Error 404 after deploying and exposing Nginx pod - nginx

Question

I have deployed and exposed Nginx with the following commands:
sudo kubectl create deployment mynginx1 --image=nginx
sudo kubectl expose deployment mynginx1 --type NodePort --port 8080
I access using http://<master node IP>:<port> or http://172.17.135.42:31788
But I am getting Error 404. Help appreciated.
gtan#master:~$ kubectl get pods -owide -A
NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
default mynginx1-f544c49cb-g92w2 1/1 Running 0 3m19s 172.168.10.2 slave1 <none> <none>
kube-system coredns-66bff467f8-92r4n 1/1 Running 0 7m56s 172.168.10.2 master <none> <none>
kube-system coredns-66bff467f8-gc7tc 1/1 Running 0 7m56s 172.168.10.3 master <none> <none>
kube-system etcd-master 1/1 Running 0 8m6s 172.17.82.100 master <none> <none>
kube-system kube-apiserver-master 1/1 Running 0 8m6s 172.17.82.100 master <none> <none>
kube-system kube-controller-manager-master 1/1 Running 0 8m6s 172.17.82.100 master <none> <none>
kube-system kube-flannel-ds-amd64-24pwc 1/1 Running 3 4m58s 172.17.82.110 slave1 <none> <none>
kube-system kube-flannel-ds-amd64-q5qwg 1/1 Running 0 5m28s 172.17.82.100 master <none> <none>
kube-system kube-proxy-hf59b 1/1 Running 0 4m58s 172.17.82.110 slave1 <none> <none>
kube-system kube-proxy-r7pz6 1/1 Running 0 7m56s 172.17.82.100 master <none> <none>
kube-system kube-scheduler-master 1/1 Running 0 8m5s 172.17.82.100 master <none> <none>
gtan#master:~$
gtan#master:~$ curl -IL http://172.17.82.100:30131
curl: (7) Failed to connect to 172.17.82.100 port 30131: Connection refused where "172.17.82.100" is the master node ip address.
gtan#master:~$ kubectl get services -o wide -A
NAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
default kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 15m <none>
default mynginx1 NodePort 10.102.106.240 <none> 80:30131/TCP 10m app=mynginx1
kube-system kube-dns ClusterIP 10.96.0.10 <none> 53/UDP,53/TCP,9153/TCP 15m k8s-app=kube-dns

Answer 1

What is the architecture of your setup? do you have worker node and master node on same machine?
check the nginx pod status with :
kubectl get pods
If the pod is running without issue then hit your worker machine IP with NodePort http:/Workernode_IP:Nodeport

Answer 2

The default nginx container port is 80 as you can see here. Just change the container port from 8080 to 80 in your second command:
sudo kubectl expose deployment mynginx1 --type NodePort --port 80
and try to reach the service using the NodePort showed in the output of the command, for example:
$kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
mynginx1 NodePort 10.97.142.170 <none> 80:31591/TCP 8m9s
Altenatively, you can use this yaml spec to configure your pod and service:
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx
spec:
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx
ports:
- name: http
containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
name: nginx-svc
spec:
selector:
app: nginx
ports:
- protocol: TCP
port: 80
targetPort: 80
type: NodePort
Testing using curl:
$ curl -IL http://localhost:31591
HTTP/1.1 200 OK
Server: nginx/1.17.10
Date: Tue, 12 May 2020 10:05:04 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 14 Apr 2020 14:19:26 GMT
Connection: keep-alive
ETag: "5e95c66e-264"
Accept-Ranges: bytes
Also, I recommend you to reserve a time to take a look in these documentations pages:
Kuberentes Concepts
Services