I have been working on a very innovative project which involves both Kubernetes and Istio. So, I have 2-node kubernetes cluster setup with istio installed withe their side cars in the pods. I have already hosted the bookinfo application in the nodes but by using a separate VM by following the procedures given in Istio Mesh-Expansion.
So I have VM where the details and Mysqldb pods are present. The other pods are running in the k8s cluster. So Now, They communicate within a private network.
So my next phase of project would require me to setup Kube-proxy separately without installing Kubernetes in the VM, so as to allow it to directly communicate to the Kube-Api Server running in the master nodes of the k8s cluster through the private network. Hence, Can anybody suggest a way how to go about this?
All components of Kubernetes should be connected to the kube-api. Otherwise, they will not work.
So my next phase of project would require me to setup Kube-proxy separately without installing Kubernetes in the VM, so as to allow it to directly communicate to the Kube-Api Server running in the master nodes of the k8s cluster through the private network.
To access the kube-api server using Service with the private ClusterIP address, you should already have a kube-proxy. So, it is impossible to use any ClusterIP private address until you setup kube-proxy which is communicating with your kube-api by its address outside the Cluster IP range.
Kube-api can be exposed using NodePort or LoadBalancer type of service.
Related
I want to deploy a website on my kubernetes cluster.
I followed this guide to set up my kubernetes cluster on my set of raspberries. Now I have tested it with some nginx containers and it works to a certain degree since I need to find the correct ip of the machine it is deployed on.
Now that I have a signed up a domain I like to forward the traffic to my deployed website on my kubernetes cluster.
I have done this before with nginx, certbot and letsencrypt without containerisation. Now I am just missing the part how kubernetes handles the network. I assumed it was similar to swarms network which forwards all the request to the correct machine. But kubernetes does it differently.
TLDNR: How to deploy a website on a self build raspberry pi kubernetes cluster?
You need to create Kubernetes Service (documentation) to expose the web service to the outside world.
There are two types of Services relevant to deployments outside of cloud providers:
ClusterIP: Exposes the Service on a cluster-internal IP. Choosing this value makes the Service only reachable from within the cluster.
This is the default ServiceType.
NodePort: Exposes the Service on each Node's IP at a static port (the NodePort). A ClusterIP Service, to which the NodePort Service
routes, is automatically created. You'll be able to contact the NodePort Service, from outside the cluster, by requesting <NodeIP>:<NodePort>.
So what you probably want is a NodePort service, which will expose the service on some fixed port on each of your Nodes (documentation and examples)
I have installed my kubernetes cluster on Jelastic. Now, I tried to define a service of LoadBalancer type and would like it to be provided with an external IP. The external IP is currently marked as pending. What should I do to make it non-pending? Do I have to provide the worker nodes with an external IPv4?
In my current setup, my worker nodes have no IPv4 because I put an nginx load-balancer in front of the cluster:
The IPv4 is set on the nginx node. Is that a problem? If I want to access my loadbalancer service inside of my kubernetes cluster, what should I do?
For LoadBalancer service type to work, the cloud provider must implemenet the relevant APIs to get it to work.
With regard to Jelastic, as per their docs, they don't support it https://docs.jelastic.com/kubernetes-exposing-services/:
Jelastic PaaS does not support the LocaBalancer service type currently.
In Jelastic Public IP addresses have to be attached to worker nodes.
Every worker node has ingress controller instance running (based oт nginx/haproxy/traefik) with http/https listeners that can forward traffic to the required service.
You have just to bind your domain as CNAME to Environment FQDN and every your worker node can accept requests in RR-DNS mode.
Does this scenario works for you or you have a specific requirement to use external load balancer?
By default, when Public IPs are not attached to worker instances the traffic is going through the Shared Load Balancer.
P.S. If you install Certification Manager Addon to your K8s cluster - you can also issue free Let's Encrypt certificates.
I am deploying Redis and a sentinel architecture on Kubernetes.
when I work with deployments are my cluster that requires redis all is working fine.
the problem is that some services of my deployment are located on a different kubernetes cluster.
when the clients reach the redis sentinel ( which I exposed via NodePort that maps internally to 26379) they get an reply the master IP.
that actually happens is that they are getting the redis Master kubernetes IP and the internal port 6379.
as I said while working in KUbernetes that works fine since the clients can access that IP but when the a services are external it is not reachable.
I found that there is a configuration named:
cluster-announce-ip and cluster-announce-ip
I have set those values to the external IP of the cluster and the external port hoping that it will solve the problem but still no change.
I am using the formal docker image : redis:4.0.11-alpine
any help would be appreciated
I have a requirement that the server that is running inside one of my container in a k8s cluster should be able to reach a server that is running in some other machine (currently its in AWS).Now the problem is that both the server (in AWS & Kubernetes Cluster) should be able to reach each other.
My server in AWS is not able to ping my Server running in Kubernetes Cluster.
Is that possible? Can we do it ?
Yes you can use ingress-nginx to create publicly reachable services ingress-nginx
If you want to do it manually you can setup load balancers that map to specific ip ranges for your nodes. This is for ssh traffic.
yes you can use ingress kubernetes object it will create publicly reachable services.
Mainly if you are using aws or digital-ocean and you will use ingress it will make load balancer (ELB or ALB) and make public service and you can access server running inside kubernetes
By manually also you can do it just simply use kubernetes service and expose it using load balancer and NODE port
https://kubernetes.io/docs/concepts/services-networking/service/
I am trying to deploy my sample micro service Docker image in Kubernetes cluster having 2 node. I explored everything about Pods, Services, Deployment, StatefulSets and Daemon-sets etc.
I am trying to create a sample deployment and Service for that. Here I explored about how deployment provides the scalability and load balancing functionality. And exploring about service discovery by providing Services ClusterIp.
I have two questions:
My scenario is that I am trying to deploy microservice on my on-premise Ubuntu machine. The machine has the IP address of 192.168.1.15. When I am referring Kubernetes, service will also have one clusterIP.
If my microservice end point is /api/v1/loadCustomer, how I can call this end point? Do I need to use clusterIP also ? Can I call simply 192.168.1.15:8080/api/v1/loadCustomers ?
What is the role of clusterIP when I am calling my end point ? Can I directly use port?
I am referring to the following link for exploration:
https://kubernetes.io/docs/concepts/services-networking/connect-applications-service/
tldr:
you can not access the application using the clusterIP from the outside of the cluster. you can access the application using either loadbalancer's IP (type=LoadBalaner) or Node's IP (type=NodePort).
benefit of clusterIP:
As you know that pods can be created and terminated during its life-cycle consequently IP (endpoint IP)address created and terminated.Therefore, clusterIP is static which does not depends of the life-cycle of the pods.
Long Answer
In a Kubernetes cluster
an application or pod has following abstraction.
Endpoint IP and Port:It is provided by the CNI Plugins such as flannel, calico.
Each pod has an IP and tragetPort which is UNIQUE.
you can list and watch the endpoints by the following commands.
kubectl get endpoints --all-namespaces
clusterIP and port : It is provided by the kube-proxy component.
The replicated pods share a clusterIP and Port.
Load-balancing of request to the replicated pods.
internally expose so that other pod can discover it
you can list and watch clusterIP and port with the following command
kubectl get services --all-namespaces
externalIP and port: It can be layer 3-4 load balancer's IP and port or node's IP and Nodeport.
if you want to use loadbalancer's IP and port, you can use type=LoadBalaner in service file.
If you want to use node's IP, you need to use type=NodePort in service file.