fix(nodeup): set MACAddressPolicy to none when using AWS CNI and …

…Ubuntu 22.04

nodeup/pkg/model/sysctls.go

@@ -19,8 +19,10 @@ package model
 import (
 	"fmt"
 	"net"
+	"os"
 	"strings"
 
+	"k8s.io/klog/v2"
 	"k8s.io/kops/pkg/apis/kops"
 	"k8s.io/kops/upup/pkg/fi"
 	"k8s.io/kops/upup/pkg/fi/nodeup/nodetasks"
@@ -195,5 +197,38 @@ func (b *SysctlBuilder) Build(c *fi.NodeupModelBuilderContext) error {
 		OnChangeExecute: [][]string{{"sysctl", "--system"}},
 	})
 
+	// Running AWS VPC CNI on Ubuntu 22.04 Requires Setting MACAddressPolicy to `none` (ref: https://github.com/aws/amazon-vpc-cni-k8s/issues/2103 & https://github.com/kubernetes/kops/issues/16255)
+	klog.V(2).Infof("Checking if we need to disable MACAddressPolicy on Ubuntu 22.04")
+	if b.NodeupConfig.Networking.AmazonVPC != nil && b.Distribution == distributions.DistributionUbuntu2204 {
+		klog.V(2).Infof("Detected OS %v; disabling MACAddressPolicy", b.Distribution)
+		// Read the contents of the file /usr/lib/systemd/network/99-default.link into a string
+		origFileName := "/usr/lib/systemd/network/99-default.link"
+		outputFileName := "/etc/systemd/network/99-default.link"
+		input, err := os.ReadFile("/usr/lib/systemd/network/99-default.link")
+		if err != nil {
+			klog.Errorf("Failed to read file %s: %v", origFileName, err)
+			return err
+		}
+
+		// Copy all the relevant entries and replace the one that contains MACAddressPolicy= with MACAddressPolicy=none
+		lines := strings.Split(string(input), "\n")
+		finalOutput := make([]string, 0, len(lines))
+		for i, line := range lines {
+			// We don't want to copy comments or empty lines
+			if strings.HasPrefix(line, "#") || len(line) == 0 {
+				continue
+			} else if strings.Contains(line, "MACAddressPolicy=") {
+				lines[i] = "MACAddressPolicy=none"
+			}
+			finalOutput = append(finalOutput, lines[i])
+		}
+		klog.V(2).Infof("Adding Task to write file %s", outputFileName)
+		c.AddTask(&nodetasks.File{
+			Path:            outputFileName,
+			Contents:        fi.NewStringResource(strings.Join(finalOutput, "\n")),
+			Type:            nodetasks.FileType_File,
+			OnChangeExecute: [][]string{{"systemctl", "restart", "systemd-networkd"}},
+		})
+	}
 	return nil
 }