kube-openresty-ingress

Kubernetes Ingress using Lua in Openresty.

kube-openresty-ingress implements an ingress controller for Kubernetes. It acts as both a controller and the load-balancer. It should be ran as a replication controller. It needs to be exposed via a service.

Based on https://github.com/kubernetes/contrib/tree/master/Ingress/controllers/nginx-alpha

Building

Use the included Dockerfile to build an image. kube-openresty-ingress.json can be used as an example for creating the Kubernetes resources.

Features and Limitations

• Can be used as a namespace specific or a global load balancer.
• Can be limited to certain ingresses using a labelSelector
• Multiple ingresses per controller by default.
• Does not support a default target for an ingress. Use / as the path to catch all unspecified traffic.
• Uses DNS for service lookups allowing the ingress to be created before the services.

Configuration

The included start script attempts to read the nameservers from /etc/resolv.conf inside the container.

Environment variables:

• NAMESPACE - limit ingress to a specific namespace. Defaults to global.
• CLUSTER_DOMAIN - domain for cluster DNS. defaults to cluster.local
• LABEL_SELECTOR - label selector for fetching ingresses. No default.

TODO

• Handle default ingress target
• Fetch service address using Kubernetes API rather than DNS. Errors with DNS even when using caching.

LICENSE

See LICENSE

Includes a vendored copy of:

• https://github.com/pintsized/lua-resty-http
• https://github.com/hamishforbes/lua-resty-dns-cache

Authors

Written by the Engineering Team at Yik Yak