Support custom Ubuntu AMIs for EKS-managed nodegroups (#6850)

* Add support for managed nodegroups with custom Ubuntu AMIs

* update docs

pkg/apis/eksctl.io/v1alpha5/validation.go

@@ -1207,8 +1207,8 @@ func ValidateManagedNodeGroup(index int, ng *ManagedNodeGroup) error {
 		if ng.AMIFamily == "" {
 			return errors.Errorf("when using a custom AMI, amiFamily needs to be explicitly set via config file or via --node-ami-family flag")
 		}
-		if ng.AMIFamily != NodeImageFamilyAmazonLinux2 {
-			return errors.Errorf("cannot set amiFamily to %s when using a custom AMI for managed nodes, only %s is supported", ng.AMIFamily, NodeImageFamilyAmazonLinux2)
+		if ng.AMIFamily != NodeImageFamilyAmazonLinux2 && ng.AMIFamily != NodeImageFamilyUbuntu1804 && ng.AMIFamily != NodeImageFamilyUbuntu2004 {
+			return errors.Errorf("cannot set amiFamily to %s when using a custom AMI for managed nodes, only %s, %s and %s are supported", ng.AMIFamily, NodeImageFamilyAmazonLinux2, NodeImageFamilyUbuntu1804, NodeImageFamilyUbuntu2004)
 		}
 		if ng.OverrideBootstrapCommand == nil {
 			return errors.Errorf("%s.overrideBootstrapCommand is required when using a custom AMI (%s.ami)", path, path)

pkg/apis/eksctl.io/v1alpha5/validation_test.go

@@ -1927,6 +1927,30 @@ var _ = Describe("ClusterConfig validation", func() {
 			Expect(err).To(MatchError("AMI Family SomeTrash is not supported - use one of: AmazonLinux2, Ubuntu2004, Ubuntu1804, Bottlerocket, WindowsServer2019CoreContainer, WindowsServer2019FullContainer, WindowsServer2022CoreContainer, WindowsServer2022FullContainer"))
 		})
 
+		It("fails when the AmiFamily is not supported for managed nodes with custom AMI", func() {
+			mng := api.NewManagedNodeGroup()
+			mng.AMI = "ami-1234"
+			mng.OverrideBootstrapCommand = aws.String("bootstrap command")
+
+			mng.AMIFamily = api.NodeImageFamilyAmazonLinux2
+			err := api.ValidateManagedNodeGroup(0, mng)
+			Expect(err).NotTo(HaveOccurred())
+
+			mng.AMIFamily = api.NodeImageFamilyUbuntu1804
+			err = api.ValidateManagedNodeGroup(0, mng)
+			Expect(err).NotTo(HaveOccurred())
+
+			mng.AMIFamily = api.NodeImageFamilyUbuntu2004
+			err = api.ValidateManagedNodeGroup(0, mng)
+			Expect(err).NotTo(HaveOccurred())
+
+			mng.AMIFamily = api.NodeImageFamilyBottlerocket
+			mng.OverrideBootstrapCommand = nil
+			err = api.ValidateManagedNodeGroup(0, mng)
+			errorMsg := fmt.Sprintf("cannot set amiFamily to %s when using a custom AMI for managed nodes, only %s, %s and %s are supported", mng.AMIFamily, api.NodeImageFamilyAmazonLinux2, api.NodeImageFamilyUbuntu1804, api.NodeImageFamilyUbuntu2004)
+			Expect(err).To(MatchError(errorMsg))
+		})
+
 		It("fails when the AMIFamily is WindowsServer2004CoreContainer", func() {
 			ng.AMIFamily = api.NodeImageFamilyWindowsServer2004CoreContainer
 			err := api.ValidateNodeGroup(0, ng, cfg)

userdocs/src/usage/custom-ami-support.md

@@ -30,12 +30,15 @@ Config file example:
 nodeGroups:
   - name: ng1
     instanceType: p2.xlarge
+    amiFamily: AmazonLinux2
     ami: auto
   - name: ng2
     instanceType: m5.large
+    amiFamily: AmazonLinux2
     ami: ami-custom1234
 managedNodeGroups:
   - name: m-ng-2
+    amiFamily: AmazonLinux2
     ami: ami-custom1234
     instanceType: m5.large
     overrideBootstrapCommand: |
@@ -79,6 +82,9 @@ managedNodeGroups:
 
 The `--node-ami-family` flag can also be used with `eksctl create nodegroup`. `eksctl` requires AMI Family to be explicitly set via config file or via `--node-ami-family` CLI flag, whenever working with a custom AMI.
 
+???+ note
+    At the moment, EKS managed nodegroups only support the following AMI Families when working with custom AMIs: `AmazonLinux2`, `Ubuntu1804` and `Ubuntu2004`
+
 ## Windows custom AMI support
 Only self-managed Windows nodegroups can specify a custom AMI. `amiFamily` should be set to a valid Windows AMI family.