stackit: add k8s api load balancer (#2925)

terraform/infrastructure/openstack/modules/stackit_loadbalancer/main.tf

@@ -0,0 +1,47 @@
+terraform {
+  required_providers {
+    stackit = {
+      source  = "stackitcloud/stackit"
+      version = "0.12.0"
+    }
+  }
+}
+
+resource "stackit_loadbalancer" "loadbalancer" {
+  project_id = var.stackit_project_id
+  name       = "${var.name}-lb"
+  target_pools = [
+    for portName, port in var.ports : {
+      name        = "target-pool-${portName}"
+      target_port = port
+      targets = [
+        for ip in var.member_ips : {
+          display_name = "target-${portName}"
+          ip           = ip
+        }
+      ]
+      active_health_check = {
+        healthy_threshold   = 10
+        interval            = "3s"
+        interval_jitter     = "3s"
+        timeout             = "3s"
+        unhealthy_threshold = 10
+      }
+    }
+  ]
+  listeners = [
+    for portName, port in var.ports : {
+      name        = "listener-${portName}"
+      port        = port
+      protocol    = "PROTOCOL_TCP"
+      target_pool = "target-pool-${portName}"
+    }
+  ]
+  networks = [
+    {
+      network_id = var.network_id
+      role       = "ROLE_LISTENERS_AND_TARGETS"
+    }
+  ]
+  external_address = var.external_address
+}