When we spin up a cluster with kubeadm in kubernetes, and the service's .yaml file looks like this :
apiVersion: v1
kind: Service
metadata:
name: neo4j
labels:
app: neo4j
component: core
spec:
clusterIP: None
ports:
- port: 7474
targetPort: 7474
name: browser
- port: 6362
targetPort: 6362
name: backup
selector:
app: neo4j
component: core
After all pods and services run, I do kubectl proxy and it says :
Starting to serve on 127.0.0.1:8001
So when I want to access to this service like :
curl localhost:8001/api/
it's just reachable inside the cluster! How can I reach to services outside the cluster?
You should expose your service using NodePort:
apiVersion: v1
kind: Service
metadata:
name: neo4j
labels:
app: neo4j
component: core
spec:
externalTrafficPolicy: Local
type: NodePort
ports:
- port: 7474
targetPort: 7474
name: browser
- port: 6362
targetPort: 6362
name: backup
selector:
app: neo4j
component: core
Now if you describe your service using
kubectl describe svc neo4j
You will get a nodeport value which will be in between 30000-32767 and you can access your service from outside the cluster using
curl http://<node_ip>:<node_port>
Hope this helps.
EDIT: Yes you can't directly use clusterIP: None in case of exposing service through NodePort. Now clusterIP: None means there is no internal load balancing done by kubernetes and for that we can also use externalTrafficPolicy=Local in service definition.
Alternatively, you might be able to use an ingress to route traffic to the correct Service.
Related
Trying to connect to one service from another in the same namespace. Using ClusterIP for creating the service. once the service is created use that Ip to access the service. Requests are successful sometimes and sometimes it is failing, I see both the pods are up and running. Below is the service configuration
apiVersion: v1 kind: Service metadata: name: serviceA spec: selector: app: ServiceA ports: - name: http port: 80 targetPort: 8080 type: ClusterIP
apiVersion: v1 kind: Service metadata: name: serviceB spec: selector: app: ServiceB ports: - name: http port: 80 targetPort: 8123 type: ClusterIP
Please use service name in invoking it as below
http://serviceA:80
K8s offers DNS for Services and Pods
Kubernetes creates DNS records for Services and Pods. You can contact Services with consistent DNS names instead of IP addresses.
I am following a very simple tutorial where it spawns a simple pod with an http endpoint and a service to expose that app using kubernetes.
The setup is very simple:
app-pod.yml
apiVersion: v1
kind: Pod
metadata:
name: hello-pod
labels:
app: web
spec:
containers:
- name: web-ctr
image: nigelpoulton/getting-started-k8s:1.0
ports:
- containerPort: 8080
And the nodeport service:
apiVersion: v1
kind: Service
metadata:
name: ps-nodeport
spec:
type: NodePort
ports:
- port: 80
targetPort: 8080
nodePort: 31111
protocol: TCP
selector:
app: web
The service and pod seem to be healthy:
But I can't reach the running app:
locahost:31111
Give " This site can't be reached message"
I am new to this stuff so any help will be appreciated.
In Kubernetes Kind cluster, by default, NodePort may not be bound to localhost. Please check the following resources:
https://kind.sigs.k8s.io/docs/user/quick-start/#mapping-ports-to-the-host-machine
How to use NodePort with kind?
The simplest way to access the service from localhost (like you are trying to do) would be to use
kubectl port-forward
e.g. the following command would work in your case - which forwards traffic from localhost -> ps-nodeport service
kubectl port-forward service/ps-nodeport 31111: 31111
I'm trying to achieve the following scenario:
My VM should be able to connect over a ClusterIP Service to the Pods behind it. The new beta feature here looks like this should be possible, but maybe I'm doing something wrong or misunderstood something...
The full documentation is here:
https://cloud.google.com/kubernetes-engine/docs/how-to/cloud-dns?hl=de#vpc_scope_dns
The DNS is working, I get a service IP, a route to the default network is available.
I can connect via pod IP. But it seems the service IP is not routable from outside the cluster. I know, that normally a ClusterIP is not available from outside the cluster. But then, I don't understand why this feature exists and it also does not match with the diagram provided in the docs. As this feature seems to provide cross-cluster/VM communication via services.
apiVersion: v1
kind: Service
metadata:
name: my-cip-service
namespace: default
spec:
ports:
- name: http
port: 80
protocol: TCP
targetPort: 8080
selector:
run: load-balancer-example
sessionAffinity: None
type: ClusterIP
Do I understand the feature wrong or am I missing a configuration?
Traffic Check:
This only works with headless Kubernetes services. So you'll need to modify your service spec to included clusterIP: None:
apiVersion: v1
kind: Service
metadata:
name: my-cip-service
namespace: default
spec:
clusterIP: None
ports:
- name: http
port: 80
protocol: TCP
targetPort: 8080
selector:
run: load-balancer-example
sessionAffinity: None
type: ClusterIP
I'm just new with Kubernetes, I'm using OpenStack and I would like to create a load balancer to access my NodeJs server running on 3 pods. I get a pending loop when my load balancer try to get its public ip. I'm using kubeadm with calico.
Screen: Pending External IP
This is a workaround method. You can mention the external IP:
apiVersion: v1
kind: Service
metadata:
name: node-js
labels:
name: node-js
spec:
type: LoadBalancer
externalIPs:
- 10.240.0.4
ports:
- port: 80
targetPort: 80
nodePort: 30000
selector:
name: node-js
I'm trying to expose my Deployment to a port which I can access through my local computer via Minikube.
I have tried two YAML configurations (one a load balancer, one just a service exposing a port).
I: http://pastebin.com/gL5ZBZg7
apiVersion: v1
kind: Service
metadata:
name: bot
labels:
app: bot
spec:
type: LoadBalancer
ports:
- port: 8000
targetPort: 8000
protocol: TCP
selector:
app: bot
II: http://pastebin.com/sSuyhzC5
apiVersion: v1
kind: Service
metadata:
name: bot
labels:
app: bot
spec:
ports:
- port: 8000
targetPort: 8000
protocol: TCP
selector:
app: bot
The deployment and the docker container image both expose port 8000, and the Pod is tagged with app:bot.
The first results in a service with a port which never finishes, and the external IP never gets assigned.
The second results in a port of bot:8000 TCP, bot:0 TCP in my dashboard and when I try "minikube service bot" nothing happens. The same happens if I type in "kubectl expose service bot".
I am on Mac OS X.
How can I set this up properly?
The LoadBalancer service is meant for Cloud providers and not really relevant for minikube.
From the documentation:
On cloud providers which support external load balancers, setting the type field to "LoadBalancer" will provision a load balancer for your Service.
Using a Service of type NodePort (see documentation) as mentioned in the Networking part of the minikube documentation is the intended way of exposing services on minikube.
So your configuration should look like this:
apiVersion: v1
kind: Service
metadata:
name: bot
labels:
app: bot
spec:
type: NodePort
ports:
- port: 8000
targetPort: 8000
nodePort: 30356
protocol: TCP
selector:
app: bot
And access your application through:
> IP=$(minikube ip)
> curl "http://$IP:30356"
Hope that helps.
Minikube now has the service command to access a service.
Use kubectl service <myservice>.
That will give you a URL which you can use to talk to the service.