Skip to content

Terraform Provider for Kubernetes authenticate with `oidc-login`

What

If you use the oidc-login tool to authenticate to your cluster, you may have issues when it comes to using the terraform provider for Kubernetes. This boils down to not wanting to use the root certificates

How

Firstly, copy the value of certificate-authority-data under your kubeconfig for the cluster you want to use

apiVersion: v1
clusters:
  - cluster:
      certificate-authority-data: ""

Terraform config

  1. Update cluster_ca_certificate to be the copy and pasted from the above. Ensure this is base64 decoded. You can also use a variable or file
  2. Update oidc-issuer-url to the issuer of your oidc issuer.
  3. Update oidc-client-id to the OIDC client ID from your OIDC issuer
  4. Update oidc-client-secret to the Secret from your OIDC issuer

Depending on your issuer and how you've configured your cluster, you may want to add as many or as little oidc-extra-scope's

provider "kubernetes" {
  host                   = "https://172.16.2.0:6443"
  cluster_ca_certificate = base64decode("")
  exec {
    api_version = "client.authentication.k8s.io/v1beta1"
    command = "kubectl"
    args = [
      "oidc-login",
      "get-token",
      "--oidc-issuer-url=<>/",
      "--oidc-client-id=<>",
      "--oidc-client-secret=<>",
      "--oidc-extra-scope=groups",
      "--oidc-extra-scope=email",
    ]
  }
}
Example using Azure AD (Entra) 
provider "kubernetes" {
  host                   = "https://172.16.2.0:6443"
  cluster_ca_certificate = base64decode("<redacted>")
  exec {
    api_version = "client.authentication.k8s.io/v1beta1"
    command = "kubectl"
    args = [
      "oidc-login",
      "get-token",
      "--oidc-issuer-url=https://sts.windows.net/87be2c44-88cf-4eee-84a6-f2f47f2e8131/",
      "--oidc-client-id=36c6496f-3b53-4fea-bbfb-b4a69cccc646",
      "--oidc-client-secret=OAH8Q~tDUjHJK7iubJs16SfBupt2cJiPGZjosd8IVa32",
      "--oidc-extra-scope=groups",
      "--oidc-extra-scope=email",
    ]
  }
}

Additional Reading

Want to make this site better? Open a PR, help fund hosting costs or message me on Matrix