Add ARM support and fix AMI resolution for Ubuntu (#4367)

Author: cPu1

integration/tests/managed/managed_nodegroup_test.go

@@ -118,7 +118,7 @@ var _ = Describe("(Integration) Create Managed Nodegroups", func() {
 			},
 		}),
 
-		PEntry("Ubuntu", &api.ManagedNodeGroup{
+		Entry("Ubuntu", &api.ManagedNodeGroup{
 			NodeGroupBase: &api.NodeGroupBase{
 				Name:       "ubuntu",
 				VolumeSize: aws.Int(25),

pkg/ami/auto_resolver.go

@@ -26,7 +26,8 @@ func MakeImageSearchPatterns(version string) map[string]map[int]string {
 			ImageClassARM:     fmt.Sprintf("amazon-eks-arm64-node-%s-*", version),
 		},
 		api.NodeImageFamilyUbuntu2004: {
-			ImageClassGeneral: fmt.Sprintf("ubuntu-eks/k8s_%s/images/*20.04*", version),
+			ImageClassGeneral: fmt.Sprintf("ubuntu-eks/k8s_%s/images/*20.04-amd64*", version),
+			ImageClassARM:     fmt.Sprintf("ubuntu-eks/k8s_%s/images/*20.04-arm64*", version),
 		},
 		api.NodeImageFamilyUbuntu1804: {
 			ImageClassGeneral: fmt.Sprintf("ubuntu-eks/k8s_%s/images/*18.04*", version),