Merge Ingress Controller
Merge Ingress Controller combines multiple ingress resources into a new one.
Motivation
Different ingress controllers behave differently when creating services/load balancers satisfying the ingress resources of the managed class. Some create single service/LB for all ingress resources, some merge resources according to hosts or TLS certificates, other create separate service/LB per ingress resource.
E.g. AWS ALB Ingress Controller creates a new load balancer for each ingress resource. This can become quite costly. There is an issue to support reusing ALBs across ingress resources, however, it won't be implemented anytime soon.
Merge Ingress Controller allows you to create ingress resources that will be combined together to create a new ingress resource that will be managed by different controller.
Setup
Install via Helm:
helm install --namespace kube-system --name ingress-merge ./helmExample
Create multiple ingresses & one config map that will provide parameters for the result ingress:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: foo-ingress
annotations:
kubernetes.io/ingress.class: merge
merge.ingress.kubernetes.io/config: merged-ingress
spec:
rules:
- host: foo.example.com
http:
paths:
- path: /
backend:
serviceName: foo-svc
servicePort: 80
---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: bar-ingress
annotations:
kubernetes.io/ingress.class: merge
merge.ingress.kubernetes.io/config: merged-ingress
spec:
rules:
- host: bar.example.com
http:
paths:
- path: /
backend:
serviceName: bar-svc
servicePort: 80
---
apiVersion: v1
kind: ConfigMap
metadata:
name: merged-ingress
data:
annotations: |
kubernetes.io/ingress.class: otherMerge Ingress Controller will create new ingress resource named by the config map with rules combined together:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: merged-ingress
annotations:
kubernetes.io/ingress.class: other
spec:
rules:
- host: bar.example.com
http:
paths:
- path: /
backend:
serviceName: bar-svc
servicePort: 80
- host: foo.example.com
http:
paths:
- path: /
backend:
serviceName: foo-svc
servicePort: 80Annotations
| Annotation | Default Value | Description | Example |
|---|---|---|---|
kubernetes.io/ingress.class |
Use merge for this controller to take over. |
kubernetes.io/ingress.class: merge |
|
merge.ingress.kubernetes.io/config |
Name of the ConfigMap resource that will be used to merge this ingress with others. Because ingresses do not support to reference services across namespaces, neither does this reference. All ingresses to be merged, the config map & the result ingress use the same namespace. |
merge.ingress.kubernetes.io/config: merged-ingress |
|
merge.ingress.kubernetes.io/priority |
0 |
Rules from ingresses with higher priority come in the result ingress rules first. | merge.ingress.kubernetes.io/priority: 10 |
merge.ingress.kubernetes.io/result |
Marks ingress created by the controller. If all source ingress resources are deleted, this ingress is deleted as well. | merge.ingress.kubernetes.io/result: "true" |
Configuration keys
| Key | Default Value | Description | Example |
|---|---|---|---|
name |
name of the ConfigMap |
Name of the result ingress resource. | name: my-merged-ingress |
labels |
YAML/JSON-serialized labels to be applied to the result ingress. | labels: '{"app": "loadbalancer", "env": "prod"}' |
|
annotations |
{"merge.ingress.kubernetes.io/result":"true"} |
YAML/JSON-serialized labels to be applied to the result ingress. merge.ingress.kubernetes.io/result with value true will be always added to the annotations. |
annotations: '{"kubernetes.io/ingress.class": "alb"} |
backend |
Default backend for the result ingress (spec.backend). Source ingresses must not specify default backend (such ingresses won't be merged). |
backend: '{"serviceName": "default-backend-svc", "servicePort": 80} |
License
Licensed under MIT license. See LICENSE file.
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