Porter

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What is Porter

Porter is an open source load balancer designed for bare metal Kubernetes clusters. It's implemented by physical switch, and uses BGP and ECMP to achieve the best performance and high availability.

Why Porter

As we know, In the cloud-hosted Kubernetes cluster, the cloud providers (AWS, GCP, Azure, etc.) usually provide the Load Balancer to assign IPs and expose the service to outside.

However, the service is hard to expose in a bare metal cluster since Kubernetes does not provide a load-balancer for bare metal environment. Fortunately, Porter allows you to create Kubernetes services of type "LoadBalancer" in bare metal clusters, which makes you have consistent experience with the cloud.

Core Features

Porter has two components which provide the following core features:

• LB Controller & Agent: The controller is responsible for synchronizing BGP routes to the physical switch; The agent is deployed to each node as DaemonSet to maintain the drainage rules;

• EIP service, including the EIP pool management and EIP controller, the controller is responsible for dynamically updating the EIP information of the service.

Note: Porter is a subproject of KubeSphere.

Principle

The following figure describes the principle of Porter. Assuming there is a distributed service deployed on node1 (192.168.0.2) and node2 (192.168.0.6). The service needs to be accessed through EIP 1.1.1.1. After deploying the Example Service, Porter will automatically synchronize routing information to the leaf switch, and then synchronize to the spine and border switch, thus external users can access the service through EIP 1.1.1.1.

Deployment Architecture

Porter serves as a Load-Balancer plugin, monitoring the changes of the service in the cluster through a Manager, and advertises related routes. At the same time, all the nodes in the cluster are deployed with an agent. Each time an EIP is used, a host routing rule will be added to the host, diverting the IP packets sent to the EIP to the local.

Logic

When Porter is deployed as a service in Kubernetes cluster, it establishes a BGP connection with the cluster's border router (Layer 3 switch). When a service with a specific annotation (e.g. lb.kubesphere.io/v1apha1: porter, see Example Service) has been created in the cluster, the service is dynamically assigned an EIP (users can also specify EIP by themselves). The LB controller creates a route and forwards the route to the public network (or private network) through BGP, so that the service can be accessed externally.

The Porter LB controller is a custom controller based on the Kubernetes controller runtime, which automatically update the routing information by watching changes of the service.

Installation

1. Deploy Porter on Bare Metal Kubernetes Cluster
2. Test Porter on QingCloud with a Simulate Router

Build

Prerequisites

1. Go 1.11, the plugin uses gobgp to create BGP client, and godgp requires Go 1.11.
2. Docker
3. Kustomize，it uses kustomize to dynamically generate the k8s yaml files needed for the cluster.
4. If you need to push the plugin image to the remote private repository, you need to execute docker login in advance.

Steps

1. Execute git clone https://github.com/kubesphere/porter.git, then enter into the folder.
2. Following with the above guides to modify the config.toml (Under config/bgp/).
3. (Optional）Modify the code according to your needs.
4. (Optional）Modify the parameters of the image according to your needs (Under config/manager).
5. (Optional）Follow the Simulation Tutorial to deploy a Bird node, then modify the BirdIP in hack/test.sh, and run make e2e-test for e2e testing.
6. Modify the IMG name in the Makefile, then run make release, and the final yaml file is under /deploy.
7. Execute kubectl apply -f deploy/release.yaml to deploy porter as a plugin.

License

Porter is licensed under the Apache License, Version 2.0. See LICENSE for the full license text.