How to create nginx ingress in terraform - aks

You could try using Terraform's helm provider.

provider "helm" {
    kubernetes {
        host     = azurerm_kubernetes_cluster.your_cluster.kube_config.0.host
        client_key             = base64decode(azurerm_kubernetes_cluster.your_cluster.kube_config.0.client_key)
        client_certificate     = base64decode(azurerm_kubernetes_cluster.your_cluster.kube_config.0.client_certificate)
        cluster_ca_certificate = base64decode(azurerm_kubernetes_cluster.your_cluster.kube_config.0.cluster_ca_certificate)
    }  
}

data "helm_repository" "stable" {
  name = "stable"
  url  = "https://kubernetes-charts.storage.googleapis.com"
}

resource "helm_release" "nginix_ingress" {
    name      = "nginx_ingress"
    repository = data.helm_repository.stable.metadata.0.name
    chart     = "stable/nginx-ingress"
    namespace = "kube-system"
}

If your cluster is already created, you will have to import it as well using a data source. helm_release also supports custom values. Here is the link if you need more information.

There is a nice tutorial Create an Application Gateway ingress controller in Azure Kubernetes Service. And you can check GitHub for Application Gateway Ingress Controller.

If you are using Terraform version 0.12 or higher you can use terraform provider kubernetes example.

As for the Terraform documentation you should check Data source kubernetes_ingress and Resource kubernetes_ingress.

If you provide more details I'll update the answer.

Updated answer

resource "helm_release" "nginix-ingress" {
  name      = "nginix-ingress"    
  repository = "https://charts.bitnami.com/bitnami"    
  chart     = "nginx"
  namespace = "kube-system"
}

I offer an alternative, in my opinion better, way to provision Kubernetes services like Nginx ingress using Terraform.

My kustomize based modules have two main benefits over using helm based modules:

1. Patching instead of templating makes maintaining custom configuration easier across new upstream versions
2. My kustomization provider, unlike the helm provider, shows detailed diffs and even destroy/recreate during terraform plan

If you're interested, here's a detailed comparison between my kustomize based Nginx ingress Terraform module and a helm based module.

Using the module is straight forward:

# require and configure provider
terraform {
  required_providers {
    kustomization = {
      source = "kbst/kustomization"
    }
  }
}

provider "kustomization" {
  alias = "example"

  kubeconfig_path = "~/.kube/config"
}

# call module
module "example_nginx" {
  providers = {
    # we're using the alias provider we configured above
    kustomization = kustomization.example
  }

  source  = "kbst.xyz/catalog/nginx/kustomization"
  version = "1.2.1-kbst.0" # find the latest version on https://www.kubestack.com/catalog/nginx

  # the configuration here assumes you're using Terraform's default workspace
  # use `terraform workspace list` to see the workspaces
  configuration_base_key = "default"
  configuration = {
    default = {
      replicas = [{
        name  = "ingress-nginx-controller"
        count = 5
      }]
    }
  }
}

The example module call uses kustomize's replicas attribute to change the replicas of the Nginx ingress controller.

The module's (I have them for more than just Nginx) allow defining the kustomization as part of the module call. They also bundle an upstream release, and you control the version using the version attribute.

Documentation for all available kustomization attributes can be found on the Kubestack website.

I maintain these modules as part of Kubestack, my open-source framework for platform teams working with Terraform and Kubernetes.