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
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 have a running pod that was created with the following pod-definition.yaml:
apiVersion: v1
kind: Pod
metadata:
name: microservice-one-pod-name
labels:
app: microservice-one-app-label
type: front-end
spec:
containers:
- name: microservice-one
image: vismarkjuarez1994/microserviceone
ports:
- containerPort: 2019
I then created a Service using the following service-definition.yaml:
kind: Service
apiVersion: v1
metadata:
name: microserviceone-service
spec:
ports:
- port: 30008
targetPort: 2019
protocol: TCP
selector:
app: microservice-one-app-label
type: NodePort
I then ran kubectl describe node minikube to find the Node IP I should be connecting to -- which yielded:
Addresses:
InternalIP: 192.168.49.2
Hostname: minikube
But I get no response when I run the following curl command:
curl 192.168.49.2:30008
The request also times out when I try to access 192.168.49.2:30008 from a browser.
The pod logs show that the container is up and running. Why can't I access my Service?
The problem is that you are trying to access your service at the port parameter which is the internal port at which the service will be exposed, even when using NodePort type.
The parameter you were searching is called nodePort, which can optionally be specified together with port and targetPort. Quoting the documentation:
By default and for convenience, the Kubernetes control plane will
allocate a port from a range (default: 30000-32767)
Since you didn't specify the nodePort, one in the range was automatically picked up. You can check which one by:
kubectl get svc -owide
And then access your service externally at that port.
As an alternative, you can change your service definition to be something like:
kind: Service
apiVersion: v1
metadata:
name: microserviceone-service
spec:
ports:
- port: 30008
targetPort: 2019
nodePort: 30008
protocol: TCP
selector:
app: microservice-one-app-label
type: NodePort
But take in mind that you may need to delete your service and create it again in order to change the nodePort allocated.
I think you missed the Port in your service:
apiVersion: v1
kind: Pod
metadata:
name: microservice-one-pod-name
labels:
app: microservice-one-app-label
type: front-end
spec:
containers:
- name: microservice-one
image: vismarkjuarez1994/microserviceone
ports:
- containerPort: 2019
and your service should be like this:
kind: Service
apiVersion: v1
metadata:
name: microserviceone-service
spec:
ports:
- port: 2019
targetPort: 2019
nodePort: 30008
protocol: TCP
selector:
app: microservice-one-app-label
type: NodePort
You can access to your app after enabling the Minikube ingress if you want trying Ingress with Minikube.
minikube addons enable ingress
I have deployed RabbitMQ in Kubernetes using a service with the load balancer type. When creating a service, an external IP is created. Could you please tell me if I can bind another deployment to this IP with other ports? Thanks.
It is possible, you just have to create a service with multiple ports, for example:
apiVersion: v1
kind: Service
metadata:
name: service-name
spec:
ports:
- name: http
port: 80
targetPort: 80
- name: https
port: 443
targetPort: 443
- name: any other port
port: <port-number>
targetPort: <target-port>
selector:
app: app
type: LoadBalancer
And you will output similar to this:
$kubectl get svc
service-name LoadBalancer <Internal-IP> <External-IP> 80:30870/TCP,443:32602/TCP,<other-port>:32388/TCP
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.
I installed kubernetes cluster on my 3 virtualbox vms. 3 vms all run Ubuntu14.04 with ufw disabled. Kubernetes versin is 1.6. Here is my config files for creating pod and service.
Pod pod.yaml:
apiVersion: v1
kind: ReplicationController
metadata:
name: frontend
labels:
name: frontend
spec:
replicas: 3
selector:
name: frontend
template:
metadata:
labels:
name: frontend
spec:
imagePullSecrets:
- name: regsecret
containers:
- name: frontend
image: hub.allinmoney.com/kubeguide/guestbook-php-frontend
env:
- name: GET_HOSTS_FROM
value: env
ports:
- containerPort: 80
Service service.yaml:
apiVersion: v1
kind: Service
metadata:
name: frontend
labels:
name: frontend
spec:
type: NodePort
ports:
- port: 80
targetPort: 31000
nodePort: 31000
selector:
name: frontend
I create service with type NodePort. When I run command kubectl create -f service.yaml, it outputs like below and I can't find the exposed port 31000 in any kube nodes:
You have exposed your service on an external port on all nodes in your
cluster. If you want to expose this service to the external internet, you may
need to set up firewall rules for the service port(s) (tcp:31000) to serve traffic.
See http://releases.k8s.io/release-1.3/docs/user-guide/services-firewalls.md for more details.
Could anyone tell how to solve this or give me any tips?
As it says in the error message you need to set up firewall rules for your nodes to accept traffic on the node ports (default: 30000-32767).
Firewall rule example
Name: [firewall-rule-name]
Targets: [node-target-name, node-target2-name]
Source filters: IP ranges: 0.0.0.0/0
Protocols / ports: tcp:80,443,30000-32767
Action: Allow
Priority: 1000
Network: default
Your targetPort is also incorrect it needs to point to the corresponding port in the Pod (Port 80).