Merge pull request #889 from jcrussell/issue-854

minimega/vmconfiger: several bug fixes, fix #854

src/minimega/container.go

@@ -259,6 +259,22 @@ type ContainerConfig struct {
 	//
 	// Note: this configuration only applies to containers.
 	Fifos uint64
+
+	// Attach one or more volumes to a container. These directories will be
+	// mounted inside the container at the specified location.
+	//
+	// For example, to mount /scratch/data to /data inside the container:
+	//
+	//  vm config volume /data /scratch/data
+	//
+	// Commands with the same <key> will overwrite previous volumes:
+	//
+	//  vm config volume /data /scratch/data2
+	//  vm config volume /data
+	//  /scratch/data2
+	//
+	// Note: this configuration only applies to containers.
+	VolumePaths map[string]string
 }
 
 type ContainerVM struct {
@@ -372,8 +388,8 @@ func containerTeardown() {
 //	7 :  uuid
 //	8 :  number of fifos
 //	9 :  preinit program
-//	10 :  init program (relative to filesystem path)
-//	11:  init args
+//	10+: source:target volumes, `--` signifies end
+//	11+ :  init program and args (relative to filesystem path)
 func containerShim() {
 	args := flag.Args()
 	if flag.NArg() < 11 { // 11 because init args can be nil
@@ -411,7 +427,19 @@ func containerShim() {
 		log.Fatalln(err)
 	}
 	vmPreinit := args[9]
-	vmInit := args[10:]
+
+	// find `--` separator between vmVolumes and vmInit
+	var vmVolumes, vmInit []string
+	for i, v := range args[10:] {
+		if v == "--" {
+			vmInit = args[10+i+1:]
+			break
+		}
+		vmVolumes = append(vmVolumes, v)
+	}
+
+	log.Debug("vmVolumes: %v", vmVolumes)
+	log.Debug("vmInit: %v", vmInit)
 
 	// set hostname
 	log.Debug("vm %v hostname", vmID)
@@ -435,6 +463,13 @@ func containerShim() {
 		log.Fatal("containerMountDefaults: %v", err)
 	}
 
+	// mount volumes
+	log.Debug("vm %v containerMountVolumes", vmID)
+	err = containerMountVolumes(vmFSPath, vmVolumes)
+	if err != nil {
+		log.Fatal("containerMountVolumes: %v", err)
+	}
+
 	// mknod
 	log.Debug("vm %v containerMknodDevices", vmID)
 	err = containerMknodDevices(vmFSPath)
@@ -590,8 +625,11 @@ func (old ContainerConfig) Copy() ContainerConfig {
 	// Copy all fields
 	res := old
 
-	// Make deep copy of slices
-	// none yet - placeholder
+	// Make deep copy of volumes
+	res.VolumePaths = map[string]string{}
+	for k, v := range old.VolumePaths {
+		res.VolumePaths[k] = v
+	}
 
 	return res
 }
@@ -717,6 +755,8 @@ func (vm *ContainerVM) Info(field string) (string, error) {
 	switch field {
 	case "console_port":
 		return strconv.Itoa(vm.ConsolePort), nil
+	case "volume":
+		return marshal(vm.VolumePaths), nil
 	}
 
 	return vm.ContainerConfig.Info(field)
@@ -762,6 +802,10 @@ func (vm *ContainerConfig) String() string {
 	fmt.Fprintf(w, "Init:\t%v\n", vm.Init)
 	fmt.Fprintf(w, "Pre-init:\t%v\n", vm.Preinit)
 	fmt.Fprintf(w, "FIFOs:\t%v\n", vm.Fifos)
+	fmt.Fprintf(w, "Volumes:\t\n")
+	for k, v := range vm.VolumePaths {
+		fmt.Fprintf(w, "\t%v -> %v\n", k, v)
+	}
 	w.Flush()
 	fmt.Fprintln(&o)
 	return o.String()
@@ -881,6 +925,13 @@ func (vm *ContainerVM) launch() error {
 		fmt.Sprintf("%v", vm.Fifos),
 		preinit,
 	}
+	for k, v := range vm.VolumePaths {
+		// Create source:target pairs
+		// TODO: should probably handle spaces
+		args = append(args, fmt.Sprintf("%v:%v", v, k))
+	}
+	// denotes end of volumes
+	args = append(args, "--")
 	args = append(args, vm.Init...)
 
 	// launch the container
@@ -1549,6 +1600,28 @@ func containerMountDefaults(fsPath string) error {
 	return nil
 }
 
+func containerMountVolumes(fsPath string, volumes []string) error {
+	for _, v := range volumes {
+		f := strings.Split(v, ":")
+		if len(f) != 2 {
+			return fmt.Errorf("invalid volume, expected `source:target`: %v", v)
+		}
+
+		source := f[0]
+		target := filepath.Join(fsPath, f[1])
+
+		if err := os.MkdirAll(target, 0755); err != nil {
+			return err
+		}
+
+		if err := syscall.Mount(source, target, "", syscall.MS_BIND, ""); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 // aggressively cleanup container cruff, called by the nuke api
 func containerNuke() {
 	// walk minimega cgroups for tasks, killing each one
@@ -1653,6 +1726,7 @@ func containerCleanCgroupDirs() {
 		filepath.Join(*f_cgroup, "freezer", "minimega"),
 		filepath.Join(*f_cgroup, "memory", "minimega"),
 		filepath.Join(*f_cgroup, "devices", "minimega"),
+		filepath.Join(*f_cgroup, "cpu", "minimega"),
 	}
 	for _, d := range paths {
 		_, err := os.Stat(d)

src/minimega/misc.go

@@ -6,6 +6,7 @@ package main
 
 import (
 	"bytes"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"image"
@@ -294,6 +295,18 @@ func mustWrite(fpath, data string) {
 	}
 }
 
+// marshal returns the JSON-marshaled version of `v`. If we are unable to
+// marshal it for whatever reason, we log an error and return an empty string.
+func marshal(v interface{}) string {
+	b, err := json.Marshal(v)
+	if err != nil {
+		log.Error("unable to marshal %v: %v", v, err)
+		return ""
+	}
+
+	return string(b)
+}
+
 // PermStrings creates a random permutation of the source slice using the
 // "inside-out" version of the Fisher-Yates algorithm.
 func PermStrings(source []string) []string {

src/minimega/vm.go

@@ -134,7 +134,8 @@ var vmInfo = []string{
 	"vcpus", "disk", "snapshot", "initrd", "kernel", "cdrom", "migrate",
 	"append", "serial-ports", "virtio-ports", "vnc_port",
 	// container fields
-	"filesystem", "hostname", "init", "preinit", "fifo", "console_port",
+	"filesystem", "hostname", "init", "preinit", "fifo", "volume",
+	"console_port",
 	// more generic fields (tags can be huge so throw it at the end)
 	"tags",
 }
@@ -630,7 +631,7 @@ func (vm *BaseVM) Info(field string) (string, error) {
 			}
 		}
 	case "tags":
-		return vm.Tags.String(), nil
+		return marshal(vm.Tags), nil
 	case "cc_active":
 		return strconv.FormatBool(vm.ActiveCC), nil
 	default:

src/minimega/vmconfig.go

@@ -9,15 +9,11 @@ package main
 import (
 	"bridge"
 	"bytes"
-	"encoding/json"
 	"fmt"
-	log "minilog"
 	"strings"
 	"text/tabwriter"
 )
 
-type Tags map[string]string
-
 // VMConfig contains all the configs possible for a VM. When a VM of a
 // particular kind is launched, only the pertinent configuration is copied so
 // fields from other configs will have the zero value for the field type.
@@ -66,8 +62,9 @@ type BaseConfig struct {
 	// Networks for the VM, handler is not generated by vmconfiger.
 	Networks []NetConfig
 
-	// Tags for the VM, handler is not generated by vmconfiger.
-	Tags Tags
+	// Set tags in the same manner as "vm tag". These tags will apply to all
+	// newly launched VMs.
+	Tags map[string]string
 }
 
 // NetConfig contains all the network-related config for an interface. The IP
@@ -141,7 +138,7 @@ func (vm *BaseConfig) String() string {
 	fmt.Fprintf(w, "Schedule host:\t%v\n", vm.Schedule)
 	fmt.Fprintf(w, "Coschedule limit:\t%v\n", vm.Coschedule)
 	if vm.Tags != nil {
-		fmt.Fprintf(w, "Tags:\t%v\n", vm.Tags)
+		fmt.Fprintf(w, "Tags:\t%v\n", marshal(vm.Tags))
 	} else {
 		fmt.Fprint(w, "Tags:\t{}\n")
 	}
@@ -186,16 +183,6 @@ func (vm *BaseConfig) QosString(b, t, i string) string {
 	return strings.Trim(val, " ")
 }
 
-func (t Tags) String() string {
-	res, err := json.Marshal(t)
-	if err != nil {
-		log.Error("unable to marshal Tags: %v", err)
-		return ""
-	}
-
-	return string(res)
-}
-
 // TODO: Handle if there are spaces or commas in the tap/bridge names
 func (net NetConfig) String() (s string) {
 	parts := []string{}

src/minimega/vmconfig_cli.go

@@ -108,17 +108,6 @@ Calling vm config net with no arguments prints the current configuration.`,
 		},
 		Call: wrapSimpleCLI(cliVMConfigNet),
 	},
-	{ // vm config tag
-		HelpShort: "set tags for newly launched VMs",
-		HelpLong: `
-Set tags in the same manner as "vm tag". These tags will apply to all newly
-launched VMs.`,
-		Patterns: []string{
-			"vm config tag [key]",
-			"vm config tag <key> <value>",
-		},
-		Call: wrapSimpleCLI(cliVMConfigTag),
-	},
 	{ // vm config qemu-override
 		HelpShort: "override parts of the QEMU launch string",
 		HelpLong: `
@@ -216,28 +205,6 @@ func cliVMConfigNet(c *minicli.Command, resp *minicli.Response) error {
 	return nil
 }
 
-func cliVMConfigTag(c *minicli.Command, resp *minicli.Response) error {
-	k := c.StringArgs["key"]
-
-	// if Tags were cleared, reinitialize them
-	if vmConfig.Tags == nil {
-		vmConfig.Tags = map[string]string{}
-	}
-
-	if v, ok := c.StringArgs["value"]; ok {
-		// Setting a new value
-		vmConfig.Tags[k] = v
-	} else if k != "" {
-		// Printing a single tag
-		resp.Response = vmConfig.Tags[k]
-	} else {
-		// Printing all configured tags
-		resp.Response = vmConfig.Tags.String()
-	}
-
-	return nil
-}
-
 func cliVMConfigQemuOverride(c *minicli.Command, resp *minicli.Response) error {
 	if len(c.StringArgs) == 0 {
 		resp.Response = vmConfig.qemuOverrideString()