I have a Kubernetes cluster deployed locally with Kubeadm/Vagrant with a master and two workers with the following IPs:
master: 192.168.250.10
worker1: 192.168.250.11
worker2: 192.168.250.12
then I have an application composed by a ReactJS frontend and SpringBoot backend running in two separate containers on the same Pod. When I submit a form on the frontend the application calls an API in the backend that internally calls a Kubernetes API. To authenticate to the cluster I use a .kube/config file correctly configured.
When the application (frontend/backend) is outside the cluster everything works fine. I use docker-compose to startup the two containers just for the unit tests. The .kube/config file has as API URL https://192.168.250.10:6443. The problem is when I try to run the application in the containers the IP 192.168.250.10 doesn't work properly and communication goes in Timeout exception.
I am sure the application is OK because the same application works fine in IBM Cloud wherein .kube/config there is an API server with public IP reachable.
My question is, which IP should I put into .kube/config when I run the application locally inside my cluster? How can I get this IP using kubectl commands?
Thanks in advance for any help.
Related
Is there any other way except port-forwarding, I can access the apps running inside my K8s cluster via http://localhost:port from my host operating system.
For example
I am running minikube setup to practise the K8s and I deployed three pods along with their services, I choose three different service type, Cluster IP, nodePort and LoadBalancer.
For Cluster IP, I can use port-forward option to access my app via localhost:port, but the problem is, I have to leave that command running and if for some reason, it is distributed, connection will be dropped, so is there any alternate solution here ?
For nodePort, I can only access this via minikube node IP not with the localhost, therefore, if I have to access this remotely, I wont have a route to this node IP address
For LoadBalancer, not a valid option as I am running minikube in my local system not in cloud.
Please let me know if there is any other solution to this problem, the reason why I am asking this when I deploy same application via docker compose, I can access all these services via localhost:port and I can even call them via VM_IP:port from other systems.
Thanks,
-Rafi
I have a cluster with 3 nodes. In each node i have a frontend application running in a Pod and backend application running in a separate Pod.
I send data from the frontend application to the backend application, to do this i utilise the Cluster IP Service and k8 dns resource.
I also have a function in my frontend where i send data to a separate service unrelated to my k8s cluster. I send this data using a standard AJAX request to a url with a payload i.e http://my-seperate-service-unrelated-tok8.com.
All of this works correctly and the cluster operates as i want. - i have this cluster deployed to GKE.
I now want to run this cluster local using minikube, which i have been able to do, however, when i am running locally i do not want to send data to my external service - instead i want to forward it to either a new Pod i will create or just not send it.
The problem here is i need a proxy to intercept outgoing network traffic, check if the outgoing request is the request i am looking for and if it is then redirect it.
I understand each node running in a cluster has a kube-proxy service running within the node - which is used to forward traffic to the relevant services in the cluster.
I would like to either extend this service, or create a new proxy service where i can listen for outgoing traffic to a specific url and redirect it.
Is this possible to do in a k8 cluster? I assume there is a Service i can create to listen for all outgoing requests and redirect specific requests based on rules i set.
I wasn’t sure if k8 clusters have a Service already configured i can simply add to - that’s why i thought of the kube-proxy, would anyone be able to advice on this?
I wanted to add this proxy so i don’t have to change my code when its ran locally in minikube or deployed to GKE.
Any help is greatly appreciated. Thanks!
I did a tool that help you to forward a service to another service,local port, service from other cluster, etc...
This way you can have exactly your same urls, ports and code... but the underlying services gets "replaced", if I understand correctly this is what you are looking for.
Here is a quick example of an stage service being replaced with my local 3000 port
This is the repository with more info and examples: linker-tool
If you are interested let me know if you need help or have any question.
I have minikube running kubernetes inside a virtual box.
one of the docker container it runs is an ignite server.
during my development I try to access the ignite server from outside java client but the discovery fails with all configurations I tried.
is it possible at all?
If yes can someone give an example?
To enable Apache Ignite nodes auto-discovery in Kubernetes, you need to enable TcpDiscoveryKubernetesIpFinder in IgniteConfiguration. Read more about this on https://apacheignite.readme.io/docs/kubernetes-deployment. Your Kubernetes service definitions should have the container exposed port specified, then minikube should give you service URL after successful deployment.
I have set up a kubernetes Cluster manually. The cluster is healthy. The nodes are up. The pods and services are also created and running.
I have a web pod which is a python flask application. A db-pod which is redis. Exposed redis as a service to be accessible from python. Exposed web pod as external service also. The external service is running in 31727 port.
When i access the web application through browser, it reports redis host is not accessible.
The application works well when deployed in a kubernetes cluster created using kubeadm/kops.
Sounds like kube-proxy or overlay networking issue at first glance. Are you sure kube-proxy is launched on nodes and you have a working overlay ? Can you ping pods directly on a pod-to-pod basis ?
Update: as your pod-to-pod connectivity is down, you need to look into your flannel configuration, and make sure it works fine, as well as make sure pods are started with flannel networking (ie. via CNI) rather than local docker0 interfaces network.
I have two kubernetes controllers and services with pods running named web and api respectively.
In my web pod I am using superagent to try and access an api pod with the following http://api:3000/api/user this results in the error ERR_NAME_NOT_RESOLVED
However if I run a shell on my web pod and curl http://api:3000/api/user everything works as it should
Am I missing something fundamental about how superagent works? Or something else?
If you launch your superagent in a browser, the browser is not a part of Kubernetes cluster, hence it neither uses kube DNS nor can it access cluster IPs.
To make it work you need to expose your api service to the external world by means of NodePort/Loadbalancer service or Ingress