I am learning the world of k8s and there is a lot of talk about ingress and ingress controllers. Conceptually it sounds identical to a web server which I will define as a service that proxies HTTP requests to web application servers. It can serve up certificates and do basic load balancing...
Whereas ingress: Ingress exposes HTTP and HTTPS routes from outside the cluster to services within the cluster. Traffic routing is controlled by rules defined on the Ingress resource. Ingress may provide load balancing, SSL termination and name-based virtual hosting.
https://kubernetes.io/docs/concepts/services-networking/ingress/
They sound the same! So what exactly is the difference here? I can't be the only one confused by this right?
In general Web Server's is responsible for accepting and fulfilling requests from clients.
A web server‘s fundamental job is to accept and fulfill requests from clients for static content from a website (HTML pages, files, images, video, and so on). The client is almost always a browser or mobile application and the request takes the form of a Hypertext Transfer Protocol (HTTP) message, as does the web server’s response.
Lately you can find many web servers like Apache or Nginx.
Kubernetes Ingress is an API object. In IBM blog - What is Kubernetes Ingress and why is it useful?
Kubernetes Ingress is an API object that provides routing rules to manage external users' access to the services in a Kubernetes cluster, typically via HTTPS/HTTP. With Ingress, you can easily set up rules for routing traffic without creating a bunch of Load Balancers or exposing each service on the node. This makes it the best option to use in production environments.
Also in Kubernetes Ingress Docs you can find that Kubernetes Ingress needs Ingress Controller.
You must have an Ingress controller to satisfy an Ingress. Only creating an Ingress resource has no effect.
There are many ingress controllers like Nginx, Ambassador, Apache, etc.
To sum up:
To use Ingress you need some Web Server as Ingress Controller.
Kubernetes Ingress is an Kubernetes object which helps user to configure Web Server (like Nginx) in Kubernetes Clusters.
As you pointed in documentation it allows you to configure some HTTP/HTTPS routing, traffic load balancing, terminate SSL / TLS, etc.
Ingress exposes HTTP and HTTPS routes from outside the cluster to services within the cluster. Traffic routing is controlled by rules defined on the Ingress resource.
Related
I have configured NGINX as a reverse proxy with web sockets enabled for a backend web application with multiple replicas. The request from NGINX does a proxy_pass to a Kubernetes service which in turn load balances the request to the endpoints mapped to the service. I need to ensure that the request from a particular client is proxied to the same Kubernetes back end pod for the life cycle of that access, basically maintaining session persistence.
Tried setting the sessionAffinity: ClientIP in the Kubernetes service, however this does the routing based on the client IP which is of the NGINX proxy. Is there a way to make the Kubernetes service do the affinity based on the actual client IP from where the request originated and not the NGINX internal pod IP ?
This is not an option with Nginx. Or rather it's not an option with anything in userspace like this without a lot of very fancy network manipulation. You'll need to find another option, usually an app-specific proxy rules in the outermost HTTP proxy layer.
I am a bit confused with the architecture of load-balancing K8s traffic with Nginx ingress controller.
I learned that an ingress controller is supposed to configure the load-balancer you're using according to ingress configurations.
So if I want to use Nginx ingress controller and I have a Physical server that is running Nginx that stands in front of my network, how can I make the ingress controller configure it?
Ingress exposes HTTP and HTTPS routes from outside the cluster to services within the cluster. Traffic routing is controlled by rules defined on the Ingress resource. You must have an Ingress controller to satisfy an Ingress. Only creating an Ingress resource has no effect. Take a look at the example graph below:
Nginx Ingress Controller is using service of type LoadBalancer to get the traffic enter the controller and then to get rerouted to particular services.
I strongly suggest going through the official documentation in order to get a good understanding of the topic and see some examples of using it.
is the nginx ingress controller supposed to (or can) configure an
Nginx machine?
NGINX Ingress Controller works with both NGINX and NGINX Plus and supports the standard Ingress features - content-based routing and TLS/SSL termination.
So, here's what's up: We have HTTPs being handled externally by our nginx ingress on a kubernetes cluster. This is great and all, but it means any traffic between the proxy and its backing service is going over http. This is a bit of a flaw in our security coverage so we're trying to get that secondary internal traffic to travel over https as well.
Now, the ingress has a nginx.ingress.kubernetes.io/proxy-ssl-secret: secretName which should allow us to get the backend services certificates. But no matter how I setup the ca, etc, there service terminals before sending anything.
Background
I have an in-cluster Kubernetes pod/application that works fine when accessing it via an nginx-ingress ingress controller (requires specific Host HTTP header), but it cannot be accessed by other in-cluster pods/applications (i.e. for testing) due to the pods using different host names (e.g. service-name.namespace.svc.cluster.local) rather than the FQDN of the K8S master (in the LAN).
Plan So Far
I think the only way to (easily) resolve this is to setup an in-cluster forward-proxy nginx instance. Ideally, the service is either a side-car for the pod that needs to have headers re-written, or it needs to be a general in-cluster proxy that multiple services can access.
Question
How would I setup an in-cluster nginx forward proxy service?
Should it be a sidecar, or a general service any pod can access?
Work So Far
The linked "similar" questions don't appear to be helpful for my use case (i.e. don't show how to configure an in-cluster proxy), or are focused on proxying to IPs external to the cluster (i.e. I need to proxy HTTP requests, and re-write their headers, to in-cluster resources).
What is the difference between Nginx ingress controller and HAProxy load balancer in kubernetes?
First, let's have a quick overview of what an Ingress Controller is in Kubernetes.
Ingress Controller: controller that responds to changes in Ingress rules and changes its internal configuration accordingly
So, both the HAProxy ingress controller and the Nginx ingress controller will listen for these Ingress configuration changes and configure their own running server instances to route traffic as specified in the targeted Ingress rules. The main differences come down to the specific differences in use cases between Nginx and HAProxy themselves.
For the most part, Nginx comes with more batteries included for serving web content, such as configurable content caching, serving local files, etc. HAProxy is more stripped down, and better equipped for high-performance network workloads.
The available configurations for HAProxy can be found here and the available configuration methods for Nginx ingress controller are here.
I would add that Haproxy is capable of doing TLS / SSL offloading (SSL termination or TLS termination) for non-http protocols such as mqtt, redis and ftp type workloads.
The differences go deeper than this, however, and these issues go into more detail on them:
https://serverfault.com/questions/229945/what-are-the-differences-between-haproxy-and-ngnix-in-reverse-proxy-mode
HAProxy vs. Nginx