 Jan 2020 08:47:40 +0000
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-r67p7 (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
default-token-r67p7:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-r67p7
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute for 300s
node.kubernetes.io/unreachable:NoExecute for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 21s default-scheduler Successfully assigned pre-release/angular-deployment-556c47f666-9d2x4 to poc-worker2
Normal Pulled 17s kubelet, poc-worker2 Container image "frontend-app:future-master-fix-f2d2a8bd" already present on machine
Normal Created 16s kubelet, poc-worker2 Created container frontend-app
Normal Started 16s kubelet, poc-worker2 Started container frontend-app
please find the below are the svc for deployment
root#jenkins-linux-vm:/home/admin# kubectl describe svc angular-service
Name: angular-service
Namespace: pre-release
Labels: <none>
Annotations: kubectl.kubernetes.io/last-applied-configuration:
{"apiVersion":"v1","kind":"Service","metadata":{"annotations":{},"name":"angular-service","namespace":"pre-release"},"spec":{"ports":[{"no...
Selector: app=frontend-app
Type: NodePort
IP: 10.96.227.143
Port: <unset> 80/TCP
TargetPort: 80/TCP
NodePort: <unset> 31000/TCP
Endpoints: 10.32.0.4:80,10.32.0.8:80
Session Affinity: None
External Traffic Policy: Cluster
Events: <none>
Please find the docker file here
FROM node:12.2.0
# set working directory
WORKDIR /app
# add `/app/node_modules/.bin` to $PATH
ENV PATH /app/node_modules/.bin:$PATH
# install and cache app dependencies
COPY package.json /app/package.json
# add app
COPY . /app
# start app
CMD ng serve --host 0.0.0.0
Can you please some one help me how to fix this issue

Answer 1

Here I could see the issue is with your Angular Dockerfile, you are using ng serve if you see your dependencies in package.json you will see "#angular/cli": "*" in order to have that inside your docker you need to add RUN npm install this will install all your dependencies inside your docker container, and you can do ng serve but ng serve is for development locally, it's not a good approach I would say.
To identify these kind of issues, it's advisable to run something like this on local machine in order to find if your docker container is working fine or not, before you could deploy it onto to k8s cluster, as you know kubernetes is a very big universe it will take time to identify the actual problem.
Ok coming to the issue (I can simply add a single command to your dockerfile and add my answer, but I wouldn't suggest that approach. So adding the complete answer which would look good), when you are deploying some frontend related application your docker image need to have the capabilities of serving the index.html page it's the end product after you build your Angular or React applications.
There are several ways this could be done. And there are several tutorials explaining the same, here is something I would suggest, your dockerfile should look like this. Adding comments what they do.
#Stage0: builder, based on Node alpine imagine to build and compile your angular code
FROM node:10-alpine as builder
WORKDIR /app
COPY package*.json /app/
# This is one thing you forgot in your dockerfile, if you add this it might work
RUN npm install
COPY . .
# This is normal build, it does ng build
RUN npm run build
#Stage 1, based on Nginx imagine, to have only the compile app inside nginx folders to serve
FROM nginx:1.15
COPY --from=builder /app/dist/ /usr/share/nginx/html
# This one copies the local nginx.conf file as default.conf for nginx to let it serve
COPY ./nginx.conf /etc/nginx/conf.d/default.conf
Please make sure you have nginx.conf file inside your code, file level is same as package.json
server {
listen 80;
sendfile on;
default_type application/octet-stream;
gzip on;
gzip_http_version 1.1;
gzip_disable "MSIE [1-6]\.";
gzip_min_length 1100;
gzip_vary on;
gzip_proxied expired no-cache no-store private auth;
gzip_types text/plain text/css application/json application/javascript application/x-javascript text/xml application/xml application/xml+rss text/javascript;
gzip_comp_level 9;
root /usr/share/nginx/html;
location / {
#try_files $uri $uri/ /index.html =404;
expires -1d;
alias /usr/share/nginx/html/;
try_files $uri$args $uri$args/ /index.html =404;
location ~* \.(?:ico|css|js|gif|jpe?g|png|svg|woff|woff2|ttf|eot)$ {
add_header Access-Control-Allow-Origin *;
}
}
}
Make sure you run docker run on local machine before you deploy it on to cluster.
Hope this helps.

Answer 2

If you are accessing the pod via nodeip:nodeport which will only work if you are accessing the pod from outside the cluster using a browser.
Here is a guide on how to expose an application via NodePort. In this case the nodes of your kubernetes cluster need to be accessible i.e should have public ip.
You should be using the cluster ip to access the pod from within the cluster i.e via exec from another pod as shown in below command.
kubectl exec -it angular-deployment-5d5fbf967c-zvzvl curl 10.96.16.68:80
I have a feeling that your docker container is not listening on port 80.