chore: choose correct installation method for fleeting plugin (#1276)

## Description

The fleeting plugin installation method depends on the version of the
Runner used and can be automated starting with version 16.11 of the
Runner. See
https://docs.gitlab.com/runner/fleet_scaling/fleeting/#install-a-fleeting-plugin

Related to #1260

Author: julian-perge

main.tf

@@ -38,6 +38,15 @@ locals {
       extra_config        = var.runner_install.start_script
   })
 
+  # "16.0.3" -> ["16", "0", "3"]
+  runner_version_split = split(".", var.runner_gitlab.runner_version)
+  # ["16", "0", "3"] -> 16
+  runner_version_major = parseint(local.runner_version_split[0], 10)
+  # ["16", "0", "3"] -> 0
+  runner_version_minor = parseint(local.runner_version_split[1], 10)
+  # the `gitlab-runner fleeting install` command was introduced in 16.11
+  runner_use_new_fleeting_install = (local.runner_version_major == 16 && local.runner_version_minor >= 11) || local.runner_version_major > 16
+
   file_yum_update = file("${path.module}/template/yum_update.tftpl")
 
   template_eip = templatefile("${path.module}/template/eip.tftpl", {
@@ -80,13 +89,15 @@ locals {
       public_key                                                   = var.runner_worker.use_private_key && var.runner_worker.type == "docker-autoscaler" ? tls_private_key.autoscaler[0].public_key_openssh : var.runner_worker_docker_machine_fleet.enable == true ? tls_private_key.fleet[0].public_key_openssh : ""
       private_key                                                  = var.runner_worker.use_private_key && var.runner_worker.type == "docker-autoscaler" ? tls_private_key.autoscaler[0].private_key_pem : var.runner_worker_docker_machine_fleet.enable == true ? tls_private_key.fleet[0].private_key_pem : ""
       use_private_key                                              = var.runner_worker_docker_machine_fleet.enable || (var.runner_worker.use_private_key && var.runner_worker.type == "docker-autoscaler")
+      use_new_fleeting_install                                     = local.runner_use_new_fleeting_install
       use_new_runner_authentication_gitlab_16                      = var.runner_gitlab_registration_config.type != ""
       user_data_trace_log                                          = var.debug.trace_runner_user_data
       fleeting_plugin_version                                      = var.runner_worker_docker_autoscaler.fleeting_plugin_version
   })
 
   template_runner_docker_autoscaler = templatefile("${path.module}/template/runner-docker-autoscaler-config.tftpl",
     {
+      fleeting_plugin               = local.runner_use_new_fleeting_install ? "aws:latest" : "fleeting-plugin-aws"
       docker_autoscaling_name       = var.runner_worker.type == "docker-autoscaler" ? aws_autoscaling_group.autoscaler[0].name : ""
       connector_config_user         = var.runner_worker_docker_autoscaler.connector_config_user
       runners_capacity_per_instance = var.runner_worker_docker_autoscaler.capacity_per_instance

template/gitlab-runner.tftpl

@@ -199,37 +199,38 @@ then
 fi
 
 if [[ "${runners_executor}" == "docker-autoscaler" ]]; then
-  echo "installing docker"
+  echo "Installing Docker by autoscaler"
   yum install docker -y
   usermod -a -G docker ec2-user
   service docker start
 
-  echo "Installing Docker fleeting plugin"
-  # Determine architecture
-  if [[ "$(uname -m)" == "x86_64" ]]; then
-    ARCH="amd64"
-  elif [[ "$(uname -m)" == "i686" ]]; then
-    ARCH="386"
-  elif [[ "$(uname -m)" == "armv7l" ]]; then
-    ARCH="arm"
-  elif [[ "$(uname -m)" == "aarch64" ]]; then
-    ARCH="arm64"
-  else
-    echo "Unsupported architecture"
-    exit 1
-  fi
+  if [[ "${use_new_fleeting_install}" == "false" ]]; then
+    # Determine architecture
+    if [[ "$(uname -m)" == "x86_64" ]]; then
+      ARCH="amd64"
+    elif [[ "$(uname -m)" == "i686" ]]; then
+      ARCH="386"
+    elif [[ "$(uname -m)" == "armv7l" ]]; then
+      ARCH="arm"
+    elif [[ "$(uname -m)" == "aarch64" ]]; then
+      ARCH="arm64"
+    else
+      echo "Unsupported architecture"
+      exit 1
+    fi
 
-  wget "https://gitlab.com/gitlab-org/fleeting/plugins/aws/-/releases/v${fleeting_plugin_version}/downloads/fleeting-plugin-aws-$(uname -s | tr '[:upper:]' '[:lower:]')-$ARCH"
-  chmod +x fleeting-plugin-aws-*
-  mv fleeting-plugin-aws-* /bin/fleeting-plugin-aws
+    echo "Installing Docker fleeting-plugin-aws manually"
+    wget "https://gitlab.com/gitlab-org/fleeting/plugins/aws/-/releases/v${fleeting_plugin_version}/downloads/fleeting-plugin-aws-$(uname -s | tr '[:upper:]' '[:lower:]')-$ARCH"
+    chmod +x fleeting-plugin-aws-*
+    mv fleeting-plugin-aws-* /bin/fleeting-plugin-aws
+  fi
 
   mkdir ~/.aws
   cat <<EOF > ~/.aws/config
 [default]
 region = "${aws_region}"
 
 EOF
-
 fi
 
 # A small script to remove this runner from being registered with Gitlab. Executed at shutdown.
@@ -297,6 +298,10 @@ if ! ( rpm -q gitlab-runner >/dev/null )
 then
   curl --fail --retry 6 -L https://packages.gitlab.com/install/repositories/runner/gitlab-runner/script.rpm.sh | bash
   yum install gitlab-runner-${gitlab_runner_version} -y
+  if [[ "${runners_executor}" == "docker-autoscaler" ]] && [[ "${use_new_fleeting_install}" == "true" ]]; then
+    echo "Installing gitlab-runner fleeting plugin"
+    gitlab-runner fleeting install
+  fi
 fi
 
 #############################

template/runner-docker-autoscaler-config.tftpl

@@ -1,6 +1,6 @@
 # Autoscaler config
   [runners.autoscaler]
-    plugin = "fleeting-plugin-aws"
+    plugin = "${fleeting_plugin}"
 
     capacity_per_instance = ${runners_capacity_per_instance}
     update_interval = "${runners_update_interval}"