By default the ingress-nginx controller has service interruptions whenever it's pods are restarted or redeployed. In order to fix that, see the excellent blog post by Lindsay Landry from Codecademy: [Kubernetes: Nginx and Zero Downtime in Production](https://medium.com/codecademy-engineering/kubernetes-nginx-and-zero-downtime-in-production-2c910c6a5ed8).
1. For Nginx Ingress controllers used for non-critical services, the easiest method is to [uninstall](#uninstall-chart) the old release and [install](#install-chart) the new one
1. For critical services in production that require zero-downtime, you will want to:
1. [Install](#install-chart) a second Ingress controller
1. Redirect your DNS traffic from the old controller to the new controller
1. Log traffic from both controllers during this changeover
1. [Uninstall](#uninstall-chart) the old controller once traffic has fully drained from it
Note that there are some different and upgraded configurations between the two charts, described by Rimas Mocevicius from JFrog in the "Upgrading to ingress-nginx Helm chart" section of [Migrating from Helm chart nginx-ingress to ingress-nginx](https://rimusz.net/migrating-to-ingress-nginx). As the `ingress-nginx/ingress-nginx` chart continues to update, you will want to check current differences by running [helm configuration](#configuration) commands on both charts.
## Configuration
See [Customizing the Chart Before Installing](https://helm.sh/docs/intro/using_helm/#customizing-the-chart-before-installing). To see all configurable options with detailed comments:
You can add Prometheus annotations to the metrics service using `controller.metrics.service.annotations`. Alternatively, if you use the Prometheus Operator, you can enable ServiceMonitor creation using `controller.metrics.serviceMonitor.enabled`.
Previous versions of this chart had a `controller.stats.*` configuration block, which is now obsolete due to the following changes in nginx ingress controller:
* in [0.16.1](https://github.com/kubernetes/ingress-nginx/blob/master/Changelog.md#0161), the vts (virtual host traffic status) dashboard was removed
* in [0.23.0](https://github.com/kubernetes/ingress-nginx/blob/master/Changelog.md#0230), the status page at port 18080 is now a unix socket webserver only available at localhost.
You can use `curl --unix-socket /tmp/nginx-status-server.sock http://localhost/nginx_status` inside the controller container to access it locally, or use the snippet from [nginx-ingress changelog](https://github.com/kubernetes/ingress-nginx/blob/master/Changelog.md#0230) to re-enable the http server
Annotate the controller as shown in the [nginx-ingress l7 patch](https://github.com/kubernetes/ingress-nginx/blob/master/deploy/aws/l7/service-l7.yaml):
To configure the LoadBalancer service with the [route53-mapper addon](https://github.com/kubernetes/kops/tree/master/addons/route53-mapper), add the `domainName` annotation and `dns` label:
This setup is useful when you need both external and internal load balancers but don't want to have multiple ingress controllers and multiple ingress objects per application.
By default, the ingress object will point to the external load balancer address, but if correctly configured, you can make use of the internal one if the URL you are looking up resolves to the internal load balancer's URL.
You'll need to set both the following values:
`controller.service.internal.enabled`
`controller.service.internal.annotations`
If one of them is missing the internal load balancer will not be deployed. Example you may have `controller.service.internal.enabled=true` but no annotations set, in this case no action will be taken.
`controller.service.internal.annotations` varies with the cloud service you're using.
An use case for this scenario is having a split-view DNS setup where the public zone CNAME records point to the external balancer URL while the private zone CNAME records point to the internal balancer URL. This way, you only need one ingress kubernetes object.
With nginx-ingress-controller version 0.25+, the nginx ingress controller pod exposes an endpoint that will integrate with the `validatingwebhookconfiguration` Kubernetes feature to prevent bad ingress from being added to the cluster.
If you are upgrading this chart from a version between 0.31.0 and 1.2.2 then you may get an error like this:
```
Error: UPGRADE FAILED: Service "?????-controller" is invalid: spec.clusterIP: Invalid value: "": field is immutable
```
Detail of how and why are in [this issue](https://github.com/helm/charts/pull/13646) but to resolve this you can set `xxxx.service.omitClusterIP` to `true` where `xxxx` is the service referenced in the error.
As of version `1.26.0` of this chart, by simply not providing any clusterIP value, `invalid: spec.clusterIP: Invalid value: "": field is immutable` will no longer occur since `clusterIP: ""` will not be rendered.