open-nomad/nomad/core_sched.go
Tim Gross 8673ea5cba csi: add empty CSI volume publication GC to scheduled core jobs (#7014)
This changeset adds a new core job `CoreJobCSIVolumePublicationGC` to
the leader's loop for scheduling core job evals. Right now this is an
empty method body without even a config file stanza. Later changesets
will implement the logic of volume publication GC.
2020-03-23 13:58:29 -04:00

715 lines
21 KiB
Go

package nomad
import (
"fmt"
"math"
"time"
log "github.com/hashicorp/go-hclog"
memdb "github.com/hashicorp/go-memdb"
version "github.com/hashicorp/go-version"
"github.com/hashicorp/nomad/nomad/state"
"github.com/hashicorp/nomad/nomad/structs"
"github.com/hashicorp/nomad/scheduler"
)
var (
// maxIdsPerReap is the maximum number of evals and allocations to reap in a
// single Raft transaction. This is to ensure that the Raft message does not
// become too large.
maxIdsPerReap = (1024 * 256) / 36 // 0.25 MB of ids.
)
// CoreScheduler is a special "scheduler" that is registered
// as "_core". It is used to run various administrative work
// across the cluster.
type CoreScheduler struct {
srv *Server
snap *state.StateSnapshot
logger log.Logger
}
// NewCoreScheduler is used to return a new system scheduler instance
func NewCoreScheduler(srv *Server, snap *state.StateSnapshot) scheduler.Scheduler {
s := &CoreScheduler{
srv: srv,
snap: snap,
logger: srv.logger.ResetNamed("core.sched"),
}
return s
}
// Process is used to implement the scheduler.Scheduler interface
func (c *CoreScheduler) Process(eval *structs.Evaluation) error {
switch eval.JobID {
case structs.CoreJobEvalGC:
return c.evalGC(eval)
case structs.CoreJobNodeGC:
return c.nodeGC(eval)
case structs.CoreJobJobGC:
return c.jobGC(eval)
case structs.CoreJobDeploymentGC:
return c.deploymentGC(eval)
case structs.CoreJobCSIVolumePublicationGC:
return c.csiVolumePublicationGC(eval)
case structs.CoreJobForceGC:
return c.forceGC(eval)
default:
return fmt.Errorf("core scheduler cannot handle job '%s'", eval.JobID)
}
}
// forceGC is used to garbage collect all eligible objects.
func (c *CoreScheduler) forceGC(eval *structs.Evaluation) error {
if err := c.jobGC(eval); err != nil {
return err
}
if err := c.evalGC(eval); err != nil {
return err
}
if err := c.deploymentGC(eval); err != nil {
return err
}
// Node GC must occur after the others to ensure the allocations are
// cleared.
return c.nodeGC(eval)
}
// jobGC is used to garbage collect eligible jobs.
func (c *CoreScheduler) jobGC(eval *structs.Evaluation) error {
// Get all the jobs eligible for garbage collection.
ws := memdb.NewWatchSet()
iter, err := c.snap.JobsByGC(ws, true)
if err != nil {
return err
}
var oldThreshold uint64
if eval.JobID == structs.CoreJobForceGC {
// The GC was forced, so set the threshold to its maximum so everything
// will GC.
oldThreshold = math.MaxUint64
c.logger.Debug("forced job GC")
} else {
// Get the time table to calculate GC cutoffs.
tt := c.srv.fsm.TimeTable()
cutoff := time.Now().UTC().Add(-1 * c.srv.config.JobGCThreshold)
oldThreshold = tt.NearestIndex(cutoff)
c.logger.Debug("job GC scanning before cutoff index",
"index", oldThreshold, "job_gc_threshold", c.srv.config.JobGCThreshold)
}
// Collect the allocations, evaluations and jobs to GC
var gcAlloc, gcEval []string
var gcJob []*structs.Job
OUTER:
for i := iter.Next(); i != nil; i = iter.Next() {
job := i.(*structs.Job)
// Ignore new jobs.
if job.CreateIndex > oldThreshold {
continue
}
ws := memdb.NewWatchSet()
evals, err := c.snap.EvalsByJob(ws, job.Namespace, job.ID)
if err != nil {
c.logger.Error("job GC failed to get evals for job", "job", job.ID, "error", err)
continue
}
allEvalsGC := true
var jobAlloc, jobEval []string
for _, eval := range evals {
gc, allocs, err := c.gcEval(eval, oldThreshold, true)
if err != nil {
continue OUTER
}
if gc {
jobEval = append(jobEval, eval.ID)
jobAlloc = append(jobAlloc, allocs...)
} else {
allEvalsGC = false
break
}
}
// Job is eligible for garbage collection
if allEvalsGC {
gcJob = append(gcJob, job)
gcAlloc = append(gcAlloc, jobAlloc...)
gcEval = append(gcEval, jobEval...)
}
}
// Fast-path the nothing case
if len(gcEval) == 0 && len(gcAlloc) == 0 && len(gcJob) == 0 {
return nil
}
c.logger.Debug("job GC found eligible objects",
"jobs", len(gcJob), "evals", len(gcEval), "allocs", len(gcAlloc))
// Reap the evals and allocs
if err := c.evalReap(gcEval, gcAlloc); err != nil {
return err
}
// Reap the jobs
return c.jobReap(gcJob, eval.LeaderACL)
}
// jobReap contacts the leader and issues a reap on the passed jobs
func (c *CoreScheduler) jobReap(jobs []*structs.Job, leaderACL string) error {
// Call to the leader to issue the reap
for _, req := range c.partitionJobReap(jobs, leaderACL) {
var resp structs.JobBatchDeregisterResponse
if err := c.srv.RPC("Job.BatchDeregister", req, &resp); err != nil {
c.logger.Error("batch job reap failed", "error", err)
return err
}
}
return nil
}
// partitionJobReap returns a list of JobBatchDeregisterRequests to make,
// ensuring a single request does not contain too many jobs. This is necessary
// to ensure that the Raft transaction does not become too large.
func (c *CoreScheduler) partitionJobReap(jobs []*structs.Job, leaderACL string) []*structs.JobBatchDeregisterRequest {
option := &structs.JobDeregisterOptions{Purge: true}
var requests []*structs.JobBatchDeregisterRequest
submittedJobs := 0
for submittedJobs != len(jobs) {
req := &structs.JobBatchDeregisterRequest{
Jobs: make(map[structs.NamespacedID]*structs.JobDeregisterOptions),
WriteRequest: structs.WriteRequest{
Region: c.srv.config.Region,
AuthToken: leaderACL,
},
}
requests = append(requests, req)
available := maxIdsPerReap
if remaining := len(jobs) - submittedJobs; remaining > 0 {
if remaining <= available {
for _, job := range jobs[submittedJobs:] {
jns := structs.NamespacedID{ID: job.ID, Namespace: job.Namespace}
req.Jobs[jns] = option
}
submittedJobs += remaining
} else {
for _, job := range jobs[submittedJobs : submittedJobs+available] {
jns := structs.NamespacedID{ID: job.ID, Namespace: job.Namespace}
req.Jobs[jns] = option
}
submittedJobs += available
}
}
}
return requests
}
// evalGC is used to garbage collect old evaluations
func (c *CoreScheduler) evalGC(eval *structs.Evaluation) error {
// Iterate over the evaluations
ws := memdb.NewWatchSet()
iter, err := c.snap.Evals(ws)
if err != nil {
return err
}
var oldThreshold uint64
if eval.JobID == structs.CoreJobForceGC {
// The GC was forced, so set the threshold to its maximum so everything
// will GC.
oldThreshold = math.MaxUint64
c.logger.Debug("forced eval GC")
} else {
// Compute the old threshold limit for GC using the FSM
// time table. This is a rough mapping of a time to the
// Raft index it belongs to.
tt := c.srv.fsm.TimeTable()
cutoff := time.Now().UTC().Add(-1 * c.srv.config.EvalGCThreshold)
oldThreshold = tt.NearestIndex(cutoff)
c.logger.Debug("eval GC scanning before cutoff index",
"index", oldThreshold, "eval_gc_threshold", c.srv.config.EvalGCThreshold)
}
// Collect the allocations and evaluations to GC
var gcAlloc, gcEval []string
for raw := iter.Next(); raw != nil; raw = iter.Next() {
eval := raw.(*structs.Evaluation)
// The Evaluation GC should not handle batch jobs since those need to be
// garbage collected in one shot
gc, allocs, err := c.gcEval(eval, oldThreshold, false)
if err != nil {
return err
}
if gc {
gcEval = append(gcEval, eval.ID)
}
gcAlloc = append(gcAlloc, allocs...)
}
// Fast-path the nothing case
if len(gcEval) == 0 && len(gcAlloc) == 0 {
return nil
}
c.logger.Debug("eval GC found eligibile objects",
"evals", len(gcEval), "allocs", len(gcAlloc))
return c.evalReap(gcEval, gcAlloc)
}
// gcEval returns whether the eval should be garbage collected given a raft
// threshold index. The eval disqualifies for garbage collection if it or its
// allocs are not older than the threshold. If the eval should be garbage
// collected, the associated alloc ids that should also be removed are also
// returned
func (c *CoreScheduler) gcEval(eval *structs.Evaluation, thresholdIndex uint64, allowBatch bool) (
bool, []string, error) {
// Ignore non-terminal and new evaluations
if !eval.TerminalStatus() || eval.ModifyIndex > thresholdIndex {
return false, nil, nil
}
// Create a watchset
ws := memdb.NewWatchSet()
// Look up the job
job, err := c.snap.JobByID(ws, eval.Namespace, eval.JobID)
if err != nil {
return false, nil, err
}
// Get the allocations by eval
allocs, err := c.snap.AllocsByEval(ws, eval.ID)
if err != nil {
c.logger.Error("failed to get allocs for eval",
"eval_id", eval.ID, "error", err)
return false, nil, err
}
// If the eval is from a running "batch" job we don't want to garbage
// collect its allocations. If there is a long running batch job and its
// terminal allocations get GC'd the scheduler would re-run the
// allocations.
if eval.Type == structs.JobTypeBatch {
// Check if the job is running
// Can collect if:
// Job doesn't exist
// Job is Stopped and dead
// allowBatch and the job is dead
collect := false
if job == nil {
collect = true
} else if job.Status != structs.JobStatusDead {
collect = false
} else if job.Stop {
collect = true
} else if allowBatch {
collect = true
}
// We don't want to gc anything related to a job which is not dead
// If the batch job doesn't exist we can GC it regardless of allowBatch
if !collect {
// Find allocs associated with older (based on createindex) and GC them if terminal
oldAllocs := olderVersionTerminalAllocs(allocs, job)
return false, oldAllocs, nil
}
}
// Scan the allocations to ensure they are terminal and old
gcEval := true
var gcAllocIDs []string
for _, alloc := range allocs {
if !allocGCEligible(alloc, job, time.Now(), thresholdIndex) {
// Can't GC the evaluation since not all of the allocations are
// terminal
gcEval = false
} else {
// The allocation is eligible to be GC'd
gcAllocIDs = append(gcAllocIDs, alloc.ID)
}
}
return gcEval, gcAllocIDs, nil
}
// olderVersionTerminalAllocs returns terminal allocations whose job create index
// is older than the job's create index
func olderVersionTerminalAllocs(allocs []*structs.Allocation, job *structs.Job) []string {
var ret []string
for _, alloc := range allocs {
if alloc.Job != nil && alloc.Job.CreateIndex < job.CreateIndex && alloc.TerminalStatus() {
ret = append(ret, alloc.ID)
}
}
return ret
}
// evalReap contacts the leader and issues a reap on the passed evals and
// allocs.
func (c *CoreScheduler) evalReap(evals, allocs []string) error {
// Call to the leader to issue the reap
for _, req := range c.partitionEvalReap(evals, allocs) {
var resp structs.GenericResponse
if err := c.srv.RPC("Eval.Reap", req, &resp); err != nil {
c.logger.Error("eval reap failed", "error", err)
return err
}
}
return nil
}
// partitionEvalReap returns a list of EvalDeleteRequest to make, ensuring a single
// request does not contain too many allocations and evaluations. This is
// necessary to ensure that the Raft transaction does not become too large.
func (c *CoreScheduler) partitionEvalReap(evals, allocs []string) []*structs.EvalDeleteRequest {
var requests []*structs.EvalDeleteRequest
submittedEvals, submittedAllocs := 0, 0
for submittedEvals != len(evals) || submittedAllocs != len(allocs) {
req := &structs.EvalDeleteRequest{
WriteRequest: structs.WriteRequest{
Region: c.srv.config.Region,
},
}
requests = append(requests, req)
available := maxIdsPerReap
// Add the allocs first
if remaining := len(allocs) - submittedAllocs; remaining > 0 {
if remaining <= available {
req.Allocs = allocs[submittedAllocs:]
available -= remaining
submittedAllocs += remaining
} else {
req.Allocs = allocs[submittedAllocs : submittedAllocs+available]
submittedAllocs += available
// Exhausted space so skip adding evals
continue
}
}
// Add the evals
if remaining := len(evals) - submittedEvals; remaining > 0 {
if remaining <= available {
req.Evals = evals[submittedEvals:]
submittedEvals += remaining
} else {
req.Evals = evals[submittedEvals : submittedEvals+available]
submittedEvals += available
}
}
}
return requests
}
// nodeGC is used to garbage collect old nodes
func (c *CoreScheduler) nodeGC(eval *structs.Evaluation) error {
// Iterate over the evaluations
ws := memdb.NewWatchSet()
iter, err := c.snap.Nodes(ws)
if err != nil {
return err
}
var oldThreshold uint64
if eval.JobID == structs.CoreJobForceGC {
// The GC was forced, so set the threshold to its maximum so everything
// will GC.
oldThreshold = math.MaxUint64
c.logger.Debug("forced node GC")
} else {
// Compute the old threshold limit for GC using the FSM
// time table. This is a rough mapping of a time to the
// Raft index it belongs to.
tt := c.srv.fsm.TimeTable()
cutoff := time.Now().UTC().Add(-1 * c.srv.config.NodeGCThreshold)
oldThreshold = tt.NearestIndex(cutoff)
c.logger.Debug("node GC scanning before cutoff index",
"index", oldThreshold, "node_gc_threshold", c.srv.config.NodeGCThreshold)
}
// Collect the nodes to GC
var gcNode []string
OUTER:
for {
raw := iter.Next()
if raw == nil {
break
}
node := raw.(*structs.Node)
// Ignore non-terminal and new nodes
if !node.TerminalStatus() || node.ModifyIndex > oldThreshold {
continue
}
// Get the allocations by node
ws := memdb.NewWatchSet()
allocs, err := c.snap.AllocsByNode(ws, node.ID)
if err != nil {
c.logger.Error("failed to get allocs for node",
"node_id", node.ID, "error", err)
continue
}
// If there are any non-terminal allocations, skip the node. If the node
// is terminal and the allocations are not, the scheduler may not have
// run yet to transition the allocs on the node to terminal. We delay
// GC'ing until this happens.
for _, alloc := range allocs {
if !alloc.TerminalStatus() {
continue OUTER
}
}
// Node is eligible for garbage collection
gcNode = append(gcNode, node.ID)
}
// Fast-path the nothing case
if len(gcNode) == 0 {
return nil
}
c.logger.Debug("node GC found eligible nodes", "nodes", len(gcNode))
return c.nodeReap(eval, gcNode)
}
func (c *CoreScheduler) nodeReap(eval *structs.Evaluation, nodeIDs []string) error {
// For old clusters, send single deregistration messages COMPAT(0.11)
minVersionBatchNodeDeregister := version.Must(version.NewVersion("0.9.4"))
if !ServersMeetMinimumVersion(c.srv.Members(), minVersionBatchNodeDeregister, true) {
for _, id := range nodeIDs {
req := structs.NodeDeregisterRequest{
NodeID: id,
WriteRequest: structs.WriteRequest{
Region: c.srv.config.Region,
AuthToken: eval.LeaderACL,
},
}
var resp structs.NodeUpdateResponse
if err := c.srv.RPC("Node.Deregister", &req, &resp); err != nil {
c.logger.Error("node reap failed", "node_id", id, "error", err)
return err
}
}
return nil
}
// Call to the leader to issue the reap
for _, ids := range partitionAll(maxIdsPerReap, nodeIDs) {
req := structs.NodeBatchDeregisterRequest{
NodeIDs: ids,
WriteRequest: structs.WriteRequest{
Region: c.srv.config.Region,
AuthToken: eval.LeaderACL,
},
}
var resp structs.NodeUpdateResponse
if err := c.srv.RPC("Node.BatchDeregister", &req, &resp); err != nil {
c.logger.Error("node reap failed", "node_ids", ids, "error", err)
return err
}
}
return nil
}
// deploymentGC is used to garbage collect old deployments
func (c *CoreScheduler) deploymentGC(eval *structs.Evaluation) error {
// Iterate over the deployments
ws := memdb.NewWatchSet()
iter, err := c.snap.Deployments(ws)
if err != nil {
return err
}
var oldThreshold uint64
if eval.JobID == structs.CoreJobForceGC {
// The GC was forced, so set the threshold to its maximum so everything
// will GC.
oldThreshold = math.MaxUint64
c.logger.Debug("forced deployment GC")
} else {
// Compute the old threshold limit for GC using the FSM
// time table. This is a rough mapping of a time to the
// Raft index it belongs to.
tt := c.srv.fsm.TimeTable()
cutoff := time.Now().UTC().Add(-1 * c.srv.config.DeploymentGCThreshold)
oldThreshold = tt.NearestIndex(cutoff)
c.logger.Debug("deployment GC scanning before cutoff index",
"index", oldThreshold, "deployment_gc_threshold", c.srv.config.DeploymentGCThreshold)
}
// Collect the deployments to GC
var gcDeployment []string
OUTER:
for {
raw := iter.Next()
if raw == nil {
break
}
deploy := raw.(*structs.Deployment)
// Ignore non-terminal and new deployments
if deploy.Active() || deploy.ModifyIndex > oldThreshold {
continue
}
// Ensure there are no allocs referencing this deployment.
allocs, err := c.snap.AllocsByDeployment(ws, deploy.ID)
if err != nil {
c.logger.Error("failed to get allocs for deployment",
"deployment_id", deploy.ID, "error", err)
continue
}
// Ensure there is no allocation referencing the deployment.
for _, alloc := range allocs {
if !alloc.TerminalStatus() {
continue OUTER
}
}
// Deployment is eligible for garbage collection
gcDeployment = append(gcDeployment, deploy.ID)
}
// Fast-path the nothing case
if len(gcDeployment) == 0 {
return nil
}
c.logger.Debug("deployment GC found eligible deployments", "deployments", len(gcDeployment))
return c.deploymentReap(gcDeployment)
}
// deploymentReap contacts the leader and issues a reap on the passed
// deployments.
func (c *CoreScheduler) deploymentReap(deployments []string) error {
// Call to the leader to issue the reap
for _, req := range c.partitionDeploymentReap(deployments) {
var resp structs.GenericResponse
if err := c.srv.RPC("Deployment.Reap", req, &resp); err != nil {
c.logger.Error("deployment reap failed", "error", err)
return err
}
}
return nil
}
// partitionDeploymentReap returns a list of DeploymentDeleteRequest to make,
// ensuring a single request does not contain too many deployments. This is
// necessary to ensure that the Raft transaction does not become too large.
func (c *CoreScheduler) partitionDeploymentReap(deployments []string) []*structs.DeploymentDeleteRequest {
var requests []*structs.DeploymentDeleteRequest
submittedDeployments := 0
for submittedDeployments != len(deployments) {
req := &structs.DeploymentDeleteRequest{
WriteRequest: structs.WriteRequest{
Region: c.srv.config.Region,
},
}
requests = append(requests, req)
available := maxIdsPerReap
if remaining := len(deployments) - submittedDeployments; remaining > 0 {
if remaining <= available {
req.Deployments = deployments[submittedDeployments:]
submittedDeployments += remaining
} else {
req.Deployments = deployments[submittedDeployments : submittedDeployments+available]
submittedDeployments += available
}
}
}
return requests
}
// allocGCEligible returns if the allocation is eligible to be garbage collected
// according to its terminal status and its reschedule trackers
func allocGCEligible(a *structs.Allocation, job *structs.Job, gcTime time.Time, thresholdIndex uint64) bool {
// Not in a terminal status and old enough
if !a.TerminalStatus() || a.ModifyIndex > thresholdIndex {
return false
}
// If the allocation is still running on the client we can not garbage
// collect it.
if a.ClientStatus == structs.AllocClientStatusRunning {
return false
}
// If the job is deleted, stopped or dead all allocs can be removed
if job == nil || job.Stop || job.Status == structs.JobStatusDead {
return true
}
// If the allocation's desired state is Stop, it can be GCed even if it
// has failed and hasn't been rescheduled. This can happen during job updates
if a.DesiredStatus == structs.AllocDesiredStatusStop {
return true
}
// If the alloc hasn't failed then we don't need to consider it for rescheduling
// Rescheduling needs to copy over information from the previous alloc so that it
// can enforce the reschedule policy
if a.ClientStatus != structs.AllocClientStatusFailed {
return true
}
var reschedulePolicy *structs.ReschedulePolicy
tg := job.LookupTaskGroup(a.TaskGroup)
if tg != nil {
reschedulePolicy = tg.ReschedulePolicy
}
// No reschedule policy or rescheduling is disabled
if reschedulePolicy == nil || (!reschedulePolicy.Unlimited && reschedulePolicy.Attempts == 0) {
return true
}
// Restart tracking information has been carried forward
if a.NextAllocation != "" {
return true
}
// This task has unlimited rescheduling and the alloc has not been replaced, so we can't GC it yet
if reschedulePolicy.Unlimited {
return false
}
// No restarts have been attempted yet
if a.RescheduleTracker == nil || len(a.RescheduleTracker.Events) == 0 {
return false
}
// Don't GC if most recent reschedule attempt is within time interval
interval := reschedulePolicy.Interval
lastIndex := len(a.RescheduleTracker.Events)
lastRescheduleEvent := a.RescheduleTracker.Events[lastIndex-1]
timeDiff := gcTime.UTC().UnixNano() - lastRescheduleEvent.RescheduleTime
return timeDiff > interval.Nanoseconds()
}
// csiVolumeGC is used to garbage collect CSI volume publications
func (c *CoreScheduler) csiVolumePublicationGC(eval *structs.Evaluation) error {
// TODO: implement me!
c.logger.Trace("garbage collecting unclaimed CSI volume publications")
return nil
}