Fix DHCP hostname being overwritten

cmd/cloudinit/cloudinit.go

@@ -22,7 +22,6 @@ import (
 	"os"
 	"strings"
 	"sync"
-	"syscall"
 	"time"
 
 	yaml "github.com/cloudfoundry-incubator/candiedyaml"
@@ -169,32 +168,12 @@ func fetchUserData() ([]byte, datasource.Metadata, error) {
 	return userDataBytes, metadata, nil
 }
 
-func SetHostname(cc *rancherConfig.CloudConfig) (string, error) {
-	name, _ := os.Hostname()
-	if cc.Hostname != "" {
-		name = cc.Hostname
-	}
-	if name != "" {
-		//set hostname
-		if err := syscall.Sethostname([]byte(name)); err != nil {
-			log.WithFields(log.Fields{"err": err, "hostname": name}).Error("Error setting hostname")
-			return "", err
-		}
-	}
-
-	return name, nil
-}
-
 func executeCloudConfig() error {
 	cc, err := rancherConfig.LoadConfig()
 	if err != nil {
 		return err
 	}
 
-	if _, err := SetHostname(cc); err != nil {
-		return err
-	}
-
 	if len(cc.SSHAuthorizedKeys) > 0 {
 		authorizeSSHKeys("rancher", cc.SSHAuthorizedKeys, sshKeyName)
 		authorizeSSHKeys("docker", cc.SSHAuthorizedKeys, sshKeyName)

cmd/network/network.go

@@ -1,19 +1,16 @@
 package network
 
 import (
-	"bufio"
 	"flag"
-	"io/ioutil"
 	"os"
 	"os/exec"
-	"strings"
 
 	log "github.com/Sirupsen/logrus"
 
 	"github.com/docker/libnetwork/resolvconf"
 	"github.com/rancher/netconf"
-	"github.com/rancher/os/cmd/cloudinit"
 	"github.com/rancher/os/config"
+	"github.com/rancher/os/hostname"
 )
 
 const (
@@ -49,39 +46,25 @@ func Main() {
 		log.Fatal(err)
 	}
 
-	hostname, _ := cloudinit.SetHostname(cfg) // ignore error
-	log.Infof("Network: hostname: '%s'", hostname)
-
 	if _, err := resolvconf.Build("/etc/resolv.conf", cfg.Rancher.Network.Dns.Nameservers, cfg.Rancher.Network.Dns.Search, nil); err != nil {
 		log.Error(err)
 	}
 
+	if err := hostname.SetHostnameFromCloudConfig(cfg); err != nil {
+		log.Error(err)
+	}
+
 	if err := netconf.ApplyNetworkConfigs(&cfg.Rancher.Network); err != nil {
 		log.Error(err)
 	}
 
-	hostname, _ = cloudinit.SetHostname(cfg) // ignore error
-	log.Infof("Network: hostname: '%s' (from DHCP, if not set by cloud-config)", hostname)
-	if hostname != "" {
-		hosts, err := os.Open("/etc/hosts")
-		defer hosts.Close()
-		if err != nil {
-			log.Fatal(err)
-		}
-		lines := bufio.NewScanner(hosts)
-		hostsContent := ""
-		for lines.Scan() {
-			line := strings.TrimSpace(lines.Text())
-			fields := strings.Fields(line)
-			if len(fields) > 0 && fields[0] == "127.0.1.1" {
-				hostsContent += "127.0.1.1 " + hostname + "\n"
-				continue
-			}
-			hostsContent += line + "\n"
-		}
-		if err := ioutil.WriteFile("/etc/hosts", []byte(hostsContent), 0600); err != nil {
+	dhcpHostname := cfg.Hostname == ""
+	if err := netconf.RunDhcp(&cfg.Rancher.Network, dhcpHostname); err != nil {
 		log.Error(err)
 	}
+
+	if err := hostname.SyncHostname(); err != nil {
+		log.Error(err)
 	}
 
 	if f, err := os.Create(NETWORK_DONE); err != nil {

config/types.go

@@ -71,6 +71,7 @@ type CloudConfig struct {
 	SSHAuthorizedKeys []string      `yaml:"ssh_authorized_keys"`
 	WriteFiles        []config.File `yaml:"write_files"`
 	Hostname          string        `yaml:"hostname"`
+	DefaultHostname   string        `yaml:"default_hostname"`
 
 	Rancher RancherConfig `yaml:"rancher,omitempty"`
 }

hostname/hostname.go

@@ -0,0 +1,62 @@
+package hostname
+
+import (
+	"bufio"
+	"github.com/rancher/os/config"
+	"io/ioutil"
+	"os"
+	"strings"
+	"syscall"
+)
+
+func SetHostnameFromCloudConfig(cc *config.CloudConfig) error {
+	var hostname string
+	if cc.Hostname == "" {
+		hostname = cc.DefaultHostname
+	} else {
+		hostname = cc.Hostname
+	}
+
+	if hostname == "" {
+		return nil
+	}
+
+	// set hostname
+	if err := syscall.Sethostname([]byte(hostname)); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func SyncHostname() error {
+	hostname, err := os.Hostname()
+	if err != nil {
+		return err
+	}
+	if hostname == "" {
+		return nil
+	}
+
+	hosts, err := os.Open("/etc/hosts")
+	defer hosts.Close()
+	if err != nil {
+		return err
+	}
+	lines := bufio.NewScanner(hosts)
+	hostsContent := ""
+	for lines.Scan() {
+		line := strings.TrimSpace(lines.Text())
+		fields := strings.Fields(line)
+		if len(fields) > 0 && fields[0] == "127.0.1.1" {
+			hostsContent += "127.0.1.1 " + hostname + "\n"
+			continue
+		}
+		hostsContent += line + "\n"
+	}
+	if err := ioutil.WriteFile("/etc/hosts", []byte(hostsContent), 0600); err != nil {
+		return err
+	}
+
+	return nil
+}

os-config.tpl.yml

@@ -1,4 +1,4 @@
-hostname: {{.HOSTNAME_DEFAULT}}
+default_hostname: {{.HOSTNAME_DEFAULT}}
 rancher:
   bootstrap:
     state-script:

tests/integration/assets/test_12/cloud-config.yml

@@ -0,0 +1,3 @@
+#cloud-config
+ssh_authorized_keys:
+  - ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDUlsWAL5Rf0Wis/A7k7Tlqx0fZS60VzCZrPZYbP/wkL95jv0XzCx8bd1rZHeybblHPDNpND3BLv4qPY5DxRyexF4seGuzcJI/pOvGUGjQondeMPgDTFEo5w939gSdeTZcfXzQ0wAVhzwDbgH4zPfMzbdoo8Aiu9jkKljXw8IFju0gh+t6iKkGZCIjKT9o7zza1vGfkodhvi2V3VzPdNO28gaxZaRNtmBYUoVnGyR6nXN1Q3CJaVuh5o6GPCOqrhHNbYOFZKBpDiHbxPhVpxHQD2+8yUSGTG7WW75FfZePja5y8d0c/O5L37ZYx4AZAd3KgQYDBT2XCEJGQNawNbfpt

tests/integration/assets/test_13/cloud-config.yml

@@ -0,0 +1,4 @@
+#cloud-config
+hostname: rancher-test
+ssh_authorized_keys:
+  - ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDUlsWAL5Rf0Wis/A7k7Tlqx0fZS60VzCZrPZYbP/wkL95jv0XzCx8bd1rZHeybblHPDNpND3BLv4qPY5DxRyexF4seGuzcJI/pOvGUGjQondeMPgDTFEo5w939gSdeTZcfXzQ0wAVhzwDbgH4zPfMzbdoo8Aiu9jkKljXw8IFju0gh+t6iKkGZCIjKT9o7zza1vGfkodhvi2V3VzPdNO28gaxZaRNtmBYUoVnGyR6nXN1Q3CJaVuh5o6GPCOqrhHNbYOFZKBpDiHbxPhVpxHQD2+8yUSGTG7WW75FfZePja5y8d0c/O5L37ZYx4AZAd3KgQYDBT2XCEJGQNawNbfpt

tests/integration/rostest/test_12_dhcp_hostname.py

@@ -0,0 +1,21 @@
+import pytest
+import rostest.util as u
+from rostest.util import SSH
+
+ssh_command = ['./scripts/ssh', '--qemu', '--key', './tests/integration/assets/test.key']
+cloud_config_path = './tests/integration/assets/test_12/cloud-config.yml'
+
+
+@pytest.fixture(scope="module")
+def qemu(request):
+    q = u.run_qemu(request, ['--cloud-config', cloud_config_path])
+    u.flush_out(q.stdout)
+    return q
+
+
+@pytest.mark.timeout(40)
+def test_dhcp_hostname(qemu):
+    SSH(qemu, ssh_command).check_call('''
+hostname | grep rancher-dev
+cat /etc/hosts | grep rancher-dev
+    ''')

tests/integration/rostest/test_13_cloud_config_hostname.py

@@ -0,0 +1,21 @@
+import pytest
+import rostest.util as u
+from rostest.util import SSH
+
+ssh_command = ['./scripts/ssh', '--qemu', '--key', './tests/integration/assets/test.key']
+cloud_config_path = './tests/integration/assets/test_13/cloud-config.yml'
+
+
+@pytest.fixture(scope="module")
+def qemu(request):
+    q = u.run_qemu(request, ['--cloud-config', cloud_config_path])
+    u.flush_out(q.stdout)
+    return q
+
+
+@pytest.mark.timeout(40)
+def test_cloud_config_hostname(qemu):
+    SSH(qemu, ssh_command).check_call('''
+hostname | grep rancher-test
+cat /etc/hosts | grep rancher-test
+    ''')

trash.yml

@@ -70,7 +70,7 @@ import:
   version: v1.10.3
 
 - package: github.com/rancher/netconf
-  version: 6cd9ea0b3a45482c9e9aee9be9ca88c96b2f71e6
+  version: 6a771a0593c146f35634c405ab9ccfec50db65e1
 
 - package: github.com/ryanuber/go-glob
   version: 0067a9abd927e50aed5190662702f81231413ae0

vendor/github.com/rancher/netconf/netconf_linux.go

@@ -23,7 +23,7 @@ const (
 )
 
 var (
-	defaultDhcpArgs = []string{"dhcpcd", "-MA4", "-e", "force_hostname=true"}
+	defaultDhcpArgs = []string{"dhcpcd", "-MA4"}
 )
 
 func createInterfaces(netCfg *NetworkConfig) {
@@ -168,36 +168,48 @@ func ApplyNetworkConfigs(netCfg *NetworkConfig) error {
 		return err
 	}
 
-	dhcpLinks := map[string]string{}
-
 	//apply network config
 	for _, link := range links {
 		linkName := link.Attrs().Name
-		if match, ok := findMatch(link, netCfg); ok {
-			if match.DHCP {
-				dhcpLinks[link.Attrs().Name] = match.DHCPArgs
-			} else if err = applyInterfaceConfig(link, match); err != nil {
+		if match, ok := findMatch(link, netCfg); ok && !match.DHCP {
+			if err := applyInterfaceConfig(link, match); err != nil {
 				log.Errorf("Failed to apply settings to %s : %v", linkName, err)
 			}
 		}
 	}
 
+	runCmds(netCfg.PostCmds, "")
+	return err
+}
+
+func RunDhcp(netCfg *NetworkConfig, dhcpHostname bool) error {
+	links, err := netlink.LinkList()
+	if err != nil {
+		return err
+	}
+
+	dhcpLinks := map[string]string{}
+	for _, link := range links {
+		if match, ok := findMatch(link, netCfg); ok && match.DHCP {
+			dhcpLinks[link.Attrs().Name] = match.DHCPArgs
+		}
+	}
+
 	//run dhcp
 	wg := sync.WaitGroup{}
 	for iface, args := range dhcpLinks {
 		wg.Add(1)
 		go func(iface, args string) {
-			runDhcp(netCfg, iface, args)
+			runDhcp(netCfg, iface, args, dhcpHostname)
 			wg.Done()
 		}(iface, args)
 	}
 	wg.Wait()
 
-	runCmds(netCfg.PostCmds, "")
 	return err
 }
 
-func runDhcp(netCfg *NetworkConfig, iface string, argstr string) {
+func runDhcp(netCfg *NetworkConfig, iface string, argstr string, dhcpHostname bool) {
 	log.Infof("Running DHCP on %s", iface)
 	args := []string{}
 	if argstr != "" {
@@ -215,6 +227,10 @@ func runDhcp(netCfg *NetworkConfig, iface string, argstr string) {
 		args = append(args, "--nohook", "resolv.conf")
 	}
 
+	if dhcpHostname {
+		args = append(args, "-e", "force_hostname=true")
+	}
+
 	args = append(args, iface)
 	cmd := exec.Command(args[0], args[1:]...)
 	cmd.Stdout = os.Stdout