vingress

Synopsis

This Helm chart installs an Ingress Controller based on Varnish Cache.

---

Table of contents

• Installation
• Usage
• Configuration
• Add custom behaviour with VCL

---

Installation

Connect to a Kubernetes cluster and run the following:

Add this repository to your Helm:

$ helm repo add varnish-ingress-controller https://mariusmagureanu.github.io/vingress/charts

Install the Chart:

$ helm install vingress --create-namespace -n varnish-ingress  varnish-ingress-controller/varnish-ingress-controller

---

Usage

Update the spec of your Ingress(es) with the following requirements:

1. Add the following label: kubernetes.io/ingress: varnish
2. Set the ingress class: spec.ingressClassName: varnish

The Varnish Ingress controller watches only over Ingress objects which meet both of the conditions mentioned above.

Example:

The following Ingress spec:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  generation: 4
  labels:
    kubernetes.io/ingress: varnish
  name: media
  namespace: demo
  resourceVersion: "146788664"
  uid: b386a268-0006-446c-9844-3e004712070f
spec:
  ingressClassName: varnish
  rules:
  - host: foo.bar.com
    http:
      paths:
      - backend:
          service:
            name: media-v1-svc
            port:
              number: 80
        path: /foo
        pathType: Prefix
  - host: qux.bar.com
    http:
      paths:
      - backend:
          service:
            name: media-v2-svc
            port:
              number: 80
        path: /qux
        pathType: Exact

yields the following VCL:

vcl 4.1;

import directors;
import std;

backend default none;

backend demo-media-media-v1-svc {
  .host = "media-v1-svc.demo.svc.cluster.local";
  .port = "80";
}
  
backend demo-media-media-v2-svc {
  .host = "media-v2-svc.demo.svc.cluster.local";
  .port = "80";
}
  

sub vcl_recv {
 if (req.http.host == "foo.bar.com" && req.url ~ "^/foo") {
        set req.backend_hint = demo-media-media-v1-svc;
    }
 if (req.http.host == "qux.bar.com" && req.url == "/qux") {
        set req.backend_hint = demo-media-media-v2-svc;
    }
}

---

Configuration

The Helm chart comes along with pretty much sane defaults. However, depending on the use case - the resource requests and/or limits need to be tweaked accordingly.

Snippet from a values.yaml file:

resources:
  requests:
    memory: "4096Mi"
    cpu: "250m"
  limits:
    memory: "4096Mi"
    cpu: "1"

Pass any parameters to varnish using a similar snippet like the one below.

Snippet from a values.yaml file:

varnish:
  httpPort: "6081"
  vclFile: "/etc/varnish/default.vcl"
  workFolder: "/etc/varnish"
  params: "-p thread_pool_min=5 -p thread_pool_max=500 -p thread_pool_timeout=300"
  defaultTtl: "240s"

---

Add custom behaviour with VCL

By default, the Ingress controller translates the Ingress spec into VCL. This translation results with the creation of Varnish backends and the generation of the vcl_recv subroutine.

In order to extend the generated VCL, use the varnish-vcl Configmap found in the namespace where the Ingress controller is installed.

The mentioned Configmap exposes two fields as follows:

• vcl_recv_snippet: snippet added in the vcl_recv subroutine after the backends selection
• snippet: snippet added after the vcl_rec subroutine

Example:

$ kubectl -n varnish-ingress get cm/varnish-vcl -o yaml

apiVersion: v1
kind: ConfigMap
metadata:
  annotations:
    meta.helm.sh/release-name: varnish-ingress-controller
    meta.helm.sh/release-namespace: varnish-ingress
  labels:
    app.kubernetes.io/managed-by: Helm
  name: varnish-vcl
  namespace: varnish-ingress
  resourceVersion: "154768231"
data:
  vcl_recv_snippet: |
    if (! req.backend_hint) {
      return (synth(200, "We're here now!"));
    }
  snippet: |
    sub vcl_backend_response {
      if (beresp.status == 200) {
          set beresp.ttl = 5m; 
      }
      unset beresp.http.Cache-Control;
    }

    sub vcl_deliver {
      if (obj.hits > 0) {
          set resp.http.X-Cache = "HIT"; 
      } else {
          set resp.http.X-Cache = "MISS";
      }
      set resp.http.X-Varnish = "X-Varnish-Foo";
    }

The snippet must contain valid VCL, otherwise it will fail against Varnish’s compilation.

Varnish will automatically have its VCL reloaded everytime either Ingress objects or the varnish-vcl Configmap have been altered.