Getting an Kubernetes Ingress endpoint/IP address - kubernetes

Question

Base OS : CentOS (1 master 2 minions)
K8S version : 1.9.5 (deployed using KubeSpray)
I am new to Kubernetes Ingress and am setting up 2 different services, each reachable with its own path.
I have created 2 deployments :
kubectl run nginx --image=nginx --port=80
kubectl run echoserver --image=gcr.io/google_containers/echoserver:1.4 --port=8080
I have also created their corresponding services :
kubectl expose deployment nginx --target-port=80 --type=NodePort
kubectl expose deployment echoserver --target-port=8080 --type=NodePort
My svc are :
[root#node1 kubernetes]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
echoserver NodePort 10.233.48.121 <none> 8080:31250/TCP 47m
nginx NodePort 10.233.44.54 <none> 80:32018/TCP 1h
My NodeIP address is 172.16.16.2 and I can access both pods using
http://172.16.16.2:31250 &
http://172.16.16.2:32018
Now on top of this I want to deploy an Ingress so that I can reach both pods not using 2 IPs and 2 different ports BUT 1 IP address with different paths.
So my Ingress file is :
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: fanout-nginx-ingress
spec:
rules:
- http:
paths:
- path: /nginx
backend:
serviceName: nginx
servicePort: 80
- path: /echo
backend:
serviceName: echoserver
servicePort: 8080
This yields :
[root#node1 kubernetes]# kubectl describe ing fanout-nginx-ingress
Name: fanout-nginx-ingress
Namespace: development
Address:
Default backend: default-http-backend:80 (<none>)
Rules:
Host Path Backends
---- ---- --------
*
/nginx nginx:80 (<none>)
/echo echoserver:8080 (<none>)
Annotations:
Events: <none>
Now when I try accessing the Pods using the NodeIP address (172.16.16.2), I get nothing.
http://172.16.16.2/echo
http://172.16.16.2/nginx
Is there something I have missed in my configs ?

Answer 1

I had the same issue on my bare metal installation - or rather something close to that (kubernetes virtual cluster - set of virtual machines connected via Host-Only-Adapter). Here is link to my kubernetes vlab.
First of all make sure that you have ingress controller installed. Currently there are two ingress controller worth trying kubernetes nginx ingress controller and nginx kubernetes ingress controller -I installed first one.
Installation
Go to installation instructions and execute first step
# prerequisite-generic-deployment-command
$ kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/mandatory.yaml
Next get IP addresses of cluster nodes.
$ kubectl get nodes -o wide
NAME STATUS ROLES ... INTERNAL-IP
master Ready master ... 192.168.121.110
node01 Ready <none> ... 192.168.121.111
node02 Ready <none> ... 192.168.121.112
Further, crate ingress-nginx service of type LoadBalancer. I do it by downloading NodePort template service from installation tutorial and making following adjustments in svc-ingress-nginx-lb.yaml file.
$ curl https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/provider/baremetal/service-nodeport.yaml > svc-ingress-nginx-lb.yaml
# my changes svc-ingress-nginx-lb.yaml
type: LoadBalancer
externalIPs:
- 192.168.121.110
- 192.168.121.111
- 192.168.121.112
externalTrafficPolicy: Local
# create ingress- service
$ kubectl apply -f svc-ingress-nginx-lb.yaml
Verification
Check that ingress-nginx service was created.
$ kubectl get svc -n ingress-nginx
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
ingress-nginx LoadBalancer 10.110.127.9 192.168.121.110,192.168.121.111,192.168.121.112 80:30284/TCP,443:31684/TCP 70m
Check that nginx-ingress-controller deployment was created.
$ kubectl get deploy -n ingress-nginx
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
nginx-ingress-controller 1 1 1 1 73m
Check that nginx-ingress pod is running.
$ kubectl get pods --all-namespaces -l
app.kubernetes.io/name=ingress-nginx
NAMESPACE NAME READY STATUS RESTARTS AGE
ingress-nginx nginx-ingress-controller-5cd796c58c-lg6d4 1/1 Running 0 75m
Finally, check ingress controller version. Don't forget to change pod name!
$ kubectl exec -it nginx-ingress-controller-5cd796c58c-lg6d4 -n ingress-nginx -- /nginx-ingress-controller --version
-------------------------------------------------------------------------------
NGINX Ingress controller
Release: 0.21.0
Build: git-b65b85cd9
Repository: https://github.com/aledbf/ingress-nginx
-------------------------------------------------------------------------------
Testing
Test that ingress controller is working by executing steps in this tutorial -of course, you will omit minikube part.
Successful, execution of all steps will create ingress controler resource that should look like this.
$ kubectl get ing
NAME HOSTS ADDRESS PORTS AGE
ingress-tutorial myminikube.info,cheeses.all 192.168.121.110,192.168.121.111,192.168.121.112 80 91m
And pods that looks like this.
$ kubectl get pods
NAME READY STATUS RESTARTS AGE
cheddar-cheese-6f94c9dbfd-cll4z 1/1 Running 0 110m
echoserver-55dcfbf8c6-dwl6s 1/1 Running 0 104m
stilton-cheese-5f6bbdd7dd-8s8bf 1/1 Running 0 110m
Finally, test that request to myminikube.info propagates via ingress load balancer.
$ curl myminikube.info
CLIENT VALUES:
client_address=10.44.0.7
command=GET
real path=/
query=nil
request_version=1.1
request_uri=http://myminikube.info:8080/
SERVER VALUES:
server_version=nginx: 1.10.0 - lua: 10001
HEADERS RECEIVED:
accept=*/*
host=myminikube.info
user-agent=curl/7.29.0
x-forwarded-for=10.32.0.1
x-forwarded-host=myminikube.info
x-forwarded-port=80
x-forwarded-proto=http
x-original-uri=/
x-real-ip=10.32.0.1
x-request-id=b2fb3ee219507bfa12472c7d481d4b72
x-scheme=http
BODY:
It was a long journey to make ingress working on bear metal like environment.Thus, i will include relevant links that helped me along.
reproducable tutorial
installation of minikube on ubuntu
ingress I
ingress II
digging
reverse engineering on ingress in kubernetes

Answer 2

Check if you have an ingress controller in your cluster:
$ kubectl get po --all-namespaces
You should see something like:
kube-system nginx-ingress-controller-gwts0 1/1 Running 0 18d
It's only possible to create an ingress to address services inside the namespace in which the Ingress resides.
Cross-namespace ingresses are not implemented for security reasons.

Answer 3

It seems that your cluster is missing Ingress controller.
In general, Ingress controller works as follows:
1. search for a certain type of objects (ingress,"nginx") in a cluster
2. parse that object and create configuration section for a specific ingress pod.
3. update that pod object (restart it with updated configuration)
That particular pod is responsible for processing traffic from incoming ports (usually a couple of dedicated ports on nodes) to configured traffic destination in cluster.
You can choose from two supported and maintained controllers - Nginx and GCE
The ingress controller consists of several components that you create during installation.
Here is installation part from Nginx Ingress documentation:
curl https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/namespace.yaml | kubectl apply -f -
curl https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/default-backend.yaml | kubectl apply -f -
curl https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/configmap.yaml | kubectl apply -f -
curl https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/tcp-services-configmap.yaml | kubectl apply -f -
curl https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/udp-services-configmap.yaml | kubectl apply -f -
If you have RBAC authorization configured in your cluster:
curl https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/rbac.yaml | kubectl apply -f -
curl https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/with-rbac.yaml | kubectl apply -f -
If no RBAC configured:
curl https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/without-rbac.yaml | kubectl apply -f -
In case you create cluster from scratch:
curl https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/provider/baremetal/service-nodeport.yaml | kubectl apply -f -
Verify your installation:
kubectl get pods --all-namespaces -l app=ingress-nginx --watch
You should see something like:
NAMESPACE NAME READY STATUS RESTARTS AGE
ingress-nginx nginx-ingress-controller-699cdf846-nj2rw 1/1 Running 0 1h
Check available services and their parameters:
kubectl get services --all-namespaces
If you are using custom service provider deployment (minikube, AWS, Azure, GKE), follow Nginx Ingress documentation for installation details.
See official Kubernetes Ingress documentation for details about Ingress.

Answer 4

I was using microk8s default nginx ingress controller on a later version of k8s (> 1.18) and I noticed this specific annotation was causing me an issue:
kubernetes.io/ingress.class: "nginx"
It's present in a lot of older documentation and examples but it's apparently deprecated (see https://kubernetes.io/docs/concepts/services-networking/ingress/) and I had also defined an ingressClassName of "public" using the newer annotation. I'm not sure if it was the conflict between the two that caused the issue but once I removed the deprecated annotation my address appeared.

Answer 5

For working your ingress resources (fanout-nginx-ingress), you need to first deploy the ingress controller which is by-default not come in your local kubernetes cluster. You need to deploy it yourself.
There are many solution out there and you can use any of them, but nginx ingress controller is fine.
For detail information you can refer a great video on ingress by Mumshad Mannambeth here:
https://www.youtube.com/watch?v=GhZi4DxaxxE