forked from hashicorp/nomad
/
state_store.go
782 lines (666 loc) · 19.5 KB
/
state_store.go
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package state
import (
"fmt"
"io"
"log"
"sync"
"github.com/hashicorp/go-memdb"
"github.com/hashicorp/nomad/nomad/structs"
)
// The StateStore is responsible for maintaining all the Nomad
// state. It is manipulated by the FSM which maintains consistency
// through the use of Raft. The goals of the StateStore are to provide
// high concurrency for read operations without blocking writes, and
// to provide write availability in the face of reads. EVERY object
// returned as a result of a read against the state store should be
// considered a constant and NEVER modified in place.
type StateStore struct {
logger *log.Logger
db *memdb.MemDB
watch *stateWatch
}
// StateSnapshot is used to provide a point-in-time snapshot
type StateSnapshot struct {
StateStore
}
// StateRestore is used to optimize the performance when
// restoring state by only using a single large transaction
// instead of thousands of sub transactions
type StateRestore struct {
txn *memdb.Txn
watch *stateWatch
allocNodes map[string]struct{}
}
// Abort is used to abort the restore operation
func (s *StateRestore) Abort() {
s.txn.Abort()
}
// Commit is used to commit the restore operation
func (s *StateRestore) Commit() {
s.txn.Defer(func() { s.watch.notifyAllocs(s.allocNodes) })
s.txn.Commit()
}
// IndexEntry is used with the "index" table
// for managing the latest Raft index affecting a table.
type IndexEntry struct {
Key string
Value uint64
}
// stateWatch holds shared state for watching updates. This is
// outside of StateStore so it can be shared with snapshots.
type stateWatch struct {
allocs map[string]*NotifyGroup
allocLock sync.Mutex
}
// NewStateStore is used to create a new state store
func NewStateStore(logOutput io.Writer) (*StateStore, error) {
// Create the MemDB
db, err := memdb.NewMemDB(stateStoreSchema())
if err != nil {
return nil, fmt.Errorf("state store setup failed: %v", err)
}
// Create the watch entry
watch := &stateWatch{
allocs: make(map[string]*NotifyGroup),
}
// Create the state store
s := &StateStore{
logger: log.New(logOutput, "", log.LstdFlags),
db: db,
watch: watch,
}
return s, nil
}
// Snapshot is used to create a point in time snapshot. Because
// we use MemDB, we just need to snapshot the state of the underlying
// database.
func (s *StateStore) Snapshot() (*StateSnapshot, error) {
snap := &StateSnapshot{
StateStore: StateStore{
logger: s.logger,
db: s.db.Snapshot(),
watch: s.watch,
},
}
return snap, nil
}
// Restore is used to optimize the efficiency of rebuilding
// state by minimizing the number of transactions and checking
// overhead.
func (s *StateStore) Restore() (*StateRestore, error) {
txn := s.db.Txn(true)
r := &StateRestore{
txn: txn,
watch: s.watch,
allocNodes: make(map[string]struct{}),
}
return r, nil
}
// WatchAllocs is used to subscribe a channel to changes in allocations for a node
func (s *StateStore) WatchAllocs(node string, notify chan struct{}) {
s.watch.allocLock.Lock()
defer s.watch.allocLock.Unlock()
// Check for an existing notify group
if grp, ok := s.watch.allocs[node]; ok {
grp.Wait(notify)
return
}
// Create new notify group
grp := &NotifyGroup{}
grp.Wait(notify)
s.watch.allocs[node] = grp
}
// StopWatchAllocs is used to unsubscribe a channel from changes in allocations
func (s *StateStore) StopWatchAllocs(node string, notify chan struct{}) {
s.watch.allocLock.Lock()
defer s.watch.allocLock.Unlock()
// Check for an existing notify group
if grp, ok := s.watch.allocs[node]; ok {
grp.Clear(notify)
if grp.Empty() {
delete(s.watch.allocs, node)
}
}
}
// notifyAllocs is used to notify any node alloc listeners of a change
func (w *stateWatch) notifyAllocs(nodes map[string]struct{}) {
w.allocLock.Lock()
defer w.allocLock.Unlock()
for node := range nodes {
if grp, ok := w.allocs[node]; ok {
grp.Notify()
delete(w.allocs, node)
}
}
}
// UpsertNode is used to register a node or update a node definition
// This is assumed to be triggered by the client, so we retain the value
// of drain which is set by the scheduler.
func (s *StateStore) UpsertNode(index uint64, node *structs.Node) error {
txn := s.db.Txn(true)
defer txn.Abort()
// Check if the node already exists
existing, err := txn.First("nodes", "id", node.ID)
if err != nil {
return fmt.Errorf("node lookup failed: %v", err)
}
// Setup the indexes correctly
if existing != nil {
exist := existing.(*structs.Node)
node.CreateIndex = exist.CreateIndex
node.ModifyIndex = index
node.Drain = exist.Drain // Retain the drain mode
} else {
node.CreateIndex = index
node.ModifyIndex = index
}
// Insert the node
if err := txn.Insert("nodes", node); err != nil {
return fmt.Errorf("node insert failed: %v", err)
}
if err := txn.Insert("index", &IndexEntry{"nodes", index}); err != nil {
return fmt.Errorf("index update failed: %v", err)
}
txn.Commit()
return nil
}
// DeleteNode is used to deregister a node
func (s *StateStore) DeleteNode(index uint64, nodeID string) error {
txn := s.db.Txn(true)
defer txn.Abort()
// Lookup the node
existing, err := txn.First("nodes", "id", nodeID)
if err != nil {
return fmt.Errorf("node lookup failed: %v", err)
}
if existing == nil {
return fmt.Errorf("node not found")
}
// Delete the node
if err := txn.Delete("nodes", existing); err != nil {
return fmt.Errorf("node delete failed: %v", err)
}
if err := txn.Insert("index", &IndexEntry{"nodes", index}); err != nil {
return fmt.Errorf("index update failed: %v", err)
}
txn.Commit()
return nil
}
// UpdateNodeStatus is used to update the status of a node
func (s *StateStore) UpdateNodeStatus(index uint64, nodeID, status string) error {
txn := s.db.Txn(true)
defer txn.Abort()
// Lookup the node
existing, err := txn.First("nodes", "id", nodeID)
if err != nil {
return fmt.Errorf("node lookup failed: %v", err)
}
if existing == nil {
return fmt.Errorf("node not found")
}
// Copy the existing node
existingNode := existing.(*structs.Node)
copyNode := new(structs.Node)
*copyNode = *existingNode
// Update the status in the copy
copyNode.Status = status
copyNode.ModifyIndex = index
// Insert the node
if err := txn.Insert("nodes", copyNode); err != nil {
return fmt.Errorf("node update failed: %v", err)
}
if err := txn.Insert("index", &IndexEntry{"nodes", index}); err != nil {
return fmt.Errorf("index update failed: %v", err)
}
txn.Commit()
return nil
}
// UpdateNodeDrain is used to update the drain of a node
func (s *StateStore) UpdateNodeDrain(index uint64, nodeID string, drain bool) error {
txn := s.db.Txn(true)
defer txn.Abort()
// Lookup the node
existing, err := txn.First("nodes", "id", nodeID)
if err != nil {
return fmt.Errorf("node lookup failed: %v", err)
}
if existing == nil {
return fmt.Errorf("node not found")
}
// Copy the existing node
existingNode := existing.(*structs.Node)
copyNode := new(structs.Node)
*copyNode = *existingNode
// Update the drain in the copy
copyNode.Drain = drain
copyNode.ModifyIndex = index
// Insert the node
if err := txn.Insert("nodes", copyNode); err != nil {
return fmt.Errorf("node update failed: %v", err)
}
if err := txn.Insert("index", &IndexEntry{"nodes", index}); err != nil {
return fmt.Errorf("index update failed: %v", err)
}
txn.Commit()
return nil
}
// NodeByID is used to lookup a node by ID
func (s *StateStore) NodeByID(nodeID string) (*structs.Node, error) {
txn := s.db.Txn(false)
existing, err := txn.First("nodes", "id", nodeID)
if err != nil {
return nil, fmt.Errorf("node lookup failed: %v", err)
}
if existing != nil {
return existing.(*structs.Node), nil
}
return nil, nil
}
// Nodes returns an iterator over all the nodes
func (s *StateStore) Nodes() (memdb.ResultIterator, error) {
txn := s.db.Txn(false)
// Walk the entire nodes table
iter, err := txn.Get("nodes", "id")
if err != nil {
return nil, err
}
return iter, nil
}
// UpsertJob is used to register a job or update a job definition
func (s *StateStore) UpsertJob(index uint64, job *structs.Job) error {
txn := s.db.Txn(true)
defer txn.Abort()
// Check if the job already exists
existing, err := txn.First("jobs", "id", job.ID)
if err != nil {
return fmt.Errorf("job lookup failed: %v", err)
}
// Setup the indexes correctly
if existing != nil {
job.CreateIndex = existing.(*structs.Job).CreateIndex
job.ModifyIndex = index
} else {
job.CreateIndex = index
job.ModifyIndex = index
}
// Insert the job
if err := txn.Insert("jobs", job); err != nil {
return fmt.Errorf("job insert failed: %v", err)
}
if err := txn.Insert("index", &IndexEntry{"jobs", index}); err != nil {
return fmt.Errorf("index update failed: %v", err)
}
txn.Commit()
return nil
}
// DeleteJob is used to deregister a job
func (s *StateStore) DeleteJob(index uint64, jobID string) error {
txn := s.db.Txn(true)
defer txn.Abort()
// Lookup the node
existing, err := txn.First("jobs", "id", jobID)
if err != nil {
return fmt.Errorf("job lookup failed: %v", err)
}
if existing == nil {
return fmt.Errorf("job not found")
}
// Delete the node
if err := txn.Delete("jobs", existing); err != nil {
return fmt.Errorf("job delete failed: %v", err)
}
if err := txn.Insert("index", &IndexEntry{"jobs", index}); err != nil {
return fmt.Errorf("index update failed: %v", err)
}
txn.Commit()
return nil
}
// JobByID is used to lookup a job by its ID
func (s *StateStore) JobByID(id string) (*structs.Job, error) {
txn := s.db.Txn(false)
existing, err := txn.First("jobs", "id", id)
if err != nil {
return nil, fmt.Errorf("job lookup failed: %v", err)
}
if existing != nil {
return existing.(*structs.Job), nil
}
return nil, nil
}
// Jobs returns an iterator over all the jobs
func (s *StateStore) Jobs() (memdb.ResultIterator, error) {
txn := s.db.Txn(false)
// Walk the entire jobs table
iter, err := txn.Get("jobs", "id")
if err != nil {
return nil, err
}
return iter, nil
}
// UpsertEvaluation is used to upsert an evaluation
func (s *StateStore) UpsertEvals(index uint64, evals []*structs.Evaluation) error {
txn := s.db.Txn(true)
defer txn.Abort()
// Do a nested upsert
for _, eval := range evals {
if err := s.nestedUpsertEval(txn, index, eval); err != nil {
return err
}
}
txn.Commit()
return nil
}
// nestedUpsertEvaluation is used to nest an evaluation upsert within a transaction
func (s *StateStore) nestedUpsertEval(txn *memdb.Txn, index uint64, eval *structs.Evaluation) error {
// Lookup the evaluation
existing, err := txn.First("evals", "id", eval.ID)
if err != nil {
return fmt.Errorf("eval lookup failed: %v", err)
}
// Update the indexes
if existing != nil {
eval.CreateIndex = existing.(*structs.Evaluation).CreateIndex
eval.ModifyIndex = index
} else {
eval.CreateIndex = index
eval.ModifyIndex = index
}
// Insert the eval
if err := txn.Insert("evals", eval); err != nil {
return fmt.Errorf("eval insert failed: %v", err)
}
if err := txn.Insert("index", &IndexEntry{"evals", index}); err != nil {
return fmt.Errorf("index update failed: %v", err)
}
return nil
}
// DeleteEval is used to delete an evaluation
func (s *StateStore) DeleteEval(index uint64, evals []string, allocs []string) error {
txn := s.db.Txn(true)
defer txn.Abort()
nodes := make(map[string]struct{})
for _, eval := range evals {
existing, err := txn.First("evals", "id", eval)
if err != nil {
return fmt.Errorf("eval lookup failed: %v", err)
}
if existing == nil {
continue
}
if err := txn.Delete("evals", existing); err != nil {
return fmt.Errorf("eval delete failed: %v", err)
}
}
for _, alloc := range allocs {
existing, err := txn.First("allocs", "id", alloc)
if err != nil {
return fmt.Errorf("alloc lookup failed: %v", err)
}
if existing == nil {
continue
}
nodes[existing.(*structs.Allocation).NodeID] = struct{}{}
if err := txn.Delete("allocs", existing); err != nil {
return fmt.Errorf("alloc delete failed: %v", err)
}
}
// Update the indexes
if err := txn.Insert("index", &IndexEntry{"evals", index}); err != nil {
return fmt.Errorf("index update failed: %v", err)
}
if err := txn.Insert("index", &IndexEntry{"allocs", index}); err != nil {
return fmt.Errorf("index update failed: %v", err)
}
txn.Defer(func() { s.watch.notifyAllocs(nodes) })
txn.Commit()
return nil
}
// EvalByID is used to lookup an eval by its ID
func (s *StateStore) EvalByID(id string) (*structs.Evaluation, error) {
txn := s.db.Txn(false)
existing, err := txn.First("evals", "id", id)
if err != nil {
return nil, fmt.Errorf("eval lookup failed: %v", err)
}
if existing != nil {
return existing.(*structs.Evaluation), nil
}
return nil, nil
}
// EvalsByJob returns all the evaluations by job id
func (s *StateStore) EvalsByJob(jobID string) ([]*structs.Evaluation, error) {
txn := s.db.Txn(false)
// Get an iterator over the node allocations
iter, err := txn.Get("evals", "job", jobID)
if err != nil {
return nil, err
}
var out []*structs.Evaluation
for {
raw := iter.Next()
if raw == nil {
break
}
out = append(out, raw.(*structs.Evaluation))
}
return out, nil
}
// Evals returns an iterator over all the evaluations
func (s *StateStore) Evals() (memdb.ResultIterator, error) {
txn := s.db.Txn(false)
// Walk the entire table
iter, err := txn.Get("evals", "id")
if err != nil {
return nil, err
}
return iter, nil
}
// UpdateAllocFromClient is used to update an allocation based on input
// from a client. While the schedulers are the authority on the allocation for
// most things, some updates are authoritative from the client. Specifically,
// the desired state comes from the schedulers, while the actual state comes
// from clients.
func (s *StateStore) UpdateAllocFromClient(index uint64, alloc *structs.Allocation) error {
txn := s.db.Txn(true)
defer txn.Abort()
// Look for existing alloc
existing, err := txn.First("allocs", "id", alloc.ID)
if err != nil {
return fmt.Errorf("alloc lookup failed: %v", err)
}
// Nothing to do if this does not exist
if existing == nil {
return nil
}
exist := existing.(*structs.Allocation)
// Copy everything from the existing allocation
copyAlloc := new(structs.Allocation)
*copyAlloc = *exist
// Pull in anything the client is the authority on
copyAlloc.ClientStatus = alloc.ClientStatus
copyAlloc.ClientDescription = alloc.ClientDescription
// Update the modify index
copyAlloc.ModifyIndex = index
// Update the allocation
if err := txn.Insert("allocs", copyAlloc); err != nil {
return fmt.Errorf("alloc insert failed: %v", err)
}
// Update the indexes
if err := txn.Insert("index", &IndexEntry{"allocs", index}); err != nil {
return fmt.Errorf("index update failed: %v", err)
}
nodes := map[string]struct{}{alloc.NodeID: struct{}{}}
txn.Defer(func() { s.watch.notifyAllocs(nodes) })
txn.Commit()
return nil
}
// UpsertAllocs is used to evict a set of allocations
// and allocate new ones at the same time.
func (s *StateStore) UpsertAllocs(index uint64, allocs []*structs.Allocation) error {
txn := s.db.Txn(true)
defer txn.Abort()
nodes := make(map[string]struct{})
// Handle the allocations
for _, alloc := range allocs {
existing, err := txn.First("allocs", "id", alloc.ID)
if err != nil {
return fmt.Errorf("alloc lookup failed: %v", err)
}
if existing == nil {
alloc.CreateIndex = index
alloc.ModifyIndex = index
} else {
exist := existing.(*structs.Allocation)
alloc.CreateIndex = exist.CreateIndex
alloc.ModifyIndex = index
alloc.ClientStatus = exist.ClientStatus
alloc.ClientDescription = exist.ClientDescription
}
nodes[alloc.NodeID] = struct{}{}
if err := txn.Insert("allocs", alloc); err != nil {
return fmt.Errorf("alloc insert failed: %v", err)
}
}
// Update the indexes
if err := txn.Insert("index", &IndexEntry{"allocs", index}); err != nil {
return fmt.Errorf("index update failed: %v", err)
}
txn.Defer(func() { s.watch.notifyAllocs(nodes) })
txn.Commit()
return nil
}
// AllocByID is used to lookup an allocation by its ID
func (s *StateStore) AllocByID(id string) (*structs.Allocation, error) {
txn := s.db.Txn(false)
existing, err := txn.First("allocs", "id", id)
if err != nil {
return nil, fmt.Errorf("alloc lookup failed: %v", err)
}
if existing != nil {
return existing.(*structs.Allocation), nil
}
return nil, nil
}
// AllocsByNode returns all the allocations by node
func (s *StateStore) AllocsByNode(node string) ([]*structs.Allocation, error) {
txn := s.db.Txn(false)
// Get an iterator over the node allocations
iter, err := txn.Get("allocs", "node", node)
if err != nil {
return nil, err
}
var out []*structs.Allocation
for {
raw := iter.Next()
if raw == nil {
break
}
out = append(out, raw.(*structs.Allocation))
}
return out, nil
}
// AllocsByJob returns all the allocations by job id
func (s *StateStore) AllocsByJob(jobID string) ([]*structs.Allocation, error) {
txn := s.db.Txn(false)
// Get an iterator over the node allocations
iter, err := txn.Get("allocs", "job", jobID)
if err != nil {
return nil, err
}
var out []*structs.Allocation
for {
raw := iter.Next()
if raw == nil {
break
}
out = append(out, raw.(*structs.Allocation))
}
return out, nil
}
// AllocsByEval returns all the allocations by eval id
func (s *StateStore) AllocsByEval(evalID string) ([]*structs.Allocation, error) {
txn := s.db.Txn(false)
// Get an iterator over the eval allocations
iter, err := txn.Get("allocs", "eval", evalID)
if err != nil {
return nil, err
}
var out []*structs.Allocation
for {
raw := iter.Next()
if raw == nil {
break
}
out = append(out, raw.(*structs.Allocation))
}
return out, nil
}
// Allocs returns an iterator over all the evaluations
func (s *StateStore) Allocs() (memdb.ResultIterator, error) {
txn := s.db.Txn(false)
// Walk the entire table
iter, err := txn.Get("allocs", "id")
if err != nil {
return nil, err
}
return iter, nil
}
// Index finds the matching index value
func (s *StateStore) Index(name string) (uint64, error) {
txn := s.db.Txn(false)
// Lookup the first matching index
out, err := txn.First("index", "id", name)
if err != nil {
return 0, err
}
if out == nil {
return 0, nil
}
return out.(*IndexEntry).Value, nil
}
// Indexes returns an iterator over all the indexes
func (s *StateStore) Indexes() (memdb.ResultIterator, error) {
txn := s.db.Txn(false)
// Walk the entire nodes table
iter, err := txn.Get("index", "id")
if err != nil {
return nil, err
}
return iter, nil
}
// NodeRestore is used to restore a node
func (r *StateRestore) NodeRestore(node *structs.Node) error {
if err := r.txn.Insert("nodes", node); err != nil {
return fmt.Errorf("node insert failed: %v", err)
}
return nil
}
// JobRestore is used to restore a job
func (r *StateRestore) JobRestore(job *structs.Job) error {
if err := r.txn.Insert("jobs", job); err != nil {
return fmt.Errorf("job insert failed: %v", err)
}
return nil
}
// EvalRestore is used to restore an evaluation
func (r *StateRestore) EvalRestore(eval *structs.Evaluation) error {
if err := r.txn.Insert("evals", eval); err != nil {
return fmt.Errorf("eval insert failed: %v", err)
}
return nil
}
// AllocRestore is used to restore an allocation
func (r *StateRestore) AllocRestore(alloc *structs.Allocation) error {
r.allocNodes[alloc.NodeID] = struct{}{}
if err := r.txn.Insert("allocs", alloc); err != nil {
return fmt.Errorf("alloc insert failed: %v", err)
}
return nil
}
// IndexRestore is used to restore an index
func (r *StateRestore) IndexRestore(idx *IndexEntry) error {
if err := r.txn.Insert("index", idx); err != nil {
return fmt.Errorf("index insert failed: %v", err)
}
return nil
}