High Availability and Load-Balancing
Kubernetes Virtual IP and Load-Balancer for both control plane and Kubernetes services
The idea behind kube-vip is a small self-contained Highly-Available option for all environments, especially:
- Bare-Metal
- Edge (arm / Raspberry PI)
- Virtualisation
- Pretty much anywhere else :)
NOTE: All documentation of both usage and architecture are now available at https://kube-vip.io.
Kube-Vip was originally created to provide a HA solution for the Kubernetes control plane, over time it has evolved to incorporate that same functionality into Kubernetes service type load-balancers.
- VIP addresses can be both IPv4 or IPv6
- Control Plane with ARP (Layer 2) or BGP (Layer 3)
- Control Plane using either leader election or raft
- Control Plane HA with kubeadm (static Pods)
- Control Plane HA with K3s/and others (daemonsets)
- Service LoadBalancer using leader election for ARP (Layer 2)
- Service LoadBalancer using multiple nodes with BGP
- Service LoadBalancer address pools per namespace or global
- Service LoadBalancer address via (existing network DHCP)
- Service LoadBalancer address exposure to gateway via UPNP
- ... manifest generation, vendor API integrations and many nore...
The purpose of kube-vip is to simplify the building of HA Kubernetes clusters, which at this time can involve a few components and configurations that all need to be managed. This was blogged about in detail by thebsdbox here -> https://thebsdbox.co.uk/2020/01/02/Designing-Building-HA-bare-metal-Kubernetes-cluster/#Networking-load-balancing.
kube-vip provides both a floating or virtual IP address for your kubernetes cluster as well as load-balancing the incoming traffic to various control-plane replicas. At the current time to replicate this functionality a minimum of two pieces of tooling would be required:
VIP:
- Keepalived
- UCARP
- Hardware Load-balancer (functionality differs per vendor)
LoadBalancing:
All of these would require a separate level of configuration and in some infrastructures multiple teams in order to implement. Also when considering the software components, they may require packaging into containers or if they’re pre-packaged then security and transparency may be an issue. Finally, in edge environments we may have limited room for hardware (no HW load-balancer) or packages solutions in the correct architectures might not exist (e.g. ARM). Luckily with kube-vip being written in GO, it’s small(ish) and easy to build for multiple architectures, with the added security benefit of being the only thing needed in the container.
Please raise issues on the GitHub repository and as mentioned check the documentation at https://kube-vip.io.