add kexec previous

Signed-off-by: Sven Dowideit <SvenDowideit@home.org.au>

cmd/control/install.go

@@ -538,16 +538,15 @@ func layDownOS(image, installType, cloudConfig, device, partition, statedir, kap
 		install.PvGrubConfig(menu)
 	}
 	log.Debugf("installRancher")
-	currentCfg, err := installRancher(baseName, VERSION, DIST, kernelArgs+" "+kappend)
+	_, err := installRancher(baseName, VERSION, DIST, kernelArgs+" "+kappend)
 	if err != nil {
 		log.Errorf("%s", err)
 		return err
 	}
 	log.Debugf("installRancher done")
 
-	// Used by upgrade
 	if kexec {
-		power.Kexec(currentCfg, kernelArgs+" "+kappend)
+		power.Kexec(false, filepath.Join(baseName, install.BootDir), kernelArgs+" "+kappend)
 	}
 
 	return nil

cmd/power/power.go

@@ -13,6 +13,7 @@ import (
 	"github.com/docker/engine-api/types"
 	"github.com/docker/engine-api/types/container"
 	"github.com/docker/engine-api/types/filters"
+	"github.com/rancher/os/cmd/control/install"
 	"github.com/rancher/os/log"
 
 	"github.com/rancher/os/docker"
@@ -108,10 +109,31 @@ func reboot(name string, force bool, code uint) {
 		log.Fatalf("%s: Need to be root", os.Args[0])
 	}
 
+	// reboot -f should work even when system-docker is having problems
 	if !force {
+		if kexecFlag || previouskexecFlag || kexecAppendFlag != "" {
+			// pass through the cmdline args
+			name = ""
+		}
 		if err := runDocker(name); err != nil {
 			log.Fatal(err)
 		}
+	}
+
+	if kexecFlag || previouskexecFlag || kexecAppendFlag != "" {
+		// need to mount boot dir, or `system-docker run -v /:/host -w /host/boot` ?
+		baseName := "/mnt/new_img"
+		_, _, err := install.MountDevice(baseName, "", "", false)
+		if err != nil {
+			log.Errorf("ERROR: can't Kexec: %s", err)
+			return
+		}
+		defer util.Unmount(baseName)
+		Kexec(previouskexecFlag, filepath.Join(baseName, install.BootDir), kexecAppendFlag)
+		return
+	}
+
+	if !force {
 		err := shutDownContainers()
 		if err != nil {
 			log.Error(err)

cmd/power/shutdown.go

@@ -11,7 +11,6 @@ import (
 	"github.com/rancher/os/cmd/control/install"
 	"github.com/rancher/os/config"
 	"github.com/rancher/os/log"
-	"github.com/rancher/os/util"
 )
 
 var (
@@ -20,6 +19,8 @@ var (
 	rebootFlag        bool
 	forceFlag         bool
 	kexecFlag         bool
+	previouskexecFlag bool
+	kexecAppendFlag   string
 )
 
 func Shutdown() {
@@ -114,9 +115,19 @@ func Shutdown() {
 		// OR? maybe implement it as a `kexec` cli tool?
 		app.Flags = append(app.Flags, cli.BoolFlag{
 			Name:        "kexec",
-			Usage:       "kexec the default kernel",
+			Usage:       "kexec the default RancherOS cfg",
 			Destination: &kexecFlag,
 		})
+		app.Flags = append(app.Flags, cli.BoolFlag{
+			Name:        "kexec-previous",
+			Usage:       "kexec the previous RancherOS cfg",
+			Destination: &previouskexecFlag,
+		})
+		app.Flags = append(app.Flags, cli.StringFlag{
+			Name:        "kexec-append",
+			Usage:       "kexec using the specified kernel boot params (ignores global.cfg)",
+			Destination: &kexecAppendFlag,
+		})
 	} else {
 		app.Flags = append(app.Flags, cli.BoolFlag{
 			Name:        "r, reboot",
@@ -128,8 +139,12 @@ func Shutdown() {
 	app.Run(os.Args)
 }
 
-func Kexec(bootDir, append string) error {
+func Kexec(previous bool, bootDir, append string) error {
-	cfgFile := filepath.Join(bootDir, "linux-current.cfg")
+	cfg := "linux-current.cfg"
+	if previous {
+		cfg = "linux-previous.cfg"
+	}
+	cfgFile := filepath.Join(bootDir, cfg)
 	vmlinuzFile, initrdFile, err := install.ReadSyslinuxCfg(cfgFile)
 	if err != nil {
 		log.Errorf("%s", err)
@@ -149,7 +164,7 @@ func Kexec(bootDir, append string) error {
 		"kexec",
 		"-l", vmlinuzFile,
 		"--initrd", initrdFile,
-		"--append", "'"+append+"'",
+		"--append", append,
 		"-f")
 	log.Debugf("Run(%#v)", cmd)
 	cmd.Stderr = os.Stderr
@@ -168,21 +183,6 @@ func Reboot() {
 }
 
 func shutdown(c *cli.Context) error {
-	if kexecFlag {
-		if os.Geteuid() != 0 {
-			log.Fatalf("%s: Need to be root", os.Args[0])
-		}
-
-		// need to mount boot dir, or `system-docker run -v /:/host -w /host/boot` ?
-		baseName := "/mnt/new_img"
-		_, _, err := install.MountDevice(baseName, "", "", false)
-		if err != nil {
-			log.Errorf("ERROR: can't Kexec: %s", err)
-			return nil
-		}
-		defer util.Unmount(baseName)
-		return Kexec(filepath.Join(baseName, install.BootDir), "")
-	}
 	// the shutdown command's default is poweroff
 	var powerCmd uint
 	powerCmd = syscall.LINUX_REBOOT_CMD_POWER_OFF

config/disk.go

@@ -64,6 +64,7 @@ func LoadConfigWithPrefix(dirPrefix string) *CloudConfig {
 	cfg := &CloudConfig{}
 	if err := util.Convert(rawCfg, cfg); err != nil {
 		log.Errorf("Failed to parse configuration: %s", err)
+		log.Debugf("Bad cfg:\n%v\n", rawCfg)
 		return &CloudConfig{}
 	}
 	cfg = amendNils(cfg)