improvement: update the wait_for_cluster_cmd logic to use curl if wget doesn't exist

README.md

@@ -25,9 +25,9 @@ You also need to ensure your applications and add ons are updated, or workloads
 
 An example of harming update was the removal of several commonly used, but deprecated  APIs, in Kubernetes 1.16. More information on the API removals, see the [Kubernetes blog post](https://kubernetes.io/blog/2019/07/18/api-deprecations-in-1-16/).
 
-By default, this module manage the `aws-auth` configmap for you (`manage_aws_auth=true`). To avoid the following [issue](https://github.com/aws/containers-roadmap/issues/654) where the EKS creation is `ACTIVE` but not ready, we implemented a retry logic with an `local-exec` provisioner and `wget` (by default).
+By default, this module manage the `aws-auth` configmap for you (`manage_aws_auth=true`). To avoid the following [issue](https://github.com/aws/containers-roadmap/issues/654) where the EKS creation is `ACTIVE` but not ready, we implemented a retry logic with an `local-exec` provisioner and `wget` (by default) with failover to `curl`.
 
-**If you want to manage your `aws-auth` configmap, ensure you have `wget` and `/bin/sh` installed where you're running Terraform or set `wait_for_cluster_cmd` and `wait_for_cluster_interpreter` to match your needs.**
+**If you want to manage your `aws-auth` configmap, ensure you have `wget` (or `curl`) and `/bin/sh` installed where you're running Terraform or set `wait_for_cluster_cmd` and `wait_for_cluster_interpreter` to match your needs.**
 
 For windows users, please read the following [doc](https://github.com/terraform-aws-modules/terraform-aws-eks/blob/master/docs/faq.md#deploying-from-windows-binsh-file-does-not-exist).
 
@@ -206,7 +206,7 @@ MIT Licensed. See [LICENSE](https://github.com/terraform-aws-modules/terraform-a
 | subnets | A list of subnets to place the EKS cluster and workers within. | `list(string)` | n/a | yes |
 | tags | A map of tags to add to all resources. | `map(string)` | `{}` | no |
 | vpc\_id | VPC where the cluster and workers will be deployed. | `string` | n/a | yes |
-| wait\_for\_cluster\_cmd | Custom local-exec command to execute for determining if the eks cluster is healthy. Cluster endpoint will be available as an environment variable called ENDPOINT | `string` | `"for i in `seq 1 60`; do wget --no-check-certificate -O - -q $ENDPOINT/healthz >/dev/null && exit 0 || true; sleep 5; done; echo TIMEOUT && exit 1"` | no |
+| wait\_for\_cluster\_cmd | Custom local-exec command to execute for determining if the eks cluster is healthy. Cluster endpoint will be available as an environment variable called ENDPOINT | `string` | `"for i in `seq 1 60`; do if `command -v wget > /dev/null`; then wget --no-check-certificate -O - -q $ENDPOINT/healthz >/dev/null && exit 0 || true; else curl -k -s $ENDPOINT/healthz >/dev/null && exit 0 || true;fi; sleep 5; done; echo TIMEOUT && exit 1"` | no |
 | wait\_for\_cluster\_interpreter | Custom local-exec command line interpreter for the command to determining if the eks cluster is healthy. | `list(string)` | <pre>[<br>  "/bin/sh",<br>  "-c"<br>]</pre> | no |
 | worker\_additional\_security\_group\_ids | A list of additional security group ids to attach to worker instances | `list(string)` | `[]` | no |
 | worker\_ami\_name\_filter | Name filter for AWS EKS worker AMI. If not provided, the latest official AMI for the specified 'cluster\_version' is used. | `string` | `""` | no |

variables.tf

@@ -200,7 +200,7 @@ variable "cluster_delete_timeout" {
 variable "wait_for_cluster_cmd" {
   description = "Custom local-exec command to execute for determining if the eks cluster is healthy. Cluster endpoint will be available as an environment variable called ENDPOINT"
   type        = string
-  default     = "for i in `seq 1 60`; do wget --no-check-certificate -O - -q $ENDPOINT/healthz >/dev/null && exit 0 || true; sleep 5; done; echo TIMEOUT && exit 1"
+  default     = "for i in `seq 1 60`; do if `command -v wget > /dev/null`; then wget --no-check-certificate -O - -q $ENDPOINT/healthz >/dev/null && exit 0 || true; else curl -k -s $ENDPOINT/healthz >/dev/null && exit 0 || true;fi; sleep 5; done; echo TIMEOUT && exit 1"
 }
 
 variable "wait_for_cluster_interpreter" {