Auto resize root disk on AWS (#2191)

cmd/cloudinitexecute/cloudinitexecute.go

@@ -184,7 +184,11 @@ func resizeDevice(cfg *rancherConfig.CloudConfig) error {
 		return err
 	}
 
-	cmd = exec.Command("resize2fs", fmt.Sprintf("%s1", cfg.Rancher.ResizeDevice))
+	targetPartition := fmt.Sprintf("%s1", cfg.Rancher.ResizeDevice)
+	if strings.Contains(cfg.Rancher.ResizeDevice, "nvme") {
+		targetPartition = fmt.Sprintf("%sp1", cfg.Rancher.ResizeDevice)
+	}
+	cmd = exec.Command("resize2fs", targetPartition)
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
 	err = cmd.Run()

config/cloudinit/datasource/datasource.go

@@ -38,6 +38,7 @@ type Metadata struct {
 	Hostname      string
 	SSHPublicKeys map[string]string
 	NetworkConfig netconf.NetworkConfig
+	RootDisk      string
 
 	PublicIPv4  net.IP
 	PublicIPv6  net.IP

config/cloudinit/datasource/metadata/ec2/metadata.go

@@ -32,6 +32,9 @@ const (
 	apiVersion     = "latest/"
 	userdataPath   = apiVersion + "user-data"
 	metadataPath   = apiVersion + "meta-data/"
+
+	defaultXVRootDisk   = "/dev/xvda"
+	defaultNVMeRootDisk = "/dev/nvme0n1"
 )
 
 type MetadataService struct {
@@ -137,6 +140,17 @@ func (ms MetadataService) FetchMetadata() (datasource.Metadata, error) {
 		}
 	}
 
+	// With C5 and M5 instances, EBS volumes are exposed as NVMe block devices.
+	// http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/nvme-ebs-volumes.html
+	metadata.RootDisk = defaultXVRootDisk
+	if instanceType, err := ms.FetchAttribute("instance-type"); err == nil {
+		if strings.HasPrefix(instanceType, "m5") || strings.HasPrefix(instanceType, "c5") {
+			metadata.RootDisk = defaultNVMeRootDisk
+		}
+	} else if _, ok := err.(pkg.ErrNotFound); !ok {
+		return metadata, err
+	}
+
 	return metadata, nil
 }
 

config/cloudinit/datasource/metadata/ec2/metadata_test.go

@@ -67,6 +67,7 @@ func TestFetchMetadata(t *testing.T) {
 				PrivateIPv4:   net.ParseIP("1.2.3.4"),
 				PublicIPv4:    net.ParseIP("5.6.7.8"),
 				SSHPublicKeys: map[string]string{"test1": "key"},
+				RootDisk:      "/dev/xvda",
 				NetworkConfig: netconf.NetworkConfig{
 					Interfaces: map[string]netconf.InterfaceConfig{
 					/*			"eth0": netconf.InterfaceConfig{
@@ -89,12 +90,14 @@ func TestFetchMetadata(t *testing.T) {
 				"/2009-04-04/meta-data/public-keys":               "0=test1\n",
 				"/2009-04-04/meta-data/public-keys/0":             "openssh-key",
 				"/2009-04-04/meta-data/public-keys/0/openssh-key": "key",
+				"/2009-04-04/meta-data/instance-type":             "m5.large",
 			},
 			expect: datasource.Metadata{
 				Hostname:      "host",
 				PrivateIPv4:   net.ParseIP("21.2.3.4"),
 				PublicIPv4:    net.ParseIP("25.6.7.8"),
 				SSHPublicKeys: map[string]string{"test1": "key"},
+				RootDisk:      "/dev/nvme0n1",
 				NetworkConfig: netconf.NetworkConfig{
 					Interfaces: map[string]netconf.InterfaceConfig{
 					/*						"eth0": netconf.InterfaceConfig{

config/disk.go

@@ -205,6 +205,11 @@ func mergeMetadata(rawCfg map[interface{}]interface{}, md datasource.Metadata) m
 
 	out["ssh_authorized_keys"] = finalKeys
 
+	rancherOut, _ := out["rancher"].(map[interface{}]interface{})
+	if _, ok := rancherOut["resize_device"]; md.RootDisk != "" && !ok {
+		rancherOut["resize_device"] = md.RootDisk
+	}
+
 	return out
 }