azurerm_kubernetes_cluster: remove unused docker_bridge_cidr variable

[zioproto]

Is there an existing issue for this?

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Terraform Version

1.2.8

AzureRM Provider Version

3.18.0

Affected Resource(s)/Data Source(s)

azurerm_kubernetes_cluster

Terraform Configuration Files

resource "azurerm_kubernetes_cluster" "main" {
[..CUT..]
network_profile {
    network_plugin     = var.network_plugin
    dns_service_ip     = var.net_profile_dns_service_ip
    docker_bridge_cidr = var.net_profile_docker_bridge_cidr
    network_policy     = var.network_policy
    outbound_type      = var.net_profile_outbound_type
    pod_cidr           = var.net_profile_pod_cidr
    service_cidr       = var.net_profile_service_cidr
  }
[..CUT..]
}

This is a cleanup request

Since 2020 the default AKS runtime is containerd and not Docker
https://github.com/Azure/AKS/blob/master/CHANGELOG.md#release-2020-06-29

It is not possible anymore to create an AKS cluster with Docker runtime.
https://docs.microsoft.com/en-us/azure/aks/cluster-configuration#container-runtime-configuration
Docker is no longer supported as of September 2022

However users of the resource azurerm_kubernetes_cluster are forced to set a value for docker_bridge_cidr because otherwise they cannot set service_cidr:

https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/kubernetes_cluster#docker_bridge_cidr

This is super confusing to have this technical debt for folks that start using this resource in 2022, and they have no idea why a Docker cidr is needed when Docker is not even used.

References

• https://github.com/Azure/AKS/blob/master/CHANGELOG.md#release-2020-06-29
• [Breaking] Remove unused net_profile_docker_bridge_cidr Azure/terraform-azurerm-aks#222

[zioproto]

Hello Folks, all AKS users are receiving this communication. This should be fixed in the provider as soon as possible. It should be possible to do not set docker_bridge_cidr and make this independent from service_cidr.

[github-actions]

This functionality has been released in v3.49.0 of the Terraform Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!