Vault provider - illegal token_reviewer_jwt data

Terraform
1

Hello,

I am using the Vault provider for Terraform to enable Kubernetes auth for Vault.

resource "vault_auth_backend" "kubernetes" {
  type = "kubernetes"
}

resource "vault_kubernetes_auth_backend_config" "kubernetes" {
  backend            = vault_auth_backend.kubernetes.path
  kubernetes_host    = var.kubernetes_host
  kubernetes_ca_cert = var.kubernetes_ca_cert
  token_reviewer_jwt = var.token_reviewer_jwt
}

I followed the documentation at https://www.vaultproject.io/docs/platform/k8s/helm/examples/kubernetes-auth to obtain the token_reviewer_jwt and kubernetes_ca_cert.

However running terraform apply, the token_reviewer_jwt errors out with

 Error: error updating Kubernetes auth backend config "auth/kubernetes/config": Error making API request.
 URL: PUT [MASKED]/v1/auth/kubernetes/config
 Code: 500. Errors:
 * 1 error occurred:
 	* illegal base64 data at input byte 342
   on dev/main.tf line 33, in resource "vault_kubernetes_auth_backend_config" "kubernetes":
   33: resource "vault_kubernetes_auth_backend_config" "kubernetes" {

My token_reviewer_jwt variable is what was outputted from cat /var/run/secrets/kubernetes.io/serviceaccount/token.

I’ve also tried encoding the token_reviewer_jwt to base64encoded. but terraform apply errors with

 Error: error updating Kubernetes auth backend config "auth/kubernetes/config": Error making API request.
 URL: PUT [MASKED]/v1/auth/kubernetes/config
 Code: 500. Errors:
 * 1 error occurred:
 	* not a compact JWS
   on dev/main.tf line 33, in resource "vault_kubernetes_auth_backend_config" "kubernetes":
   33: resource "vault_kubernetes_auth_backend_config" "kubernetes" {
 ERROR: Job failed: command terminated with exit code 1