Kong Ingress Controller is a dynamic and
highly available Ingress Controller which configures Kong
using Ingress resources created in your Kubernetes cluster.
In addition, it can configure plugins, load balancing, health checking
on your services running in Kubernetes.
Ingress Controller is a Golang application that talks to Kubernetes API server and translates Kubernetes resources into Kong.
Kong Ingress controller can be deployed in any Kubernetes cluster which is running Kong. Ingress Controller does not pose any limitations on how Kong is deployed in your Kubernetes environment. All it needs, is access to Kubernetes API server and Admin API of Kong which it uses to configure Kong.
The Admin API of Kong can be running on Data-Plane Kong nodes or Kong nodes running Control-Plane and Data-plane, both at the same time.
In the above deployment figure, a Kong Control-Plane pod is deployed alongside the Ingress Controller pod. As mentioned above, this is only one way of deploying Kong with Ingress Controller and it won't matter how we do it.
Kong's state is stored in Postgres (can be Cassandra) which should be deployed as a StatefulSet and all Kong nodes in your Kubernetes cluster should be able to connect to the database.
Please check out Deployment Guides for more details on how to deploy Kong with Ingress Controller.
Multiple instances of Kong Ingress Controller pod can be deployed. The Ingress Controller uses a leader election protocol and elects a leader. At any point, only one leader Controller pod will be configuring Kong and other follower pods will be ready to take over as soon as the leader fails.
If Kong is deployed in Control-plane and Data-plane mode, then Kong proxy can be scaled independently. By using this approach we can deploy and scale the data-plane with the requirements of your applications, i.e. using a DaemonSet, a deployment with affinity rules, HorizontalPodAutoscaler etc.
Kong Ingress Controller is a translator from Kubernetes resources to resources in Kong.
Following figure shows how resources in Kubernetes are translated into Kong's data model:
The figure shows the translation of Ingress resource, services and pods in Kubernetes to corresponding resources in Kong.
There are a few Custom Resource Definitions(CRDs) available that can be used to configure plugins, health checks, load balancing, consumers, their credentials in Kong using the Ingress Controller.
Please read through our Custom Resources documentation for details.