package exec2
import (
"context"
"fmt"
"os"
"runtime"
"sync"
"time"
"github.com/hashicorp/consul-template/signals"
hclog "github.com/hashicorp/go-hclog"
"github.com/hashicorp/nomad/client/lib/cgutil"
"github.com/hashicorp/nomad/drivers/shared/capabilities"
"github.com/hashicorp/nomad/drivers/shared/eventer"
"github.com/Alexis211/nomad-driver-exec2/executor"
"github.com/hashicorp/nomad/drivers/shared/resolvconf"
"github.com/hashicorp/nomad/helper/pluginutils/hclutils"
"github.com/hashicorp/nomad/helper/pluginutils/loader"
"github.com/hashicorp/nomad/helper/pointer"
"github.com/hashicorp/nomad/plugins/base"
"github.com/hashicorp/nomad/plugins/drivers"
"github.com/hashicorp/nomad/plugins/drivers/utils"
"github.com/hashicorp/nomad/plugins/shared/hclspec"
pstructs "github.com/hashicorp/nomad/plugins/shared/structs"
)
const (
// pluginName is the name of the plugin
pluginName = "exec2"
// fingerprintPeriod is the interval at which the driver will send fingerprint responses
fingerprintPeriod = 30 * time.Second
// taskHandleVersion is the version of task handle which this driver sets
// and understands how to decode driver state
taskHandleVersion = 1
)
var (
// PluginID is the exec plugin metadata registered in the plugin
// catalog.
PluginID = loader.PluginID{
Name: pluginName,
PluginType: base.PluginTypeDriver,
}
// pluginInfo is the response returned for the PluginInfo RPC
pluginInfo = &base.PluginInfoResponse{
Type: base.PluginTypeDriver,
PluginApiVersions: []string{drivers.ApiVersion010},
PluginVersion: "0.1.0",
Name: pluginName,
}
// configSpec is the hcl specification returned by the ConfigSchema RPC
configSpec = hclspec.NewObject(map[string]*hclspec.Spec{
"no_pivot_root": hclspec.NewDefault(
hclspec.NewAttr("no_pivot_root", "bool", false),
hclspec.NewLiteral("false"),
),
"default_pid_mode": hclspec.NewDefault(
hclspec.NewAttr("default_pid_mode", "string", false),
hclspec.NewLiteral(`"private"`),
),
"default_ipc_mode": hclspec.NewDefault(
hclspec.NewAttr("default_ipc_mode", "string", false),
hclspec.NewLiteral(`"private"`),
),
"allow_caps": hclspec.NewDefault(
hclspec.NewAttr("allow_caps", "list(string)", false),
hclspec.NewLiteral(capabilities.HCLSpecLiteral),
),
// Default host directories to bind in tasks
"bind": hclspec.NewDefault(
hclspec.NewAttr("bind", "list(map(string))", false),
hclspec.NewLiteral("{}"),
),
"bind_read_only": hclspec.NewDefault(
hclspec.NewAttr("bind_read_only", "list(map(string))", false),
hclspec.NewLiteral("{}"),
),
})
// taskConfigSpec is the hcl specification for the driver config section of
// a task within a job. It is returned in the TaskConfigSchema RPC
taskConfigSpec = hclspec.NewObject(map[string]*hclspec.Spec{
"command": hclspec.NewAttr("command", "string", true),
"args": hclspec.NewAttr("args", "list(string)", false),
"bind": hclspec.NewAttr("bind", "list(map(string))", false),
"bind_read_only": hclspec.NewAttr("bind_read_only", "list(map(string))", false),
"pid_mode": hclspec.NewAttr("pid_mode", "string", false),
"ipc_mode": hclspec.NewAttr("ipc_mode", "string", false),
"cap_add": hclspec.NewAttr("cap_add", "list(string)", false),
"cap_drop": hclspec.NewAttr("cap_drop", "list(string)", false),
})
// driverCapabilities represents the RPC response for what features are
// implemented by the exec task driver
driverCapabilities = &drivers.Capabilities{
SendSignals: true,
Exec: true,
FSIsolation: drivers.FSIsolationNone,
NetIsolationModes: []drivers.NetIsolationMode{
drivers.NetIsolationModeHost,
drivers.NetIsolationModeGroup,
},
MountConfigs: drivers.MountConfigSupportAll,
}
)
// Driver fork/execs tasks using many of the underlying OS's isolation
// features where configured.
type Driver struct {
// eventer is used to handle multiplexing of TaskEvents calls such that an
// event can be broadcast to all callers
eventer *eventer.Eventer
// config is the driver configuration set by the SetConfig RPC
config Config
// tasks is the in memory datastore mapping taskIDs to driverHandles
tasks *taskStore
// ctx is the context for the driver. It is passed to other subsystems to
// coordinate shutdown
ctx context.Context
// signalShutdown is called when the driver is shutting down and cancels
// the ctx passed to any subsystems
signalShutdown context.CancelFunc
// logger will log to the Nomad agent
logger hclog.Logger
// A tri-state boolean to know if the fingerprinting has happened and
// whether it has been successful
fingerprintSuccess *bool
fingerprintLock sync.Mutex
}
// Config is the driver configuration set by the SetConfig RPC call
type Config struct {
// NoPivotRoot disables the use of pivot_root, useful when the root partition
// is on ramdisk
NoPivotRoot bool `codec:"no_pivot_root"`
// DefaultModePID is the default PID isolation set for all tasks using
// exec-based task drivers.
DefaultModePID string `codec:"default_pid_mode"`
// DefaultModeIPC is the default IPC isolation set for all tasks using
// exec-based task drivers.
DefaultModeIPC string `codec:"default_ipc_mode"`
// AllowCaps configures which Linux Capabilities are enabled for tasks
// running on this node.
AllowCaps []string `codec:"allow_caps"`
// Paths to bind for read-write acess in all jobs
Bind hclutils.MapStrStr `codec:"bind"`
// Paths to bind for read-only acess in all jobs
BindReadOnly hclutils.MapStrStr `codec:"bind_read_only"`
}
func (c *Config) validate() error {
switch c.DefaultModePID {
case executor.IsolationModePrivate, executor.IsolationModeHost:
default:
return fmt.Errorf("default_pid_mode must be %q or %q, got %q", executor.IsolationModePrivate, executor.IsolationModeHost, c.DefaultModePID)
}
switch c.DefaultModeIPC {
case executor.IsolationModePrivate, executor.IsolationModeHost:
default:
return fmt.Errorf("default_ipc_mode must be %q or %q, got %q", executor.IsolationModePrivate, executor.IsolationModeHost, c.DefaultModeIPC)
}
badCaps := capabilities.Supported().Difference(capabilities.New(c.AllowCaps))
if !badCaps.Empty() {
return fmt.Errorf("allow_caps configured with capabilities not supported by system: %s", badCaps)
}
return nil
}
// TaskConfig is the driver configuration of a task within a job
type TaskConfig struct {
// Command is the thing to exec.
Command string `codec:"command"`
// Args are passed along to Command.
Args []string `codec:"args"`
// Paths to bind for read-write acess
Bind hclutils.MapStrStr `codec:"bind"`
// Paths to bind for read-only acess
BindReadOnly hclutils.MapStrStr `codec:"bind_read_only"`
// ModePID indicates whether PID namespace isolation is enabled for the task.
// Must be "private" or "host" if set.
ModePID string `codec:"pid_mode"`
// ModeIPC indicates whether IPC namespace isolation is enabled for the task.
// Must be "private" or "host" if set.
ModeIPC string `codec:"ipc_mode"`
// CapAdd is a set of linux capabilities to enable.
CapAdd []string `codec:"cap_add"`
// CapDrop is a set of linux capabilities to disable.
CapDrop []string `codec:"cap_drop"`
}
func (tc *TaskConfig) validate() error {
switch tc.ModePID {
case "", executor.IsolationModePrivate, executor.IsolationModeHost:
default:
return fmt.Errorf("pid_mode must be %q or %q, got %q", executor.IsolationModePrivate, executor.IsolationModeHost, tc.ModePID)
}
switch tc.ModeIPC {
case "", executor.IsolationModePrivate, executor.IsolationModeHost:
default:
return fmt.Errorf("ipc_mode must be %q or %q, got %q", executor.IsolationModePrivate, executor.IsolationModeHost, tc.ModeIPC)
}
supported := capabilities.Supported()
badAdds := supported.Difference(capabilities.New(tc.CapAdd))
if !badAdds.Empty() {
return fmt.Errorf("cap_add configured with capabilities not supported by system: %s", badAdds)
}
badDrops := supported.Difference(capabilities.New(tc.CapDrop))
if !badDrops.Empty() {
return fmt.Errorf("cap_drop configured with capabilities not supported by system: %s", badDrops)
}
return nil
}
// TaskState is the state which is encoded in the handle returned in
// StartTask. This information is needed to rebuild the task state and handler
// during recovery.
type TaskState struct {
TaskConfig *drivers.TaskConfig
Pid int
StartedAt time.Time
}
// NewPlugin returns a new DrivePlugin implementation
func NewPlugin(logger hclog.Logger) drivers.DriverPlugin {
ctx, cancel := context.WithCancel(context.Background())
logger = logger.Named(pluginName)
return &Driver{
eventer: eventer.NewEventer(ctx, logger),
tasks: newTaskStore(),
ctx: ctx,
signalShutdown: cancel,
logger: logger,
}
}
// setFingerprintSuccess marks the driver as having fingerprinted successfully
func (d *Driver) setFingerprintSuccess() {
d.fingerprintLock.Lock()
d.fingerprintSuccess = pointer.Of(true)
d.fingerprintLock.Unlock()
}
// setFingerprintFailure marks the driver as having failed fingerprinting
func (d *Driver) setFingerprintFailure() {
d.fingerprintLock.Lock()
d.fingerprintSuccess = pointer.Of(false)
d.fingerprintLock.Unlock()
}
// fingerprintSuccessful returns true if the driver has
// never fingerprinted or has successfully fingerprinted
func (d *Driver) fingerprintSuccessful() bool {
d.fingerprintLock.Lock()
defer d.fingerprintLock.Unlock()
return d.fingerprintSuccess == nil || *d.fingerprintSuccess
}
func (d *Driver) PluginInfo() (*base.PluginInfoResponse, error) {
return pluginInfo, nil
}
func (d *Driver) ConfigSchema() (*hclspec.Spec, error) {
return configSpec, nil
}
func (d *Driver) SetConfig(cfg *base.Config) error {
// unpack, validate, and set agent plugin config
var config Config
if len(cfg.PluginConfig) != 0 {
if err := base.MsgPackDecode(cfg.PluginConfig, &config); err != nil {
return err
}
}
if err := config.validate(); err != nil {
return err
}
d.logger.Info("Got config", "driver_config", hclog.Fmt("%+v", config))
d.config = config
return nil
}
func (d *Driver) TaskConfigSchema() (*hclspec.Spec, error) {
return taskConfigSpec, nil
}
// Capabilities is returned by the Capabilities RPC and indicates what
// optional features this driver supports
func (d *Driver) Capabilities() (*drivers.Capabilities, error) {
return driverCapabilities, nil
}
func (d *Driver) Fingerprint(ctx context.Context) (<-chan *drivers.Fingerprint, error) {
ch := make(chan *drivers.Fingerprint)
go d.handleFingerprint(ctx, ch)
return ch, nil
}
func (d *Driver) handleFingerprint(ctx context.Context, ch chan<- *drivers.Fingerprint) {
defer close(ch)
ticker := time.NewTimer(0)
for {
select {
case <-ctx.Done():
return
case <-d.ctx.Done():
return
case <-ticker.C:
ticker.Reset(fingerprintPeriod)
ch <- d.buildFingerprint()
}
}
}
func (d *Driver) buildFingerprint() *drivers.Fingerprint {
if runtime.GOOS != "linux" {
d.setFingerprintFailure()
return &drivers.Fingerprint{
Health: drivers.HealthStateUndetected,
HealthDescription: "exec driver unsupported on client OS",
}
}
fp := &drivers.Fingerprint{
Attributes: map[string]*pstructs.Attribute{},
Health: drivers.HealthStateHealthy,
HealthDescription: drivers.DriverHealthy,
}
if !utils.IsUnixRoot() {
fp.Health = drivers.HealthStateUndetected
fp.HealthDescription = drivers.DriverRequiresRootMessage
d.setFingerprintFailure()
return fp
}
mount, err := cgutil.FindCgroupMountpointDir()
if err != nil {
fp.Health = drivers.HealthStateUnhealthy
fp.HealthDescription = drivers.NoCgroupMountMessage
if d.fingerprintSuccessful() {
d.logger.Warn(fp.HealthDescription, "error", err)
}
d.setFingerprintFailure()
return fp
}
if mount == "" {
fp.Health = drivers.HealthStateUnhealthy
fp.HealthDescription = drivers.CgroupMountEmpty
d.setFingerprintFailure()
return fp
}
fp.Attributes["driver.exec"] = pstructs.NewBoolAttribute(true)
d.setFingerprintSuccess()
return fp
}
func (d *Driver) RecoverTask(handle *drivers.TaskHandle) error {
if handle == nil {
return fmt.Errorf("handle cannot be nil")
}
// If already attached to handle there's nothing to recover.
if _, ok := d.tasks.Get(handle.Config.ID); ok {
d.logger.Trace("nothing to recover; task already exists",
"task_id", handle.Config.ID,
"task_name", handle.Config.Name,
)
return nil
}
// Handle doesn't already exist, try to reattach
var taskState TaskState
if err := handle.GetDriverState(&taskState); err != nil {
d.logger.Error("failed to decode task state from handle", "error", err, "task_id", handle.Config.ID)
return fmt.Errorf("failed to decode task state from handle: %v", err)
}
// Create new executor
exec := executor.NewExecutorWithIsolation(
d.logger.With("task_name", handle.Config.Name, "alloc_id", handle.Config.AllocID),)
h := &taskHandle{
exec: exec,
pid: taskState.Pid,
taskConfig: taskState.TaskConfig,
procState: drivers.TaskStateRunning,
startedAt: taskState.StartedAt,
exitResult: &drivers.ExitResult{},
logger: d.logger,
}
d.tasks.Set(taskState.TaskConfig.ID, h)
go h.run()
return nil
}
func (d *Driver) StartTask(cfg *drivers.TaskConfig) (*drivers.TaskHandle, *drivers.DriverNetwork, error) {
if _, ok := d.tasks.Get(cfg.ID); ok {
return nil, nil, fmt.Errorf("task with ID %q already started", cfg.ID)
}
var driverConfig TaskConfig
if err := cfg.DecodeDriverConfig(&driverConfig); err != nil {
return nil, nil, fmt.Errorf("failed to decode driver config: %v", err)
}
if err := driverConfig.validate(); err != nil {
return nil, nil, fmt.Errorf("failed driver config validation: %v", err)
}
d.logger.Info("starting task", "driver_cfg", hclog.Fmt("%+v", driverConfig))
handle := drivers.NewTaskHandle(taskHandleVersion)
handle.Config = cfg
exec := executor.NewExecutorWithIsolation(
d.logger.With("task_name", handle.Config.Name, "alloc_id", handle.Config.AllocID),)
user := cfg.User
if user == "" {
user = "0"
}
if cfg.DNS != nil {
dnsMount, err := resolvconf.GenerateDNSMount(cfg.TaskDir().Dir, cfg.DNS)
if err != nil {
return nil, nil, fmt.Errorf("failed to build mount for resolv.conf: %v", err)
}
cfg.Mounts = append(cfg.Mounts, dnsMount)
}
// Bind mounts specified in driver config
if d.config.Bind != nil {
for host, task := range d.config.Bind {
mount_config := drivers.MountConfig{
TaskPath: task,
HostPath: host,
Readonly: false,
PropagationMode: "private",
}
d.logger.Info("adding RW mount from driver config", "mount_config", hclog.Fmt("%+v", mount_config))
cfg.Mounts = append(cfg.Mounts, &mount_config)
}
}
if d.config.BindReadOnly != nil {
for host, task := range d.config.BindReadOnly {
mount_config := drivers.MountConfig{
TaskPath: task,
HostPath: host,
Readonly: true,
PropagationMode: "private",
}
d.logger.Info("adding RO mount from driver config", "mount_config", hclog.Fmt("%+v", mount_config))
cfg.Mounts = append(cfg.Mounts, &mount_config)
}
}
// Bind mounts specified in task config
if driverConfig.Bind != nil {
for host, task := range driverConfig.Bind {
mount_config := drivers.MountConfig{
TaskPath: task,
HostPath: host,
Readonly: false,
PropagationMode: "private",
}
d.logger.Info("adding RW mount from task spec", "mount_config", hclog.Fmt("%+v", mount_config))
cfg.Mounts = append(cfg.Mounts, &mount_config)
}
}
if driverConfig.BindReadOnly != nil {
for host, task := range driverConfig.BindReadOnly {
mount_config := drivers.MountConfig{
TaskPath: task,
HostPath: host,
Readonly: true,
PropagationMode: "private",
}
d.logger.Info("adding RO mount from task spec", "mount_config", hclog.Fmt("%+v", mount_config))
cfg.Mounts = append(cfg.Mounts, &mount_config)
}
}
caps, err := capabilities.Calculate(
capabilities.NomadDefaults(), d.config.AllowCaps, driverConfig.CapAdd, driverConfig.CapDrop,
)
if err != nil {
return nil, nil, err
}
d.logger.Debug("task capabilities", "capabilities", caps)
execCmd := &executor.ExecCommand{
Cmd: driverConfig.Command,
Args: driverConfig.Args,
Env: cfg.EnvList(),
User: user,
ResourceLimits: true,
NoPivotRoot: d.config.NoPivotRoot,
Resources: cfg.Resources,
TaskDir: cfg.TaskDir().Dir,
StdoutPath: cfg.StdoutPath,
StderrPath: cfg.StderrPath,
Mounts: cfg.Mounts,
Devices: cfg.Devices,
NetworkIsolation: cfg.NetworkIsolation,
ModePID: executor.IsolationMode(d.config.DefaultModePID, driverConfig.ModePID),
ModeIPC: executor.IsolationMode(d.config.DefaultModeIPC, driverConfig.ModeIPC),
Capabilities: caps,
}
d.logger.Info("launching with", "exec_cmd", hclog.Fmt("%+v", execCmd))
ps, err := exec.Launch(execCmd)
if err != nil {
return nil, nil, fmt.Errorf("failed to launch command with executor: %v", err)
}
h := &taskHandle{
exec: exec,
pid: ps.Pid,
taskConfig: cfg,
procState: drivers.TaskStateRunning,
startedAt: time.Now().Round(time.Millisecond),
logger: d.logger,
}
driverState := TaskState{
Pid: ps.Pid,
TaskConfig: cfg,
StartedAt: h.startedAt,
}
if err := handle.SetDriverState(&driverState); err != nil {
d.logger.Error("failed to start task, error setting driver state", "error", err)
_ = exec.Shutdown("", 0)
return nil, nil, fmt.Errorf("failed to set driver state: %v", err)
}
d.tasks.Set(cfg.ID, h)
go h.run()
return handle, nil, nil
}
func (d *Driver) WaitTask(ctx context.Context, taskID string) (<-chan *drivers.ExitResult, error) {
handle, ok := d.tasks.Get(taskID)
if !ok {
return nil, drivers.ErrTaskNotFound
}
ch := make(chan *drivers.ExitResult)
go d.handleWait(ctx, handle, ch)
return ch, nil
}
func (d *Driver) handleWait(ctx context.Context, handle *taskHandle, ch chan *drivers.ExitResult) {
defer close(ch)
var result *drivers.ExitResult
ps, err := handle.exec.Wait(ctx)
if err != nil {
result = &drivers.ExitResult{
Err: fmt.Errorf("executor: error waiting on process: %v", err),
}
} else {
result = &drivers.ExitResult{
ExitCode: ps.ExitCode,
Signal: ps.Signal,
}
}
select {
case <-ctx.Done():
return
case <-d.ctx.Done():
return
case ch <- result:
}
}
func (d *Driver) StopTask(taskID string, timeout time.Duration, signal string) error {
handle, ok := d.tasks.Get(taskID)
if !ok {
return drivers.ErrTaskNotFound
}
if err := handle.exec.Shutdown(signal, timeout); err != nil {
return fmt.Errorf("executor Shutdown failed: %v", err)
}
return nil
}
// resetCgroup will re-create the v2 cgroup for the task after the task has been
// destroyed by libcontainer. In the case of a task restart we call DestroyTask
// which removes the cgroup - but we still need it!
//
// Ideally the cgroup management would be more unified - and we could do the creation
// on a task runner pre-start hook, eliminating the need for this hack.
func (d *Driver) resetCgroup(handle *taskHandle) {
if cgutil.UseV2 {
if handle.taskConfig.Resources != nil &&
handle.taskConfig.Resources.LinuxResources != nil &&
handle.taskConfig.Resources.LinuxResources.CpusetCgroupPath != "" {
err := os.Mkdir(handle.taskConfig.Resources.LinuxResources.CpusetCgroupPath, 0755)
if err != nil {
d.logger.Trace("failed to reset cgroup", "path", handle.taskConfig.Resources.LinuxResources.CpusetCgroupPath)
}
}
}
}
func (d *Driver) DestroyTask(taskID string, force bool) error {
handle, ok := d.tasks.Get(taskID)
if !ok {
return drivers.ErrTaskNotFound
}
if handle.IsRunning() && !force {
return fmt.Errorf("cannot destroy running task")
}
if err := handle.exec.Shutdown("", 0); err != nil {
handle.logger.Error("destroying executor failed", "error", err)
}
// workaround for the case where DestroyTask was issued on task restart
d.resetCgroup(handle)
d.tasks.Delete(taskID)
return nil
}
func (d *Driver) InspectTask(taskID string) (*drivers.TaskStatus, error) {
handle, ok := d.tasks.Get(taskID)
if !ok {
return nil, drivers.ErrTaskNotFound
}
return handle.TaskStatus(), nil
}
func (d *Driver) TaskStats(ctx context.Context, taskID string, interval time.Duration) (<-chan *drivers.TaskResourceUsage, error) {
handle, ok := d.tasks.Get(taskID)
if !ok {
return nil, drivers.ErrTaskNotFound
}
return handle.exec.Stats(ctx, interval)
}
func (d *Driver) TaskEvents(ctx context.Context) (<-chan *drivers.TaskEvent, error) {
return d.eventer.TaskEvents(ctx)
}
func (d *Driver) SignalTask(taskID string, signal string) error {
handle, ok := d.tasks.Get(taskID)
if !ok {
return drivers.ErrTaskNotFound
}
sig := os.Interrupt
if s, ok := signals.SignalLookup[signal]; ok {
sig = s
} else {
d.logger.Warn("unknown signal to send to task, using SIGINT instead", "signal", signal, "task_id", handle.taskConfig.ID)
}
return handle.exec.Signal(sig)
}
func (d *Driver) ExecTask(taskID string, cmd []string, timeout time.Duration) (*drivers.ExecTaskResult, error) {
if len(cmd) == 0 {
return nil, fmt.Errorf("error cmd must have at least one value")
}
handle, ok := d.tasks.Get(taskID)
if !ok {
return nil, drivers.ErrTaskNotFound
}
args := []string{}
if len(cmd) > 1 {
args = cmd[1:]
}
out, exitCode, err := handle.exec.Exec(time.Now().Add(timeout), cmd[0], args)
if err != nil {
return nil, err
}
return &drivers.ExecTaskResult{
Stdout: out,
ExitResult: &drivers.ExitResult{
ExitCode: exitCode,
},
}, nil
}
var _ drivers.ExecTaskStreamingRawDriver = (*Driver)(nil)
func (d *Driver) ExecTaskStreamingRaw(ctx context.Context,
taskID string,
command []string,
tty bool,
stream drivers.ExecTaskStream) error {
if len(command) == 0 {
return fmt.Errorf("error cmd must have at least one value")
}
handle, ok := d.tasks.Get(taskID)
if !ok {
return drivers.ErrTaskNotFound
}
return handle.exec.ExecStreaming(ctx, command, tty, stream)
}