open-nomad/client/alloc_runner.go
Alex Dadgar bddedd7aba Don't deepcopy job when retrieving copy of Alloc
This PR removes deepcopying of the job attached to the allocation in the
alloc runner. This operation is called very often so removing reflect
from the code path and the potentially large number of mallocs need to
create a job reduced memory and cpu pressure.
2017-05-01 14:50:34 -07:00

726 lines
20 KiB
Go

package client
import (
"fmt"
"log"
"os"
"path/filepath"
"sync"
"time"
"github.com/hashicorp/go-multierror"
"github.com/hashicorp/nomad/client/allocdir"
"github.com/hashicorp/nomad/client/config"
"github.com/hashicorp/nomad/client/vaultclient"
"github.com/hashicorp/nomad/nomad/structs"
cstructs "github.com/hashicorp/nomad/client/structs"
)
const (
// taskReceivedSyncLimit is how long the client will wait before sending
// that a task was received to the server. The client does not immediately
// send that the task was received to the server because another transition
// to running or failed is likely to occur immediately after and a single
// update will transfer all past state information. If not other transition
// has occurred up to this limit, we will send to the server.
taskReceivedSyncLimit = 30 * time.Second
)
// AllocStateUpdater is used to update the status of an allocation
type AllocStateUpdater func(alloc *structs.Allocation)
type AllocStatsReporter interface {
LatestAllocStats(taskFilter string) (*cstructs.AllocResourceUsage, error)
}
// AllocRunner is used to wrap an allocation and provide the execution context.
type AllocRunner struct {
config *config.Config
updater AllocStateUpdater
logger *log.Logger
alloc *structs.Allocation
allocClientStatus string // Explicit status of allocation. Set when there are failures
allocClientDescription string
allocLock sync.Mutex
dirtyCh chan struct{}
allocDir *allocdir.AllocDir
allocDirLock sync.Mutex
tasks map[string]*TaskRunner
taskStates map[string]*structs.TaskState
restored map[string]struct{}
taskLock sync.RWMutex
taskStatusLock sync.RWMutex
updateCh chan *structs.Allocation
vaultClient vaultclient.VaultClient
consulClient ConsulServiceAPI
otherAllocDir *allocdir.AllocDir
destroy bool
destroyCh chan struct{}
destroyLock sync.Mutex
waitCh chan struct{}
// serialize saveAllocRunnerState calls
persistLock sync.Mutex
}
// allocRunnerState is used to snapshot the state of the alloc runner
type allocRunnerState struct {
Version string
Alloc *structs.Allocation
AllocDir *allocdir.AllocDir
AllocClientStatus string
AllocClientDescription string
// COMPAT: Remove in 0.7.0: removing will break upgrading directly from
// 0.5.2, so don't remove in the 0.6 series.
// Context is deprecated and only used to migrate from older releases.
// It will be removed in the future.
Context *struct {
AllocID string // unused; included for completeness
AllocDir struct {
AllocDir string
SharedDir string // unused; included for completeness
TaskDirs map[string]string
}
} `json:"Context,omitempty"`
}
// NewAllocRunner is used to create a new allocation context
func NewAllocRunner(logger *log.Logger, config *config.Config, updater AllocStateUpdater,
alloc *structs.Allocation, vaultClient vaultclient.VaultClient,
consulClient ConsulServiceAPI) *AllocRunner {
ar := &AllocRunner{
config: config,
updater: updater,
logger: logger,
alloc: alloc,
dirtyCh: make(chan struct{}, 1),
tasks: make(map[string]*TaskRunner),
taskStates: copyTaskStates(alloc.TaskStates),
restored: make(map[string]struct{}),
updateCh: make(chan *structs.Allocation, 64),
destroyCh: make(chan struct{}),
waitCh: make(chan struct{}),
vaultClient: vaultClient,
consulClient: consulClient,
}
return ar
}
// stateFilePath returns the path to our state file
func (r *AllocRunner) stateFilePath() string {
r.allocLock.Lock()
defer r.allocLock.Unlock()
path := filepath.Join(r.config.StateDir, "alloc", r.alloc.ID, "state.json")
return path
}
// RestoreState is used to restore the state of the alloc runner
func (r *AllocRunner) RestoreState() error {
// Load the snapshot
var snap allocRunnerState
if err := restoreState(r.stateFilePath(), &snap); err != nil {
return err
}
// #2132 Upgrade path: if snap.AllocDir is nil, try to convert old
// Context struct to new AllocDir struct
if snap.AllocDir == nil && snap.Context != nil {
r.logger.Printf("[DEBUG] client: migrating state snapshot for alloc %q", r.alloc.ID)
snap.AllocDir = allocdir.NewAllocDir(r.logger, snap.Context.AllocDir.AllocDir)
for taskName := range snap.Context.AllocDir.TaskDirs {
snap.AllocDir.NewTaskDir(taskName)
}
}
// Restore fields
r.alloc = snap.Alloc
r.allocDir = snap.AllocDir
r.allocClientStatus = snap.AllocClientStatus
r.allocClientDescription = snap.AllocClientDescription
var snapshotErrors multierror.Error
if r.alloc == nil {
snapshotErrors.Errors = append(snapshotErrors.Errors, fmt.Errorf("alloc_runner snapshot includes a nil allocation"))
}
if r.allocDir == nil {
snapshotErrors.Errors = append(snapshotErrors.Errors, fmt.Errorf("alloc_runner snapshot includes a nil alloc dir"))
}
if e := snapshotErrors.ErrorOrNil(); e != nil {
return e
}
r.taskStates = snap.Alloc.TaskStates
// Restore the task runners
var mErr multierror.Error
for name, state := range r.taskStates {
// Mark the task as restored.
r.restored[name] = struct{}{}
td, ok := r.allocDir.TaskDirs[name]
if !ok {
err := fmt.Errorf("failed to find task dir metadata for alloc %q task %q",
r.alloc.ID, name)
r.logger.Printf("[ERR] client: %v", err)
return err
}
task := &structs.Task{Name: name}
tr := NewTaskRunner(r.logger, r.config, r.setTaskState, td, r.Alloc(), task, r.vaultClient, r.consulClient)
r.tasks[name] = tr
// Skip tasks in terminal states.
if state.State == structs.TaskStateDead {
continue
}
if err := tr.RestoreState(); err != nil {
r.logger.Printf("[ERR] client: failed to restore state for alloc %s task '%s': %v", r.alloc.ID, name, err)
mErr.Errors = append(mErr.Errors, err)
} else if !r.alloc.TerminalStatus() {
// Only start if the alloc isn't in a terminal status.
go tr.Run()
}
}
return mErr.ErrorOrNil()
}
// GetAllocDir returns the alloc dir for the alloc runner
func (r *AllocRunner) GetAllocDir() *allocdir.AllocDir {
return r.allocDir
}
// SaveState is used to snapshot the state of the alloc runner
// if the fullSync is marked as false only the state of the Alloc Runner
// is snapshotted. If fullSync is marked as true, we snapshot
// all the Task Runners associated with the Alloc
func (r *AllocRunner) SaveState() error {
if err := r.saveAllocRunnerState(); err != nil {
return err
}
// Save state for each task
runners := r.getTaskRunners()
var mErr multierror.Error
for _, tr := range runners {
if err := r.saveTaskRunnerState(tr); err != nil {
mErr.Errors = append(mErr.Errors, err)
}
}
return mErr.ErrorOrNil()
}
func (r *AllocRunner) saveAllocRunnerState() error {
r.persistLock.Lock()
defer r.persistLock.Unlock()
// Create the snapshot.
alloc := r.Alloc()
r.allocLock.Lock()
allocClientStatus := r.allocClientStatus
allocClientDescription := r.allocClientDescription
r.allocLock.Unlock()
r.allocDirLock.Lock()
allocDir := r.allocDir
r.allocDirLock.Unlock()
snap := allocRunnerState{
Version: r.config.Version,
Alloc: alloc,
AllocDir: allocDir,
AllocClientStatus: allocClientStatus,
AllocClientDescription: allocClientDescription,
}
return persistState(r.stateFilePath(), &snap)
}
func (r *AllocRunner) saveTaskRunnerState(tr *TaskRunner) error {
if err := tr.SaveState(); err != nil {
return fmt.Errorf("failed to save state for alloc %s task '%s': %v",
r.alloc.ID, tr.task.Name, err)
}
return nil
}
// DestroyState is used to cleanup after ourselves
func (r *AllocRunner) DestroyState() error {
return os.RemoveAll(filepath.Dir(r.stateFilePath()))
}
// DestroyContext is used to destroy the context
func (r *AllocRunner) DestroyContext() error {
return r.allocDir.Destroy()
}
// copyTaskStates returns a copy of the passed task states.
func copyTaskStates(states map[string]*structs.TaskState) map[string]*structs.TaskState {
copy := make(map[string]*structs.TaskState, len(states))
for task, state := range states {
copy[task] = state.Copy()
}
return copy
}
// Alloc returns the associated allocation
func (r *AllocRunner) Alloc() *structs.Allocation {
r.allocLock.Lock()
// Clear the job before copying
job := r.alloc.Job
r.alloc.Job = nil
alloc := r.alloc.Copy()
// Restore
r.alloc.Job = job
alloc.Job = job
// The status has explicitly been set.
if r.allocClientStatus != "" || r.allocClientDescription != "" {
alloc.ClientStatus = r.allocClientStatus
alloc.ClientDescription = r.allocClientDescription
// Copy over the task states so we don't lose them
r.taskStatusLock.RLock()
alloc.TaskStates = copyTaskStates(r.taskStates)
r.taskStatusLock.RUnlock()
r.allocLock.Unlock()
return alloc
}
r.allocLock.Unlock()
// Scan the task states to determine the status of the alloc
var pending, running, dead, failed bool
r.taskStatusLock.RLock()
alloc.TaskStates = copyTaskStates(r.taskStates)
for _, state := range r.taskStates {
switch state.State {
case structs.TaskStateRunning:
running = true
case structs.TaskStatePending:
pending = true
case structs.TaskStateDead:
if state.Failed {
failed = true
} else {
dead = true
}
}
}
r.taskStatusLock.RUnlock()
// Determine the alloc status
if failed {
alloc.ClientStatus = structs.AllocClientStatusFailed
} else if running {
alloc.ClientStatus = structs.AllocClientStatusRunning
} else if pending {
alloc.ClientStatus = structs.AllocClientStatusPending
} else if dead {
alloc.ClientStatus = structs.AllocClientStatusComplete
}
return alloc
}
// dirtySyncState is used to watch for state being marked dirty to sync
func (r *AllocRunner) dirtySyncState() {
for {
select {
case <-r.dirtyCh:
r.syncStatus()
case <-r.destroyCh:
return
}
}
}
// syncStatus is used to run and sync the status when it changes
func (r *AllocRunner) syncStatus() error {
// Get a copy of our alloc, update status server side and sync to disk
alloc := r.Alloc()
r.updater(alloc)
return r.saveAllocRunnerState()
}
// setStatus is used to update the allocation status
func (r *AllocRunner) setStatus(status, desc string) {
r.allocLock.Lock()
r.allocClientStatus = status
r.allocClientDescription = desc
r.allocLock.Unlock()
select {
case r.dirtyCh <- struct{}{}:
default:
}
}
// setTaskState is used to set the status of a task. If state is empty then the
// event is appended but not synced with the server. The event may be omitted
func (r *AllocRunner) setTaskState(taskName, state string, event *structs.TaskEvent) {
r.taskStatusLock.Lock()
defer r.taskStatusLock.Unlock()
taskState, ok := r.taskStates[taskName]
if !ok {
taskState = &structs.TaskState{}
r.taskStates[taskName] = taskState
}
// Set the tasks state.
if event != nil {
if event.FailsTask {
taskState.Failed = true
}
r.appendTaskEvent(taskState, event)
}
if state == "" {
return
}
switch state {
case structs.TaskStateRunning:
// Capture the start time if it is just starting
if taskState.State != structs.TaskStateRunning {
taskState.StartedAt = time.Now().UTC()
}
case structs.TaskStateDead:
// Capture the finished time. If it has never started there is no finish
// time
if !taskState.StartedAt.IsZero() {
taskState.FinishedAt = time.Now().UTC()
}
// Find all tasks that are not the one that is dead and check if the one
// that is dead is a leader
var otherTaskRunners []*TaskRunner
var otherTaskNames []string
leader := false
for task, tr := range r.tasks {
if task != taskName {
otherTaskRunners = append(otherTaskRunners, tr)
otherTaskNames = append(otherTaskNames, task)
} else if tr.task.Leader {
leader = true
}
}
// If the task failed, we should kill all the other tasks in the task group.
if taskState.Failed {
for _, tr := range otherTaskRunners {
tr.Destroy(structs.NewTaskEvent(structs.TaskSiblingFailed).SetFailedSibling(taskName))
}
if len(otherTaskRunners) > 0 {
r.logger.Printf("[DEBUG] client: task %q failed, destroying other tasks in task group: %v", taskName, otherTaskNames)
}
} else if leader {
// If the task was a leader task we should kill all the other tasks.
for _, tr := range otherTaskRunners {
tr.Destroy(structs.NewTaskEvent(structs.TaskLeaderDead))
}
if len(otherTaskRunners) > 0 {
r.logger.Printf("[DEBUG] client: leader task %q is dead, destroying other tasks in task group: %v", taskName, otherTaskNames)
}
}
}
// Store the new state
taskState.State = state
select {
case r.dirtyCh <- struct{}{}:
default:
}
}
// appendTaskEvent updates the task status by appending the new event.
func (r *AllocRunner) appendTaskEvent(state *structs.TaskState, event *structs.TaskEvent) {
capacity := 10
if state.Events == nil {
state.Events = make([]*structs.TaskEvent, 0, capacity)
}
// If we hit capacity, then shift it.
if len(state.Events) == capacity {
old := state.Events
state.Events = make([]*structs.TaskEvent, 0, capacity)
state.Events = append(state.Events, old[1:]...)
}
state.Events = append(state.Events, event)
}
// Run is a long running goroutine used to manage an allocation
func (r *AllocRunner) Run() {
defer close(r.waitCh)
go r.dirtySyncState()
// Find the task group to run in the allocation
alloc := r.alloc
tg := alloc.Job.LookupTaskGroup(alloc.TaskGroup)
if tg == nil {
r.logger.Printf("[ERR] client: alloc '%s' for missing task group '%s'", alloc.ID, alloc.TaskGroup)
r.setStatus(structs.AllocClientStatusFailed, fmt.Sprintf("missing task group '%s'", alloc.TaskGroup))
return
}
// Create the execution context
r.allocDirLock.Lock()
if r.allocDir == nil {
// Build allocation directory
r.allocDir = allocdir.NewAllocDir(r.logger, filepath.Join(r.config.AllocDir, r.alloc.ID))
if err := r.allocDir.Build(); err != nil {
r.logger.Printf("[WARN] client: failed to build task directories: %v", err)
r.setStatus(structs.AllocClientStatusFailed, fmt.Sprintf("failed to build task dirs for '%s'", alloc.TaskGroup))
r.allocDirLock.Unlock()
return
}
if r.otherAllocDir != nil {
if err := r.allocDir.Move(r.otherAllocDir, tg.Tasks); err != nil {
r.logger.Printf("[ERROR] client: failed to move alloc dir into alloc %q: %v", r.alloc.ID, err)
}
if err := r.otherAllocDir.Destroy(); err != nil {
r.logger.Printf("[ERROR] client: error destroying allocdir %v: %v", r.otherAllocDir.AllocDir, err)
}
}
}
r.allocDirLock.Unlock()
// Check if the allocation is in a terminal status. In this case, we don't
// start any of the task runners and directly wait for the destroy signal to
// clean up the allocation.
if alloc.TerminalStatus() {
r.logger.Printf("[DEBUG] client: alloc %q in terminal status, waiting for destroy", r.alloc.ID)
r.handleDestroy()
r.logger.Printf("[DEBUG] client: terminating runner for alloc '%s'", r.alloc.ID)
return
}
// Start the task runners
r.logger.Printf("[DEBUG] client: starting task runners for alloc '%s'", r.alloc.ID)
r.taskLock.Lock()
for _, task := range tg.Tasks {
if _, ok := r.restored[task.Name]; ok {
continue
}
r.allocDirLock.Lock()
taskdir := r.allocDir.NewTaskDir(task.Name)
r.allocDirLock.Unlock()
tr := NewTaskRunner(r.logger, r.config, r.setTaskState, taskdir, r.Alloc(), task.Copy(), r.vaultClient, r.consulClient)
r.tasks[task.Name] = tr
tr.MarkReceived()
go tr.Run()
}
r.taskLock.Unlock()
// taskDestroyEvent contains an event that caused the destroyment of a task
// in the allocation.
var taskDestroyEvent *structs.TaskEvent
OUTER:
// Wait for updates
for {
select {
case update := <-r.updateCh:
// Store the updated allocation.
r.allocLock.Lock()
r.alloc = update
r.allocLock.Unlock()
// Check if we're in a terminal status
if update.TerminalStatus() {
taskDestroyEvent = structs.NewTaskEvent(structs.TaskKilled)
break OUTER
}
// Update the task groups
runners := r.getTaskRunners()
for _, tr := range runners {
tr.Update(update)
}
case <-r.destroyCh:
taskDestroyEvent = structs.NewTaskEvent(structs.TaskKilled)
break OUTER
}
}
// Kill the task runners
r.destroyTaskRunners(taskDestroyEvent)
// Block until we should destroy the state of the alloc
r.handleDestroy()
r.logger.Printf("[DEBUG] client: terminating runner for alloc '%s'", r.alloc.ID)
}
// SetPreviousAllocDir sets the previous allocation directory of the current
// allocation
func (r *AllocRunner) SetPreviousAllocDir(allocDir *allocdir.AllocDir) {
r.otherAllocDir = allocDir
}
// destroyTaskRunners destroys the task runners, waits for them to terminate and
// then saves state.
func (r *AllocRunner) destroyTaskRunners(destroyEvent *structs.TaskEvent) {
// Destroy each sub-task
runners := r.getTaskRunners()
for _, tr := range runners {
tr.Destroy(destroyEvent)
}
// Wait for termination of the task runners
for _, tr := range runners {
<-tr.WaitCh()
}
}
// handleDestroy blocks till the AllocRunner should be destroyed and does the
// necessary cleanup.
func (r *AllocRunner) handleDestroy() {
// Final state sync. We do this to ensure that the server has the correct
// state as we wait for a destroy.
r.syncStatus()
for {
select {
case <-r.destroyCh:
if err := r.DestroyContext(); err != nil {
r.logger.Printf("[ERR] client: failed to destroy context for alloc '%s': %v",
r.alloc.ID, err)
}
if err := r.DestroyState(); err != nil {
r.logger.Printf("[ERR] client: failed to destroy state for alloc '%s': %v",
r.alloc.ID, err)
}
return
case <-r.updateCh:
r.logger.Printf("[ERR] client: dropping update to terminal alloc '%s'", r.alloc.ID)
}
}
}
// Update is used to update the allocation of the context
func (r *AllocRunner) Update(update *structs.Allocation) {
select {
case r.updateCh <- update:
default:
r.logger.Printf("[ERR] client: dropping update to alloc '%s'", update.ID)
}
}
// StatsReporter returns an interface to query resource usage statistics of an
// allocation
func (r *AllocRunner) StatsReporter() AllocStatsReporter {
return r
}
// getTaskRunners is a helper that returns a copy of the task runners list using
// the taskLock.
func (r *AllocRunner) getTaskRunners() []*TaskRunner {
// Get the task runners
r.taskLock.RLock()
defer r.taskLock.RUnlock()
runners := make([]*TaskRunner, 0, len(r.tasks))
for _, tr := range r.tasks {
runners = append(runners, tr)
}
return runners
}
// LatestAllocStats returns the latest allocation stats. If the optional taskFilter is set
// the allocation stats will only include the given task.
func (r *AllocRunner) LatestAllocStats(taskFilter string) (*cstructs.AllocResourceUsage, error) {
astat := &cstructs.AllocResourceUsage{
Tasks: make(map[string]*cstructs.TaskResourceUsage),
}
var flat []*cstructs.TaskResourceUsage
if taskFilter != "" {
r.taskLock.RLock()
tr, ok := r.tasks[taskFilter]
r.taskLock.RUnlock()
if !ok {
return nil, fmt.Errorf("allocation %q has no task %q", r.alloc.ID, taskFilter)
}
l := tr.LatestResourceUsage()
if l != nil {
astat.Tasks[taskFilter] = l
flat = []*cstructs.TaskResourceUsage{l}
astat.Timestamp = l.Timestamp
}
} else {
// Get the task runners
runners := r.getTaskRunners()
for _, tr := range runners {
l := tr.LatestResourceUsage()
if l != nil {
astat.Tasks[tr.task.Name] = l
flat = append(flat, l)
if l.Timestamp > astat.Timestamp {
astat.Timestamp = l.Timestamp
}
}
}
}
astat.ResourceUsage = sumTaskResourceUsage(flat)
return astat, nil
}
// sumTaskResourceUsage takes a set of task resources and sums their resources
func sumTaskResourceUsage(usages []*cstructs.TaskResourceUsage) *cstructs.ResourceUsage {
summed := &cstructs.ResourceUsage{
MemoryStats: &cstructs.MemoryStats{},
CpuStats: &cstructs.CpuStats{},
}
for _, usage := range usages {
summed.Add(usage.ResourceUsage)
}
return summed
}
// shouldUpdate takes the AllocModifyIndex of an allocation sent from the server and
// checks if the current running allocation is behind and should be updated.
func (r *AllocRunner) shouldUpdate(serverIndex uint64) bool {
r.allocLock.Lock()
defer r.allocLock.Unlock()
return r.alloc.AllocModifyIndex < serverIndex
}
// Destroy is used to indicate that the allocation context should be destroyed
func (r *AllocRunner) Destroy() {
r.destroyLock.Lock()
defer r.destroyLock.Unlock()
if r.destroy {
return
}
r.destroy = true
close(r.destroyCh)
}
// WaitCh returns a channel to wait for termination
func (r *AllocRunner) WaitCh() <-chan struct{} {
return r.waitCh
}