I have a very simple springboot service deployed on minikube in windows 10.
C:\Software\Kubernetes>kubectl get deployments
NAME READY UP-TO-DATE AVAILABLE AGE
myspringbootserver 1/1 1 1 68m
C:\Software\Kubernetes>kubectl get service
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 49d
myspringbootserver NodePort 10.110.179.207 <none> 9080:30451/TCP 6m50s
C:\Software\Kubernetes>minikube service myspringbootserver --url
http://192.168.99.101:30451
But when I try to hit the service from my chrome browser with url
http://192.168.99.101:30451/MySpringBootServer/heartbeat
getting connection refused exception.Not sure what is going wrong.Could anyone help to resolve it please?
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Can you curl or wget using the IP address of the pod?
For example kubectl exec -it podname -- curl http://podip:9080/MySpringBootServer/heartbeat
if not, ensure the path is correct
if yes, make sure the pod exists as an endpoint of the service
kubectl get endpoints myspringbootserver
there is a good debugging document regarding services here:
https://kubernetes.io/docs/tasks/debug-application-cluster/debug-application/#debugging-services
Related
I run a local kubernetes cluster (Minikube) and I try to connect pgAdmin to postgresql, bot run in Kubernetes.
What would be the connection string? Shall I access by service ip address or by service name?
kubectl get service
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
dbpostgresql NodePort 10.103.252.31 <none> 5432:30201/TCP 19m
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 3d21h
pgadmin-service NodePort 10.109.58.168 <none> 80:30200/TCP 40h
kubectl get ingress:
NAME CLASS HOSTS ADDRESS PORTS AGE
pgadmin-ingress <none> * 192.168.49.2 80 40h
kubectl get pod
NAME READY STATUS RESTARTS AGE
pgadmin-5569ddf4dd-49r8f 1/1 Running 1 40h
postgres-78f4b5db97-2ngck 1/1 Running 0 23m
I have tried with 10.103.252.31:30201 but without success.
Inside the cluster, services can refer to each other by DNS based on Service object names. So in this case you would use dbpostgresql or dbpostgresql.default.svc.cluster.local as the hostname.
Remember minikube is running inside its' own container, the NodePort clusterIPs you're getting back are open inside of minikube. So to get minikube's resolution of port and ip, run: minikube service <your-service-name> --url
This will return something like http://127.0.0.1:50946 which you can use to create an external DB connection.
Another option would be to use kubectl to forward a local port to the service running on localhost ex. kubectl port-forward service/django-service 8080:80
I installed microk8s on my ubuntu machine based on steps here https://ubuntu.com/kubernetes/install#single-node
Then I followed kubernetes official tutorial and created and exposed a deployment like this
microk8s.kubectl create deployment kubernetes-bootcamp --image=gcr.io/google-samples/kubernetes-bootcamp:v1
microk8s.kubectl expose deployment/kubernetes-bootcamp --type=NodePort --port 8083
This is my kubectl get services output
akila#ubuntu:~$ microk8s.kubectl get services
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.152.183.1 <none> 443/TCP 25h
kubernetes-bootcamp NodePort 10.152.183.11 <none> 8083:31695/TCP 17s
This is my kubectl get pods output
akila#ubuntu:~$ microk8s.kubectl get pods
NAME READY STATUS RESTARTS AGE
kubernetes-bootcamp-6f6656d949-rllgt 1/1 Running 0 51m
But I can't access the service from my browser using http://localhost:8083 OR using http://10.152.183.11:31695
When I tried http://localhost:31695 I'm getting ERR_CONNECTION_REFUSED.
How can I access this "kubernetes-bootcamp" service from my browser ?
Am I mising anything ?
The IP 10.152.183.11 is CLUSTER-IP and not accessible from outside the cluster i.e from a browser. You should be using http://localhost:31695 where 31695 is the NodePort opened on the host system.
The container of the gcr.io/google-samples/kubernetes-bootcamp:v1 image need to listen on port 8083 because you are exposing it on that port. Double check that because otherwise this will lead to ERR_CONNECTION_REFUSED error.
If the container is listening on port 8080 then use below command to expose that port
microk8s.kubectl expose deployment/kubernetes-bootcamp --type=NodePort --port 8080
Try this
kubectl port-forward <pod_name> <local_port>:<pod_port>
then access http://localhost:<local_port>
Here is the output of minikube dashbaord
ubuntu#ip-172-31-5-166:~$ minikube dashboard
* Enabling dashboard ...
* Verifying dashboard health ...
* Launching proxy ...
* Verifying proxy health ...
* Opening http://127.0.0.1:45493/api/v1/namespaces/kubernetes-dashboard/services/http:kubernetes-dashboard:/proxy/ in your default browser...
- http://127.0.0.1:45493/api/v1/namespaces/kubernetes-dashboard/services/http:kubernetes-dashboard:/proxy/
I have enabled port 45493 at Security Group Level and also on Linux VM. However,, when I'm trying to access the Kube dashboard, I don't have luck
wget http://13.211.44.210:45493/
--2020-04-16 05:50:52-- http://13.211.44.210:45493/
Connecting to 13.211.44.210:45493... failed: Connection refused.
However, when I do the below, it works and produces index.html file with status code 200
wget http://127.0.0.1:45493/api/v1/namespaces/kubernetes-dashboard/services/http:kubernetes-dashboard:/proxy/
--2020-04-16 05:52:55-- http://127.0.0.1:45493/api/v1/namespaces/kubernetes-dashboard/services/http:kubernetes-dashboard:/proxy/
Connecting to 127.0.0.1:45493... connected.
HTTP request sent, awaiting response... 200 OK
Steps to reproduce at high level is as below:
EC2 Ubuntu of size t2.large
Install minikube, minikube start --driver=docker
Perform deployment as like kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v2.0.0-beta8/aio/deploy/recommended.yaml
kubectl get pods -n kubernetes-dashboard
NAME READY STATUS RESTARTS AGE
dashboard-metrics-scraper-84bfdf55ff-xx8pl 1/1 Running 0 26m
kubernetes-dashboard-bc446cc64-7nl68 1/1 Running 0 26m
5.kubectl get svc -n kubernetes-dashboard
TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
dashboard-metrics-scraper ClusterIP 10.102.85.110 <none> 8000/TCP 40m
kubernetes-dashboard ClusterIP 10.99.75.241 <none> 80/TCP 40m
My question is why I'm unable to access the internet?
This is by design, minikube is a development tool for local environments.
You can deploy an ingress or loadbalancer service to expose the dashboard, if you really know what you are doing.
I'm learning about Kubernetes and ingress controllers but I'm stucked getting this error when I try to apply kong ingress manifest...
ingress-kong-7dd57556c5-bh687 0/2 Init:0/1 0 29s
kong-migrations-gzlqj 0/1 Init:0/1 0 28s
postgres-0 0/1 Pending 0 28s
Is it possible to run this ingress on my home server without minikube ? If so, how?
Note: I have a FQDN pointing to my home server.
I guess you run manifest from Github
Issues with Pods
I have reproduced your case. As you have 3 pods, you have used option with DB.
If you will describe pods using
$ kubectl describe pod <podname> -n kong
you will receive error output:
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Warning FailedScheduling 7s (x4 over 17s) default-scheduler pod has unbound immediate PersistentVolumeClaims (repeated 2 times)
You can also check job in kong namespace.
It is work correctly on fresh Minikube cluster, so I guess you might apply same changes to storageclass.
Is it possible to run this ingress on my home server without minikube ? If so, how?
You have to use Kubernetes to do it. Since Minikube is supporting LoadBalancer you can can use it in Home.
You can check this thread about FQDN. As mentioned:
The host machine should be able to resolve the name of that FQDN. You
might add a record into the /etc/hosts at the Mac host to achieve
that:
10.0.0.2 mydb.mytestdomain
But in your case it should be IP address of LoadBalancer, kong-proxy.
Obtain LoadBalancer IP in Minikube
If you will deploy everything correctly you can check your services.
$ kubectl get svc -n kong
You will see kong-proxy service with LoadBalancer type wit <pending> EXTERNAL-IP.
To obtain ExternalIP you have to use minikbue tunnel.
Please note that you need have $ sudo minikube tunnel run in one console whole time.
Before Minikube tunnel
$ kubectl get svc -n kong
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kong-proxy LoadBalancer 10.110.218.74 <pending> 80:31881/TCP,443:31319/TCP 103m
kong-validation-webhook ClusterIP 10.108.204.137 <none> 443/TCP 103m
postgres ClusterIP 10.105.9.54 <none> 5432/TCP 103m
After
$ kubectl get svc -n kong
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kong-proxy LoadBalancer 10.110.218.74 10.110.218.74 80:31881/TCP,443:31319/TCP 104m
kong-validation-webhook ClusterIP 10.108.204.137 <none> 443/TCP 104m
postgres ClusterIP 10.105.9.54 <none> 5432/TCP 104m
Testing Kong
Here you can find how to get start with Kong. It will show you how to create Ingress. Later as I mentioned you have to edit ingress and add rule (host) similar like in K8s docs.
Having a kubernetes service (of type ClusterIP) connected to a set of pods, but none of them are currently ready - what will happen to the request?
Will it:
fail eagerly
timeout
wait until a ready pod is available (or forever, whichever is earlier)
something else?
It will time out.
Kube-proxy pulls out the IP addresses from healthy pods and sets as endpoints of the service (backends). Also, note that all kube-proxy does is to re-write the iptables when you create, delete or modify a service.
So, when you send a request within your network and there is no one to reply, your request will timeout.
Deployed nginx service
[node1 ~]$ kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 443/TCP 2h
my-nginx ClusterIP 10.100.1.134 80/TCP 9s
$ curl 10.100.1.134
curl: (7) Failed connect to 10.100.1.134:80; Connection refused
Deployed nginx deployment
$ kubectl create -f nginx-depl.yaml
$ kubectl get po
NAME READY STATUS RESTARTS AGE
my-nginx-f9945ffdd-2f77f 1/1 Running 0 1m
my-nginx-f9945ffdd-rk68v 1/1 Running 0 1m
$ curl 10.100.1.134
Welcome to nginx!
most likely you would get Connection refused error