feat: added mixed cluster mode (#1042)

* mixed mode implementation

* fixed typo on 24.04 Ubuntu Minimal version

Author: alcampag

modules/workers/locals.tf

@@ -298,16 +298,16 @@ locals {
     "22.04"         = "jammy"
     "24.04"         = "noble"
     "22.04 Minimal" = "jammy"
-    "24.04 Minimal" = "nobble"
+    "24.04 Minimal" = "noble"
   }
 
   ubuntu_worker_pools = {
     for k, v in local.enabled_worker_pools : k => {
       kubernetes_major_version = substr(lookup(v, "kubernetes_version", ""), 1, 4)
       kubernetes_minor_version = substr(lookup(v, "kubernetes_version", ""), 1, -1)
-      ubuntu_release           = lookup(data.oci_core_image.workers[k], "operating_system_version", null) != null ? lookup(data.oci_core_image.workers[k], "operating_system_version") : lookup(v, "os_version", null)
+      ubuntu_release           = lookup(lookup(data.oci_core_image.workers, k, {}), "operating_system_version", null) != null ? lookup(lookup(data.oci_core_image.workers, k, {}), "operating_system_version") : lookup(v, "os_version", null)
     }
     if lookup(v, "mode", var.worker_pool_mode) != "virtual-node-pool" &&
-    contains(coalescelist(split(" ", lookup(data.oci_core_image.workers[k], "operating_system", "")), [lookup(v, "os", "")]), "Ubuntu")
+    contains(coalescelist(split(" ", lookup(lookup(data.oci_core_image.workers, k, {}), "operating_system", "")), [lookup(v, "os", "")]), "Ubuntu")
   }
 }

modules/workers/virtualnodepools.tf

@@ -80,16 +80,8 @@ resource "oci_containerengine_virtual_node_pool" "workers" {
     }
 
     precondition {
-      condition     = contains(["Pod.Standard.E3.Flex", "Pod.Standard.E4.Flex"], each.value.shape)
-      error_message = "Virtual Node Pools must be 'Pod.Standard.E3.Flex' or 'Pod.Standard.E4.Flex'."
-    }
-
-    precondition {
-      condition = length(local.enabled_modes) == 1
-      error_message = format(
-        "Mixed mode cluster is not allowed: %#v. Virtual and provisioned node pools cannot be created in the same cluster.",
-        local.enabled_modes
-      )
+      condition     = contains(["Pod.Standard.E3.Flex", "Pod.Standard.E4.Flex", "Pod.Standard.A1.Flex"], each.value.shape)
+      error_message = "Virtual Node Pools must be 'Pod.Standard.E3.Flex', 'Pod.Standard.E4.Flex' or 'Pod.Standard.A1.Flex'."
     }
   }
 }