ingress-controller

README

Ingress controller

L7 Load Balancer service managing external load balancer provider configured via load balancer controller. Pluggable model allows different controller and provider implementation. v0.1.0 has support for Kubernetes ingress as an LB controller, and Rancher Load Balancer as a provider. Rancher LB provider is a default one, although you can develop and deploy your own implementation (nginx, ELB, F5, etc).

Design

• ingress-controller gets deployed as a containerized app with controller and provider names passed as an argument
• LB controller listens to the corresponding server events, generate load balancer config and pass it to the provider to apply.
• LB provider configures external load balancer, and pass LB public end point to the lb controller.
• LB controller propagates LB public end point back to the server.
• LB controller doesn't carry any provider implementation details; it communicates with the provider via generic provider interface using generic LB config.

Kubernetes as an LB controller and Rancher as an LB provider

When Kubernetes is passed as an LB controller argument, the app would be deployed to work as a Kubernetes Ingress controller. The controller listens to Kubernetes server events like:

• Ingress create/update/remove
• Backend services create/remove
• Backend services' endpoint changes

and generates LB config based on the Kubernetes ingress info. After config is generated, it gets passed to LB provider - Rancher provider in our case. The provider will create Rancher Load Balancer service for every Kubernetes ingress, and propagate Load Balancer public endpoint(s) back to the Controller. The controller in turn would update Kubernetes ingress with the Address = Rancher Load Balancer public endpoint (ip address of the host where Rancher Load Balancer is deployed):

> kubectl get ingress
NAME      RULE          BACKEND   ADDRESS
test      -                        104.154.107.202 // host ip address where Rancher LB is deployed
          foo.bar.com
          /foo           nginx-service:80

Rancher Load Balancer provider:

• Configures Rancher LB with hostname routing rules and backend services defined in Kubernetes ingress.
• Monitors Rancher LB public endpoint changes(LB instance gets redeployed on another host) and report them back to controller, so Kubernetes ingress will be updated accordingly.
• Manages Rancher LB lifecycle - destroy LB when ingress is removed, create LB once new ingress is added, update LB config when ingress is updated

Refer to kubernetes-ingress and kubernetes ingress-controller for more info on Kubernetes ingress and ingress controller implementation solutions.

Build ingress controller

You can build ingress controller using Rancher dapper tool. Just install Dapper, and run the command below from ingress-controller directory:

dapper

it would build the binaries and create an ingress-controller image.

Deploy ingress controller

Ingress controller with Kubernetes/Rancher support can be deployed as:

• part of Rancher system Kubernetes stack (recommended and officially supported way)
• as a pod container in Kubernetes deployed through Rancher with ability to access Rancher server API.

To fix in the future release

• Add TLS support.
• Support for custom public port. Today only standard http port 80 is supported as a public port, and we want to make it configurable.
• Horizontal scaling for Rancher LB service. Today it gets deployed with scale=1 (which is equal to 1 public endnpoint). We want to make scale manageable as kubernetes ingress allows multiple IPs in the ingress Address:

> kubectl get ingress
NAME      RULE          BACKEND   ADDRESS
test      -                        104.154.107.202, 104.154.107.203  // hosts ip addresses where Rancher LB instances are deployed
          foo.bar.com
          /foo           nginx-service:80

• Support for Stickiness policies
• Support for TCP Load balancer
• Possible integration with Route53 provider. LB service FQDN populated by Rancher Route53 service, will be propagated as an entry point for the ingress.