open-nomad/client/driver/lxc.go
2017-09-26 15:26:33 -07:00

523 lines
14 KiB
Go

//+build linux,lxc
package driver
import (
"context"
"encoding/json"
"fmt"
"log"
"os"
"path/filepath"
"strconv"
"strings"
"syscall"
"time"
"github.com/hashicorp/nomad/client/config"
"github.com/hashicorp/nomad/client/fingerprint"
"github.com/hashicorp/nomad/client/stats"
"github.com/hashicorp/nomad/helper/fields"
"github.com/hashicorp/nomad/nomad/structs"
"github.com/mitchellh/mapstructure"
dstructs "github.com/hashicorp/nomad/client/driver/structs"
cstructs "github.com/hashicorp/nomad/client/structs"
lxc "gopkg.in/lxc/go-lxc.v2"
)
const (
// lxcConfigOption is the key for enabling the LXC driver in the
// Config.Options map.
lxcConfigOption = "driver.lxc.enable"
// containerMonitorIntv is the interval at which the driver checks if the
// container is still alive
containerMonitorIntv = 2 * time.Second
)
var (
LXCMeasuredCpuStats = []string{"System Mode", "User Mode", "Percent"}
LXCMeasuredMemStats = []string{"RSS", "Cache", "Swap", "Max Usage", "Kernel Usage", "Kernel Max Usage"}
)
// Add the lxc driver to the list of builtin drivers
func init() {
BuiltinDrivers["lxc"] = NewLxcDriver
}
// LxcDriver allows users to run LXC Containers
type LxcDriver struct {
DriverContext
fingerprint.StaticFingerprinter
}
// LxcDriverConfig is the configuration of the LXC Container
type LxcDriverConfig struct {
Template string
Distro string
Release string
Arch string
ImageVariant string `mapstructure:"image_variant"`
ImageServer string `mapstructure:"image_server"`
GPGKeyID string `mapstructure:"gpg_key_id"`
GPGKeyServer string `mapstructure:"gpg_key_server"`
DisableGPGValidation bool `mapstructure:"disable_gpg"`
FlushCache bool `mapstructure:"flush_cache"`
ForceCache bool `mapstructure:"force_cache"`
TemplateArgs []string `mapstructure:"template_args"`
LogLevel string `mapstructure:"log_level"`
Verbosity string
}
// NewLxcDriver returns a new instance of the LXC driver
func NewLxcDriver(ctx *DriverContext) Driver {
return &LxcDriver{DriverContext: *ctx}
}
// Validate validates the lxc driver configuration
func (d *LxcDriver) Validate(config map[string]interface{}) error {
fd := &fields.FieldData{
Raw: config,
Schema: map[string]*fields.FieldSchema{
"template": {
Type: fields.TypeString,
Required: true,
},
"distro": {
Type: fields.TypeString,
Required: false,
},
"release": {
Type: fields.TypeString,
Required: false,
},
"arch": {
Type: fields.TypeString,
Required: false,
},
"image_variant": {
Type: fields.TypeString,
Required: false,
},
"image_server": {
Type: fields.TypeString,
Required: false,
},
"gpg_key_id": {
Type: fields.TypeString,
Required: false,
},
"gpg_key_server": {
Type: fields.TypeString,
Required: false,
},
"disable_gpg": {
Type: fields.TypeString,
Required: false,
},
"flush_cache": {
Type: fields.TypeString,
Required: false,
},
"force_cache": {
Type: fields.TypeString,
Required: false,
},
"template_args": {
Type: fields.TypeArray,
Required: false,
},
"log_level": {
Type: fields.TypeString,
Required: false,
},
"verbosity": {
Type: fields.TypeString,
Required: false,
},
},
}
if err := fd.Validate(); err != nil {
return err
}
return nil
}
func (d *LxcDriver) Abilities() DriverAbilities {
return DriverAbilities{
SendSignals: false,
Exec: false,
}
}
func (d *LxcDriver) FSIsolation() cstructs.FSIsolation {
return cstructs.FSIsolationImage
}
// Fingerprint fingerprints the lxc driver configuration
func (d *LxcDriver) Fingerprint(cfg *config.Config, node *structs.Node) (bool, error) {
enabled := cfg.ReadBoolDefault(lxcConfigOption, true)
if !enabled && !cfg.DevMode {
return false, nil
}
version := lxc.Version()
if version == "" {
return false, nil
}
node.Attributes["driver.lxc.version"] = version
node.Attributes["driver.lxc"] = "1"
return true, nil
}
func (d *LxcDriver) Prestart(*ExecContext, *structs.Task) (*PrestartResponse, error) {
return nil, nil
}
// Start starts the LXC Driver
func (d *LxcDriver) Start(ctx *ExecContext, task *structs.Task) (*StartResponse, error) {
var driverConfig LxcDriverConfig
if err := mapstructure.WeakDecode(task.Config, &driverConfig); err != nil {
return nil, err
}
lxcPath := lxc.DefaultConfigPath()
if path := d.config.Read("driver.lxc.path"); path != "" {
lxcPath = path
}
containerName := fmt.Sprintf("%s-%s", task.Name, d.DriverContext.allocID)
c, err := lxc.NewContainer(containerName, lxcPath)
if err != nil {
return nil, fmt.Errorf("unable to initialize container: %v", err)
}
var verbosity lxc.Verbosity
switch driverConfig.Verbosity {
case "verbose":
verbosity = lxc.Verbose
case "", "quiet":
verbosity = lxc.Quiet
default:
return nil, fmt.Errorf("lxc driver config 'verbosity' can only be either quiet or verbose")
}
c.SetVerbosity(verbosity)
var logLevel lxc.LogLevel
switch driverConfig.LogLevel {
case "trace":
logLevel = lxc.TRACE
case "debug":
logLevel = lxc.DEBUG
case "info":
logLevel = lxc.INFO
case "warn":
logLevel = lxc.WARN
case "", "error":
logLevel = lxc.ERROR
default:
return nil, fmt.Errorf("lxc driver config 'log_level' can only be trace, debug, info, warn or error")
}
c.SetLogLevel(logLevel)
logFile := filepath.Join(ctx.TaskDir.LogDir, fmt.Sprintf("%v-lxc.log", task.Name))
c.SetLogFile(logFile)
options := lxc.TemplateOptions{
Template: driverConfig.Template,
Distro: driverConfig.Distro,
Release: driverConfig.Release,
Arch: driverConfig.Arch,
FlushCache: driverConfig.FlushCache,
DisableGPGValidation: driverConfig.DisableGPGValidation,
ExtraArgs: driverConfig.TemplateArgs,
}
if err := c.Create(options); err != nil {
return nil, fmt.Errorf("unable to create container: %v", err)
}
// Set the network type to none
if err := c.SetConfigItem("lxc.network.type", "none"); err != nil {
return nil, fmt.Errorf("error setting network type configuration: %v", err)
}
// Bind mount the shared alloc dir and task local dir in the container
mounts := []string{
fmt.Sprintf("%s local none rw,bind,create=dir", ctx.TaskDir.LocalDir),
fmt.Sprintf("%s alloc none rw,bind,create=dir", ctx.TaskDir.SharedAllocDir),
fmt.Sprintf("%s secrets none rw,bind,create=dir", ctx.TaskDir.SecretsDir),
}
for _, mnt := range mounts {
if err := c.SetConfigItem("lxc.mount.entry", mnt); err != nil {
return nil, fmt.Errorf("error setting bind mount %q error: %v", mnt, err)
}
}
// Start the container
if err := c.Start(); err != nil {
return nil, fmt.Errorf("unable to start container: %v", err)
}
// Set the resource limits
if err := c.SetMemoryLimit(lxc.ByteSize(task.Resources.MemoryMB) * lxc.MB); err != nil {
return nil, fmt.Errorf("unable to set memory limits: %v", err)
}
if err := c.SetCgroupItem("cpu.shares", strconv.Itoa(task.Resources.CPU)); err != nil {
return nil, fmt.Errorf("unable to set cpu shares: %v", err)
}
h := lxcDriverHandle{
container: c,
initPid: c.InitPid(),
lxcPath: lxcPath,
logger: d.logger,
killTimeout: GetKillTimeout(task.KillTimeout, d.DriverContext.config.MaxKillTimeout),
maxKillTimeout: d.DriverContext.config.MaxKillTimeout,
totalCpuStats: stats.NewCpuStats(),
userCpuStats: stats.NewCpuStats(),
systemCpuStats: stats.NewCpuStats(),
waitCh: make(chan *dstructs.WaitResult, 1),
doneCh: make(chan bool, 1),
}
go h.run()
return &StartResponse{Handle: &h}, nil
}
func (d *LxcDriver) Cleanup(*ExecContext, *CreatedResources) error { return nil }
// Open creates the driver to monitor an existing LXC container
func (d *LxcDriver) Open(ctx *ExecContext, handleID string) (DriverHandle, error) {
pid := &lxcPID{}
if err := json.Unmarshal([]byte(handleID), pid); err != nil {
return nil, fmt.Errorf("Failed to parse handle '%s': %v", handleID, err)
}
var container *lxc.Container
containers := lxc.Containers(pid.LxcPath)
for _, c := range containers {
if c.Name() == pid.ContainerName {
container = &c
break
}
}
if container == nil {
return nil, fmt.Errorf("container %v not found", pid.ContainerName)
}
handle := lxcDriverHandle{
container: container,
initPid: container.InitPid(),
lxcPath: pid.LxcPath,
logger: d.logger,
killTimeout: pid.KillTimeout,
maxKillTimeout: d.DriverContext.config.MaxKillTimeout,
totalCpuStats: stats.NewCpuStats(),
userCpuStats: stats.NewCpuStats(),
systemCpuStats: stats.NewCpuStats(),
waitCh: make(chan *dstructs.WaitResult, 1),
doneCh: make(chan bool, 1),
}
go handle.run()
return &handle, nil
}
// lxcDriverHandle allows controlling the lifecycle of an lxc container
type lxcDriverHandle struct {
container *lxc.Container
initPid int
lxcPath string
logger *log.Logger
killTimeout time.Duration
maxKillTimeout time.Duration
totalCpuStats *stats.CpuStats
userCpuStats *stats.CpuStats
systemCpuStats *stats.CpuStats
waitCh chan *dstructs.WaitResult
doneCh chan bool
}
type lxcPID struct {
ContainerName string
InitPid int
LxcPath string
KillTimeout time.Duration
}
func (h *lxcDriverHandle) ID() string {
pid := lxcPID{
ContainerName: h.container.Name(),
InitPid: h.initPid,
LxcPath: h.lxcPath,
KillTimeout: h.killTimeout,
}
data, err := json.Marshal(pid)
if err != nil {
h.logger.Printf("[ERR] driver.lxc: failed to marshal lxc PID to JSON: %v", err)
}
return string(data)
}
func (h *lxcDriverHandle) WaitCh() chan *dstructs.WaitResult {
return h.waitCh
}
func (h *lxcDriverHandle) Update(task *structs.Task) error {
h.killTimeout = GetKillTimeout(task.KillTimeout, h.killTimeout)
return nil
}
func (h *lxcDriverHandle) Exec(ctx context.Context, cmd string, args []string) ([]byte, int, error) {
return nil, 0, fmt.Errorf("lxc driver cannot execute commands")
}
func (h *lxcDriverHandle) Kill() error {
name := h.container.Name()
h.logger.Printf("[INFO] driver.lxc: shutting down container %q", name)
if err := h.container.Shutdown(h.killTimeout); err != nil {
h.logger.Printf("[INFO] driver.lxc: shutting down container %q failed: %v", name, err)
if err := h.container.Stop(); err != nil {
h.logger.Printf("[ERR] driver.lxc: error stopping container %q: %v", name, err)
}
}
close(h.doneCh)
return nil
}
func (h *lxcDriverHandle) Signal(s os.Signal) error {
return fmt.Errorf("LXC does not support signals")
}
func (h *lxcDriverHandle) Stats() (*cstructs.TaskResourceUsage, error) {
cpuStats, err := h.container.CPUStats()
if err != nil {
return nil, nil
}
total, err := h.container.CPUTime()
if err != nil {
return nil, nil
}
t := time.Now()
// Get the cpu stats
system := cpuStats["system"]
user := cpuStats["user"]
cs := &cstructs.CpuStats{
SystemMode: h.systemCpuStats.Percent(float64(system)),
UserMode: h.systemCpuStats.Percent(float64(user)),
Percent: h.totalCpuStats.Percent(float64(total)),
TotalTicks: float64(user + system),
Measured: LXCMeasuredCpuStats,
}
// Get the Memory Stats
memData := map[string]uint64{
"rss": 0,
"cache": 0,
"swap": 0,
}
rawMemStats := h.container.CgroupItem("memory.stat")
for _, rawMemStat := range rawMemStats {
key, val, err := keysToVal(rawMemStat)
if err != nil {
h.logger.Printf("[ERR] driver.lxc: error getting stat for line %q", rawMemStat)
continue
}
if _, ok := memData[key]; ok {
memData[key] = val
}
}
ms := &cstructs.MemoryStats{
RSS: memData["rss"],
Cache: memData["cache"],
Swap: memData["swap"],
Measured: LXCMeasuredMemStats,
}
mu := h.container.CgroupItem("memory.max_usage_in_bytes")
for _, rawMemMaxUsage := range mu {
val, err := strconv.ParseUint(rawMemMaxUsage, 10, 64)
if err != nil {
h.logger.Printf("[ERR] driver.lxc: unable to get max memory usage: %v", err)
continue
}
ms.MaxUsage = val
}
ku := h.container.CgroupItem("memory.kmem.usage_in_bytes")
for _, rawKernelUsage := range ku {
val, err := strconv.ParseUint(rawKernelUsage, 10, 64)
if err != nil {
h.logger.Printf("[ERR] driver.lxc: unable to get kernel memory usage: %v", err)
continue
}
ms.KernelUsage = val
}
mku := h.container.CgroupItem("memory.kmem.max_usage_in_bytes")
for _, rawMaxKernelUsage := range mku {
val, err := strconv.ParseUint(rawMaxKernelUsage, 10, 64)
if err != nil {
h.logger.Printf("[ERR] driver.lxc: unable to get max kernel memory usage: %v", err)
continue
}
ms.KernelMaxUsage = val
}
taskResUsage := cstructs.TaskResourceUsage{
ResourceUsage: &cstructs.ResourceUsage{
CpuStats: cs,
MemoryStats: ms,
},
Timestamp: t.UTC().UnixNano(),
}
return &taskResUsage, nil
}
func (h *lxcDriverHandle) run() {
defer close(h.waitCh)
timer := time.NewTimer(containerMonitorIntv)
for {
select {
case <-timer.C:
process, err := os.FindProcess(h.initPid)
if err != nil {
h.waitCh <- &dstructs.WaitResult{Err: err}
return
}
if err := process.Signal(syscall.Signal(0)); err != nil {
h.waitCh <- &dstructs.WaitResult{}
return
}
timer.Reset(containerMonitorIntv)
case <-h.doneCh:
h.waitCh <- &dstructs.WaitResult{}
return
}
}
}
func keysToVal(line string) (string, uint64, error) {
tokens := strings.Split(line, " ")
if len(tokens) != 2 {
return "", 0, fmt.Errorf("line isn't a k/v pair")
}
key := tokens[0]
val, err := strconv.ParseUint(tokens[1], 10, 64)
return key, val, err
}