Let’s assume the request gets load balanced on a pod running on node 3. In Azure, the service is exposed through an Azure Load Balancer. Let’s assume we have 3 nodes (3 VMs) in our AKS cluster.Īs mentioned, an Ingress Controller is a service of type load balancer. services ingresses call into, are of type Cluster IP since they only need to be reached from within the cluster. This is similar to Azure Application Gateway which is implemented as a set of VMs fronted with an Azure Load Balancer. The ingress routes traffic to a service which then route it to a pod.Īn ingress controller is implemented as a Kubernetes Service of type load balancer. Conceptual communicationĬonceptually, the communication pattern goes a bit like this: We could reuse a service in multiple rules. Of course, we could combine both previous approaches.Īs the diagram suggests, an ingress has a many-to-many relationship with services. For instance, an ingress takes requests for and forwards requests under to the pizza-offers service and requests under to the pizza-menu service.Īnother one is hosting multiple domain names on the same ingress (e.g. The first one is what in Application Gateway parlance we would call URL Based routing. We can then upgrade our anatomy knowledge as follow: Ingress acts as a front door to services. It understands the host header, the path and can handle TLS termination.Īn ingress also is a reverse proxy: it generates a new HTTP requests to the underlying service. It is a question of Layer 4 (Service) vs Layer 7 (Ingress) load balancing. Now that we have a service that we can connect to, what is the need for Ingress? We described a service as offering a stable IP, load balancing a group of pods and typically realized through a replica set. We used the following diagram to describe the anatomy of a service: We discussed the integration Kubernetes & Azure Networking within AKS in a past article. Book Kubernetes in Action by Marko Luksa, specifically chapter 5: the book is available on Safari Book Online.Azure AKS documentation online: there are multiple articles on Ingress covering different topics this gives example on AKS.Ingress documentation from Kubernetes.io: this is Azure agnostic it explains the concepts & give generic examples.If you want to ramp up on Ingress in AKS, I would suggest the following readings, in order: There will be no code nor even Portal tour. So, I thought I would share this sense of simplicity. I found the concept of Ingress utterly confusing at first. I did a bit of experimentation with Kubernetes Ingress, more specifically NGINX, lately. Menu About Ingress in Azure Kubernetes Service (AKS) Solution

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