I have deployed my app on the limited available Kubernetes cluster on DigitalOcean.
I have a spring boot app with a service exposed on port 31744 for external using nodeport service config.
I created a Loadbalancer using the yaml config per DO link doc: https://www.digitalocean.com/docs/kubernetes/how-to/add-load-balancer/
However, I am not able to hook up to my service. Can you advise on how it can be done so I can access my service from the loadbalancer?
The following is my "kubectl get svc" output for my app service:
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
my-springboot NodePort 10.245.6.216 <none> 8080:31744/TCP 2d18h
kubernetes ClusterIP 10.245.0.1 <none> 443/TCP 3d20h
sample-load-balancer LoadBalancer 10.245.53.168 58.183.251.550 80:30495/TCP 2m6s
The following is my loadbalancer.yaml:
apiVersion: v1
kind: Service
metadata:
name: sample-load-balancer
spec:
type: LoadBalancer
ports:
- protocol: TCP
port: 80
targetPort: 31744
name: http
My service.yaml:
apiVersion: v1
kind: Service
metadata:
name: my-springboot
labels:
app: my-springboot
tier: backend
spec:
type: NodePort
ports:
# the port that this service should serve on
- port: 8080
selector:
app: my-springboot
tier: backend
Thanks
To expose your service using LoadBalancer instead of NodePort you need to provide type in service as LoadBalancer. So your new service config yaml will be:
apiVersion: v1
kind: Service
metadata:
name: my-springboot
labels:
app: my-springboot
tier: backend
spec:
type: LoadBalancer
ports:
# the port that this service should serve on
- port: 8080
selector:
app: my-springboot
tier: backend
Once you apply the above service yaml file, you will get the external IP in kubectl get svc which can be used to access the service from outside the kubernetes cluster.
Related
I have a simple ASP.NET core Web API. It works locally. I deployed it in Azure AKS using the following yaml:
apiVersion: apps/v1
kind: Deployment
metadata:
name: sa-be
spec:
selector:
matchLabels:
name: sa-be
template:
metadata:
labels:
name: sa-be
spec:
nodeSelector:
kubernetes.io/os: linux
containers:
- name: sa-be
image: francotiveron/anapi:latest
resources:
limits:
memory: "64Mi"
cpu: "250m"
---
apiVersion: v1
kind: Service
metadata:
name: sa-be-s
spec:
type: LoadBalancer
selector:
name: sa-be
ports:
- port: 8080
targetPort: 80
The result is:
> kubectl get service sa-be-s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
sa-be-s LoadBalancer 10.0.157.200 20.53.188.247 8080:32533/TCP 4h55m
> kubectl describe service sa-be-s
Name: sa-be-s
Namespace: default
Labels: <none>
Annotations: <none>
Selector: name=sa-be
Type: LoadBalancer
IP Families: <none>
IP: 10.0.157.200
IPs: <none>
LoadBalancer Ingress: 20.53.188.247
Port: <unset> 8080/TCP
TargetPort: 80/TCP
NodePort: <unset> 32533/TCP
Endpoints: 10.244.2.5:80
Session Affinity: None
External Traffic Policy: Cluster
Events: <none>
I expected to reach the Web API at http://20.53.188.247:32533/, instead it is reachable only at http://20.53.188.247:8080/
Can someone explain
Is this is he expected behaviour
If yes, what is the use of the NodePort (32533)?
Yes, expected.
Explained: Kubernetes Service Ports - please read full article to understand what is going on in the background.
Loadbalancer part:
apiVersion: v1
kind: Service
metadata:
name: sa-be-s
spec:
type: LoadBalancer
selector:
name: sa-be
ports:
- port: 8080
targetPort: 80
port is the port the cloud load balancer will listen on (8080 in our
example) and targetPort is the port the application is listening on in
the Pods/containers. Kubernetes works with your cloud’s APIs to create
a load balancer and everything needed to get traffic hitting the load
balancer on port 8080 all the way back to the Pods/containers in your
cluster listening on targetPort 80.
now main:
Behind the scenes, many implementations create NodePorts to glue the cloud load balancer to the cluster. The traffic flow is usually like this.
I have an application running inside minikube K8 cluster. It’s a simple REST endpoint. The issue is after deployment I am unable to access that application from my local computer.
Using http://{node ip}:{node port} endpoint.
However, if I do:
kubectl port-forward (actual pod name) 8000:8000
The application becomes accessible at: 127.0.0.1:8000 from my local desktop.
Is this the right way?
I believe this isn't the right way? as I am directly forwarding my traffic to the pod and this port forwarding won't remain once this pod is deleted.
What am I missing here and what is the right way to resolve this?
I have also configured a NodePort service, which should handle this but I am afraid it doesn’t seem to be working:
apiVersion: v1
kind: Service
metadata:
labels:
app: rest-api
name: rest-api-np
namespace: rest-api-namespace
spec:
type: NodePort
ports:
- port: 8000
selector:
app: rest-api
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: rest-api
name: rest-api-deployment
namespace: rest-api-namespace
spec:
replicas: 1
selector:
matchLabels:
app: rest-api
strategy: {}
template:
metadata:
creationTimestamp: null
labels:
app: rest-api
spec:
containers:
- image: oneImage:latest
name: rest-api
You are having issues because your service is placed in default namespace while your deployment is in rest-api-namespace namespace.
I have deploy you yaml files and when the describe the service there were no endpoints:
➜ k describe svc rest-api-np
Name: rest-api-np
Namespace: default
Labels: app=rest-api
Annotations: <none>
Selector: app=rest-api
Type: NodePort
IP: 10.100.111.228
Port: <unset> 8000/TCP
TargetPort: 8000/TCP
NodePort: <unset> 31668/TCP
Endpoints: <none>
Session Affinity: None
External Traffic Policy: Cluster
Events: <none>
Solution for that is to create service in the the same namespace. Once you do that, an ip address and port will appear in the Endpoints field:
➜ k describe svc -n rest-api-namespace rest-api-np
Name: rest-api-np
Namespace: rest-api-namespace
Labels: app=rest-api
Annotations: <none>
Selector: app=rest-api
Type: NodePort
IP: 10.99.49.24
Port: <unset> 8000/TCP
TargetPort: 8000/TCP
NodePort: <unset> 32116/TCP
Endpoints: 172.18.0.3:8000
Session Affinity: None
External Traffic Policy: Cluster
Events: <none>
Alternative way is to add endpoints manually:
apiVersion: v1
kind: Endpoints
metadata:
name: my-service # please note that endpoints and service needs to have the same name
subsets:
- addresses:
- ip: 192.0.2.42 #ip of the pod
ports:
- port: 8000
Since you can do port forwarding the rest api service properly connected to your deployment. In that case the service can be resolved using the following way.
First find out the minikube ip
minikube ip
Then the node port of your service like
kubectl get service rest-api-np
Once you have these two details just do http://(minikube-ip):(node-port)
I have a service and deployment kube config files like below.
Now, when i apply these two files, its creating a loadbalancer but its targeting to a random port but not port 80.
I'm a newbie to EKS and tried different kube config files but it still tries to target a random port.
service file:
apiVersion: v1
kind: Service
metadata:
name: runners-test
labels:
app: runners-test
spec:
ports:
- port: 80
targetPort: 80
selector:
app: runners-test
type: LoadBalancer
deployment file:
apiVersion: apps/v1
kind: Deployment
metadata:
name: runners-test
labels:
app: runners-test
spec:
replicas: 1
selector:
matchLabels:
app: runners-test
template:
metadata:
labels:
app: runners-test
spec:
containers:
- name: runners-test
image: mylocaldockerimage
ports:
- containerPort: 80
C02X67GOKL:terraform$ kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP > PORT(S) AGE
kubernetes ClusterIP 10.100.0.1 443/TCP 8d
runners-test LoadBalancer 10.100.246.180 af3884a05ad7811e99b0e06a70e73221-192467907.us-west-2.elb.amazonaws.com 80:31038/TCP 43m
It's targeting to port a random port 31038, when i connect to my pod and run ps -ef, i can see that a service is running on port 80.
As mentioned in the Kubernetes Service documentation , setting this type will enforce the underlying cloud provider to assign a public IP address to your service and route the traffic on your exposed port ( which is 80 in your case ) to Node Port ( 31038 ) on the kubernetes cluster level.
On cloud providers which support external load balancers, setting the type field to LoadBalancer provisions a load balancer for your Service.
I am trying to learn how to use Kibernetes with Minikube and have the following deployment and service:
---
kind: Service
apiVersion: v1
metadata:
name: exampleservice
spec:
selector:
app: myapp
ports:
- protocol: "TCP"
# Port accessible inside cluster
port: 8081
# Port to forward to inside the pod
targetPort: 8080
# Port accessible outside cluster
nodePort: 30002
type: LoadBalancer
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: myappdeployment
spec:
replicas: 5
template:
metadata:
labels:
app: myapp
spec:
containers:
- name: myapp
image: tutum/hello-world
ports:
- containerPort: 8080
I expect to be able to hit this service from my local machine at
http://192.168.64.2:30002
As per the command: minikube service exampleservice --url but when I try to access this from the browser I get a site cannot be reached error.
Some information that may help debugging:
kubectl get services --all-namespaces:
NAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
default exampleservice LoadBalancer 10.104.248.158 <pending> 8081:30002/TCP 26m
default kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 2h
default user-service-service LoadBalancer 10.110.181.202 <pending> 8080:30001/TCP 42m
kube-system kube-dns ClusterIP 10.96.0.10 <none> 53/UDP,53/TCP,9153/TCP 2h
kube-system kubernetes-dashboard ClusterIP 10.110.65.24 <none> 80/TCP 2h
I am running minikube on OSX.
This is expected.
Do note that LoadBalancer is for cloud to create external load balancer like ALP/NLP in AWS and something similar in GCP/Azure etc.
Update the service as shown here. here i assume 192.168.64.2 is your minikube ip. if not, update it with minikube ip to make it work.
kind: Service
apiVersion: v1
metadata:
name: exampleservice
spec:
selector:
app: myapp
ports:
- protocol: "TCP"
# Port accessible inside cluster
port: 8081
# Port to forward to inside the pod
targetPort: 80
# Port accessible outside cluster
nodePort: 30002
type: LoadBalancer
externalIPs:
- 192.168.64.2
Now you can access your application at http://192.168.64.2:8081/
If you need to access the application at 30002, you can use it like this
kind: Service
apiVersion: v1
metadata:
name: exampleservice
spec:
selector:
app: myapp
ports:
- protocol: "TCP"
# Port accessible inside cluster
port: 8081
# Port to forward to inside the pod
targetPort: 80
# Port accessible outside cluster
nodePort: 30002
type: NodePort
Your deployment file does not look correct to me.
delete it
kubectl delete deploy/myappdeployment
use this to create again.
apiVersion: apps/v1beta1
kind: Deployment
metadata:
labels:
app: myapp
name: myappdeployment
spec:
replicas: 5
selector:
matchLabels:
app: myapp
strategy: {}
template:
metadata:
labels:
app: myapp
spec:
containers:
- image: tutum/hello-world
name: myapp
ports:
- containerPort: 80
NOTE: Minikube support LoadBalancer services (via minikube tunnel)
you can get the IP and port through which you
can access the service by running
minikube service kubia-http #=> To open a browser with an IP and port
OR
minikube service kubia --url #=> To get the IP and port in the terminal
I have the following deployment file
apiVersion: apps/v1
kind: Deployment
metadata:
name: family-tree-deployment
labels:
app: familytree
spec:
replicas: 1
selector:
matchLabels:
app: familytree
template:
metadata:
labels:
app: familytree
spec:
containers:
- name: familytree
image: index.docker.io/koustubh/familytree:v1.0
ports:
- containerPort: 8080
I could successfully create the deployment using kubectl create -f deploy.yml
Now, I simply exposed this deployment with the following command
kubectl expose deployment family-tree-deployment --type=LoadBalancer --name=familytree-service
The service was successfully created.
The output is
$ kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
familytree-service LoadBalancer 10.51.244.161 35.221.113.235 8080:30505/TCP 1h
$ kubectl describe svc familytree-service
Name: familytree-service
Namespace: default
Labels: app=familytree
Annotations: <none>
Selector: app=familytree
Type: LoadBalancer
IP: 10.51.244.161
LoadBalancer Ingress: 35.221.113.235
Port: <unset> 8080/TCP
TargetPort: 8080/TCP
NodePort: <unset> 30505/TCP
Endpoints: 10.48.4.7:8080
Session Affinity: None
External Traffic Policy: Cluster
Events: <none>
I could login to the pod and I made sure the service is working.
However, when I use the external ip of the load balancer and query my api, the connection times out.
I have made sure firewall allows port 8080.
My application is running on port 8080
The generated Service object looks perfectly valid, so we can exclude a label issue or a missing public IP address. Besides you can access your Service internally, which means the firewall rule was applied incorrectly, most likely.
Please ensure you allow incoming traffic as follows
from the internet to the load balancer on TCP port 8080
from the load balancer to all Kubernetes nodes on TCP port 30505