Kubernetes: kube-dns Service Creation - service

After writing a skydns-svc.yml file with the IP 192.168.3.10 I recieve the following error:
Error: The Service "kube-dns" is invalid:spec.clusterIP: Invalid value: "192.168.3.10": provided IP is not in the valid range
skydns-svc.yml
apiVersion: v1
kind: Service
metadata:
name: kube-dns
namespace: kube-system
labels:
k8s-app: kube-dns
kubernetes.io/cluster-service: "true"
kubernetes.io/name: "KubeDNS"
spec:
selector:
k8s-app: kube-dns
clusterIP: 192.168.3.10
ports:
- name: dns
port: 53
protocol: UDP
- name: dns-tcp
port: 53
protocol: TCP
How is this not in a valid range and how could I go about resolving the error? Using V1.2

You need to set the clusterIP to an IP in the "SERVICE_CLUSTER_IP_RANGE", which is a CIDR range (typically a /16 or smaller) passed to the kube-apiserver process in the --service-cluster-ip-range flag. If you pick any address in that range you should no longer receive the above error.

Related

mentioned ip to endpoints are not getting configured in k8s

i am trying to add IPs manually using endpoint object in yaml. however minikube cluster is getting its defaults ips of endpoints instead of mention in the yaml file. why?
yamlfile:
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
labels:
app: nginx-app
spec:
replicas: 3
selector:
matchLabels:
app: nginx-app
template:
metadata:
labels:
app: nginx-app
spec:
containers:
- name: nginx-container
image: nginx:1.16
ports:
- containerPort: 80
---
apiVersion: v1
kind: Endpoints
metadata:
name: nginx-service
subsets:
- ports:
- port: 80
addresses:
- ip: 172.17.0.11 ---> configured ip
- ip: 172.17.0.12 ---> configured ip
- ip: 172.17.0.13 ---> configured ip
---
apiVersion: v1
kind: Service
metadata:
name: nginx-service
spec:
type: NodePort
selector:
app: nginx-app
ports:
- protocol: TCP
nodePort: 30464
port: 90
targetPort: 80
ips in endpoint output: (see 172.17.0.6, 172.17.0.7 and 172.17.0.8 while i have given 172.17.0.11, 172.17.0.12 and 172.17.0.13 in yaml)
/home/ravi/k8s>kubectl get endpoints
NAME ENDPOINTS AGE
kubernetes 192.168.49.2:8443 36h
nginx-service 172.17.0.6:80,172.17.0.7:80,172.17.0.8:80 5m59s
I have tried replicating your issue and got the configured IP addresses for endpoints.
The changes might have occurred due to the namespaces also, Once check it .

Bare-metal k8s ingress with nginx-ingress

I can't apply an ingress configuration.
I need access a jupyter-lab service by it's DNS
http://jupyter-lab.local
It's deployed to a 3 node bare metal k8s cluster
node1.local (master)
node2.local (worker)
node3.local (worker)
Flannel is installed as the Network controller
I've installed nginx ingress for bare metal like this
kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v0.44.0/deploy/static/provider/baremetal/deploy.yaml
When deployed the jupyter-lab pod is on node2 and the NodePort service responds correctly from http://node2.local:30004 (see below)
I'm expecting that the ingress-nginx controller will expose the ClusterIP service by its DNS name ...... thats what I need, is that wrong?
This is the CIP service, defined with symmetrical ports 8888 to be as simple as possible (is that wrong?)
---
apiVersion: v1
kind: Service
metadata:
name: jupyter-lab-cip
namespace: default
spec:
type: ClusterIP
ports:
- port: 8888
targetPort: 8888
selector:
app: jupyter-lab
The DNS name jupyter-lab.local resolves to the ip address range of the cluster, but times out with no response. Failed to connect to jupyter-lab.local port 80: No route to host
firewall-cmd --list-all shows that port 80 is open on each node
This is the ingress definition for http into the cluster (any node) on port 80. (is that wrong ?)
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: jupyter-lab-ingress
annotations:
# nginx.ingress.kubernetes.io/rewrite-target: /
nginx.ingress.kubernetes.io: /
spec:
rules:
- host: jupyter-lab.local
http:
paths:
- path: /
pathType: Prefix
backend:
service:
name: jupyter-lab-cip
port:
number: 80
This the deployment
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: jupyter-lab-dpt
namespace: default
spec:
replicas: 1
selector:
matchLabels:
app: jupyter-lab
template:
metadata:
labels:
app: jupyter-lab
spec:
volumes:
- name: jupyter-lab-home
persistentVolumeClaim:
claimName: jupyter-lab-pvc
containers:
- name: jupyter-lab
image: docker.io/jupyter/tensorflow-notebook
ports:
- containerPort: 8888
volumeMounts:
- name: jupyter-lab-home
mountPath: /var/jupyter-lab_home
env:
- name: "JUPYTER_ENABLE_LAB"
value: "yes"
I can successfully access jupyter-lab by its NodePort http://node2:30004 with this definition:
---
apiVersion: v1
kind: Service
metadata:
name: jupyter-lab-nodeport
namespace: default
spec:
type: NodePort
ports:
- port: 10003
targetPort: 8888
nodePort: 30004
selector:
app: jupyter-lab
How can I get ingress to my jupyter-lab at http://jupyter-lab.local ???
the command kubectl get endpoints -n ingress-nginx ingress-nginx-controller-admission returns :
ingress-nginx-controller-admission 10.244.2.4:8443 15m
Am I misconfiguring ports ?
Are my "selector:appname" definitions wrong ?
Am I missing a part
How can I debug what's going on ?
Other details
I was getting this error when applying an ingress kubectl apply -f default-ingress.yml
Error from server (InternalError): error when creating "minnimal-ingress.yml": Internal error occurred: failed calling webhook "validate.nginx.ingress.kubernetes.io": Post "https://ingress-nginx-contr
oller-admission.ingress-nginx.svc:443/networking/v1beta1/ingresses?timeout=10s": context deadline exceeded
This command kubectl delete validatingwebhookconfigurations --all-namespaces
removed the validating webhook ... was that wrong to do?
I've opened port 8443 on each node in the cluster
Ingress is invalid, try the following:
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: jupyter-lab-ingress
annotations:
nginx.ingress.kubernetes.io/rewrite-target: /
spec:
rules:
- host: jupyter-lab.local
http: # <- removed the -
paths:
- path: /
pathType: Prefix
backend:
service:
# name: jupyter-lab-cip
name: jupyter-lab-nodeport
port:
number: 8888
---
apiVersion: v1
kind: Service
metadata:
name: jupyter-lab-cip
namespace: default
spec:
type: ClusterIP
ports:
- port: 8888
targetPort: 8888
selector:
app: jupyter-lab
If I understand correctly, you are trying to expose jupyternb through ingress nginx proxy and to make it accessible through port 80.
Run the folllowing command to check what nodeport is used by nginx ingress service:
$ kubectl get svc -n ingress-nginx ingress-nginx-controller
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
ingress-nginx-controller NodePort 10.96.240.73 <none> 80:30816/TCP,443:31475/TCP 3h30m
In my case that is port 30816 (for http) and 31475 (for https).
Using NodePort type you can only use ports in range 30000-32767 (k8s docs: https://kubernetes.io/docs/concepts/services-networking/service/#nodeport). You can change it using kube-apiserver flag --service-node-port-range and then set it to e.g. 80-32767 and then in your ingress-nginx-controller service set nodePort: 80
apiVersion: v1
kind: Service
metadata:
annotations: {}
labels:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/managed-by: Helm
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/version: 0.44.0
helm.sh/chart: ingress-nginx-3.23.0
name: ingress-nginx-controller
namespace: ingress-nginx
spec:
ports:
- name: http
port: 80
protocol: TCP
targetPort: http
nodePort: 80 # <- HERE
- name: https
port: 443
protocol: TCP
targetPort: https
nodePort: 443 # <- HERE
selector:
app.kubernetes.io/component: controller
app.kubernetes.io/instance: ingress-nginx
app.kubernetes.io/name: ingress-nginx
type: NodePort
Although this is genereally not advised to change service-node-port-range since you may encounter some issues if you use ports that are already open on nodes (e.g. port 10250 that is opened by kubelet on every node).
What might be a better solution is to use MetalLB.
EDIT:
How can I get ingress to my jupyter-lab at http://jupyter-lab.local ???
Assuming you don't need a failure tolerant solution, download the https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v0.44.0/deploy/static/provider/baremetal/deploy.yaml file and change ports: section for the deployment object like following:
ports:
- name: http
containerPort: 80
hostPort: 80 # <- add this line
protocol: TCP
- name: https
containerPort: 443
hostPort: 443 # <- add this line
protocol: TCP
- name: webhook
containerPort: 8443
protocol: TCP
and apply the changes:
kubectl apply -f deploy.yaml
Now run:
$ kubectl get po -n ingress-nginx ingress-nginx-controller-<HERE PLACE YOUR HASH> -owide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
ingress-nginx-controller-67897c9494-c7dwj 1/1 Running 0 97s 172.17.0.6 <node_name> <none> <none>
Notice the <node_name> in NODE column. This is a node's name where the pod got scheduled. Now take this nodes IP and add it to your /etc/hosts file.
It should work now (go to http://jupyter-lab.local to check it), but this solution is fragile and if nginx ingress controller pod gets rescheduled to other node it will stop working (and it will stay lik this until you change the ip in /etc/hosts file). It's also generally not advised to use hostPort: field unless you have a very good reason to do so, so don't abuse it.
If you need failure tolerant solution, use MetalLB and create a service of type LoadBalancer for nginx ingress controller.
I haven't tested it but the following should do the job, assuming that you correctly configured MetalLB:
kubectl delete svc -n ingress-nginx ingress-nginx-controller
kubectl expose deployment -n ingress-nginx ingress-nginx-controller --type LoadBalancer

Though external ip is resolved, the website returns connection timedout in kubernetes GKE

I have created a k8s deployment and service yaml for a static website. External IP address is also resolved in kubernetes service. But when I try to access the website through curl or browser, it returns connection timed out.
Dockerfile:
FROM nginx:alpine
COPY . /usr/share/nginx/html
K8s deployment yml:
apiVersion: apps/v1
kind: Deployment
metadata:
name: ohno-website
labels:
app: ohno-website
spec:
replicas: 1
selector:
matchLabels:
app: ohno-website
template:
metadata:
labels:
app: ohno-website
spec:
containers:
- name: ohno-website
image: gkganeshr/ohno-website:v0.1
imagePullPolicy: Always
ports:
- containerPort: 80
k8s service yml:
apiVersion: v1
kind: Service
metadata:
name: ohno-website
spec:
type: LoadBalancer
ports:
- protocol: TCP
port: 80
targetPort: 9376
selector:
app: ohno-website
ohno_fooserver#cloudshell:~ (fourth-webbing-279817)$ kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.16.0.1 <none> 443/TCP 8h
ohno-website LoadBalancer 10.16.12.162 34.70.213.174 80:31977/TCP 7h4m
The target port defined in the service defition YAML is incorrect. It should match with container port from pod definition in deployment YAML
targetPort: 9376
should be changed to
targetPort: 80

Kubernetes deployment not publicly accesible

im trying to access a deloyment on our Kubernetes cluster on Azure. This is a Azure Kubernetes Service (AKS). Here are the configuration files for the deployment and the service that should expose the deployment.
Configurations
apiVersion: apps/v1
kind: Deployment
metadata:
name: mira-api-deployment
spec:
replicas: 1
selector:
matchLabels:
app: mira-api
template:
metadata:
labels:
app: mira-api
spec:
containers:
- name: backend
image: registry.gitlab.com/izit/mira-backend
ports:
- containerPort: 8080
name: http
protocol: TCP
imagePullSecrets:
- name: regcred
apiVersion: v1
kind: Service
metadata:
name: mira-api-service
spec:
type: LoadBalancer
ports:
- port: 80
targetPort: 8080
protocol: TCP
name: http
selector:
run: mira-api
When I check the cluster after applying these configurations I, I see the pod running correctly. Also the service is created and has public IP assigned.
After this deployment I don't see any requests getting handled. I get a error message in my browser saying the site is inaccessible. Any ideas what I could have configured wrong?
Your service selector labels and pod labels do not match.
You have app: mira-api label in deployment's pod template but have run: mira-api in service's label selector.
Change your service selector label to match the pod label as follows.
apiVersion: v1
kind: Service
metadata:
name: mira-api-service
spec:
type: LoadBalancer
ports:
- port: 80
targetPort: 8080
protocol: TCP
name: http
selector:
app: mira-api
To make sure your service is selecting the backend pods or not, you can run kubectl describe svc <svc name> command and check if it has any Endpoints listed.
# kubectl describe svc postgres
Name: postgres
Namespace: default
Labels: app=postgres
Annotations: kubectl.kubernetes.io/last-applied-configuration:
{"apiVersion":"v1","kind":"Service","metadata":{"annotations":{},"labels":{"app":"postgres"},"name":"postgres","namespace":"default"},"s...
Selector: app=postgres
Type: ClusterIP
IP: 10.106.7.183
Port: default 5432/TCP
TargetPort: 5432/TCP
Endpoints: 10.244.2.117:5432 <------- This line
Session Affinity: None
Events: <none>

Kubernetes Dashboard behind AWS ELB or internal LB

I have deployed K8s dashboard via
kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/master/src/deploy/recommended/kubernetes-dashboard.yaml.
And I can connect to the dashboard by running kubectl proxy.
My question is how can I expose this dashboard via internal LB or ELB?
I have changed the kubernetes-dashboard service
kind: Service
apiVersion: v1
metadata:
labels:
k8s-app: kubernetes-dashboard
name: kubernetes-dashboard
namespace: kube-system
annotations:
# service.beta.kubernetes.io/aws-load-balancer-internal: 0.0.0.0/0
service.beta.kubernetes.io/aws-load-balancer-backend-protocol: http
spec:
type: LoadBalancer
# loadBalancerSourceRanges:
# - x.x.x.x/32
ports:
- port: 80
targetPort: 8443
protocol: TCP
selector:
k8s-app: kubernetes-dashboard
Then I hit the ELB DNS record and nothing return (eg - xxxxxxxxxxx.us-east-1.elb.amazonaws.com).
Anyone know how to fix this issue?
note - This is a POC cluster and I don't have any issue with security concern at the moment.
Thank you
kind: Service
apiVersion: v1
metadata:
labels:
k8s-app: kubernetes-dashboard
name: kubernetes-dashboard
namespace: kube-system
annotations:
service.beta.kubernetes.io/aws-load-balancer-internal: 0.0.0.0/0
spec:
type: LoadBalancer
ports:
- port: 443
protocol: TCP
targetPort: 8443
selector:
k8s-app: kubernetes-dashboard
And https://<internal-lb-dns-record> should work.