My infrastructure is based on Kubernetes (k3s, with istio ingress). I would like to use istio to expose an application that is not in my cluster.
outside (internet) --https--> my router --> [cluster] istio --> [not cluster] application (192.168.1.29:8123)
I tried creating a HAProxy container, but it didn't work...
Any ideas?
If you insist on piping your traffic to the non-cluster application through the Kubernetes cluster, there are a couple of ways to handle this. You could use a Kubernetes-native ExternalName Kubernetes service.
The Istio way would be to create a ServiceEntry, though, and then use a VirtualService combined with a Gateway to direct traffic to your application outside of the cluster.
Related
Exposing Service from a BareMetal(Kubeadm) Build Kubernetes Cluster to the outside world. I am trying to access my Nginx as a service outside of the cluster to get NGINX output in the web browser.
For that, I have created a deployment and service for NGINX as shown below,
As per my search, found that we have below to expose to outside world
MetalLb
Ingress NGINX
Some HELM resources
I would like to know all these 3 or any more approaches in such way it help me to learn new things.
GOAL
Exposing Service from a BareMetal(Kubeadm) Built Kubernetes Cluster to the outside world.
How Can I make my service has its own public IP to access from the outside cluster?
You need to set up MetalLB to get an external IP address for the LoadBalancer type services. It will give a local network IP address to the service.
Then you can do port mapping (configuration in the router) of incoming traffic of port 80 and port 443 to your external service IP address.
I have done a similar setup you can check it here in detail:
https://developerdiary.me/lets-build-low-budget-aws-at-home/
You need to deploy an ingress controller in your cluster so that it gives you an entrypoint where your applications can be accessed. Traditionally, in a cloud native environment it would automatically provision a LoadBalancer for you that will read the rules you define inside your Ingress object and route your request to the appropriate service.
One of the most commonly used ingress controller is the Nginx Ingress Controller. There are multiple ways you can use to deploy it (mainfests, helm, operators). In case of bare metal clusters, there are multiple considerations which you can read here.
MetalLB is still in beta stage so its your choice if you want to use. If you don't have a hard requirement to expose the ingress controller as a LoadBalancer, you can expose it as a NodePort Service that will accessible across all your nodes in the cluster. You can then map that NodePort Service in your DNS so that the ingress rules are evaluated.
I've different deployments over different namespaces and I would like to expose some of them to the Internet, even if I don't have a static and public IP available.
The different services are deployed on Rancher k3s and every service which should be publicly accessible has an Ingress defined in the same namespace.
I was trying to follow Rancher - How to expose my services publicly?, but I didn't really get what I've to do and, moreover:
Why do we need to define a LoadBalancer? It seems to me that the IngressController used by k3s (Traefik?) already creates one. If this is a must (or a good way to go), how it should the service defined exactly?
I don't have any Rancher UI in my environment. Therefore, is there a way to achieve what described in that link in a declarative way?
Is there a way to use services like No-IP or FreeDNS for the final hostname?
If I get it right, you deployed Kubernetes manually on barebone/vms nodes and now you want to reach you deployments running inside that cluster.
There is two level of loadbalancing in this setup, the one managed by your ingress controller, sounds like it is traefik in your case, and it is recommanded to run a second L4 load balancer in front of your workers to reach the ingress pods that are usually deployed on multiple/all nodes. Traefik, or other lb controllers, will load balancer traffic inside the k8s cluster without issue even if you don't have a L4 load balancer, but it is not recommanded as if you loose this node, no traffic can reach the kubernetes cluster anymore. You "just" need to have your dns resolution pointing at your public ip and routed to one of your worker, or the LB in front of it. However, if you don't have a L4 LB, you'll need to have your ingress pods listening on ports 80 and/or 443.
Most things that you do in Rancher UI is just an easier way to see your k8s objects, all ingress configuration can be achieved via kubectl, k9s (strongly recommand thatone!), lens or other methods. However k8s objects are still k8s objects. In this case, you need to have your services exposed with ClusterIP that are then reachable by the ingress pods.
I've never used such a solution natively from k8s, but when I had too the internet router was able to do this part, once you're there, it is internal routing.
I hope this helps. Ingress can definitely be a tough one to grasp!
I have a monolithic application that is being broken down into domains that are microservices. The microservices live inside a kubernetes cluster using the istio service mesh. I'd like to start replacing the service components of the monolith little by little. Given the UI code is also running inside the cluster, microservices are inside the cluster, but the older web api is outside the cluster, is it possible to use a VirtualService to handle paths I specify to a service within the cluster, but then to forward or proxy the rest of the calls outside the cluster?
You will have to define a ServiceEntry so Istio will be aware of your external service. That ServiceEntry can be used as a destination in a VirtualService. https://istio.io/latest/docs/reference/config/networking/virtual-service/#Destination
Hello I'm new to Istio and currently learning about Istio.
As per my understanding, Envoy proxy will resolve an IP address of destination instead of Kube DNS server. Envoy will send traffic directly to healthy pod based on information which received from control pane.
So... Does Kubernetes service required to setup, if I'm using Istio?
Correct me if I'm wrong.
Thanks!
From the docs
In order to direct traffic within your mesh, Istio needs to know where
all your endpoints are, and which services they belong to. To populate
its own service registry, Istio connects to a service discovery
system. For example, if you’ve installed Istio on a Kubernetes
cluster, then Istio automatically detects the services and endpoints
in that cluster.
So Kubernetes service is needed for istio to achieve service discovery i.e to know the POD IPs. But kubernetes service(L4) is not used for load balancing and routing traffic because L7 envoy proxy does that in istio.
From the docs.
A pod must belong to at least one Kubernetes service even if the pod
does NOT expose any port. If a pod belongs to multiple Kubernetes
services, the services cannot use the same port number for different
protocols, for instance HTTP and TCP.
I run istio on Kubernetes. I want to know how the envoy sidecar works. For example, after sidecar is injected into the pod, the original container cannot access the outer network without EgressRule. How does it work?
All the traffic inside the pod is captured by iptables commands and directed to the sidecar proxy. Then the sidecar proxy performs routing, according to routing tables it receives from Istio Pilot (a part of the Istio Control Plane). The routing tables are based on the Kubernetes services and on the Istio RouteRules. Since Istio cannot know anything about the external services, it cannot route the traffic to the external services without an EgressRule defined. EgressRules define the routing tables for the external services.