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Make locking simpler

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add test for node existence cache behavior
This commit is contained in:
Daniel Smith 2014-12-22 14:11:41 -08:00
parent dc5383dcf8
commit 6916235513
2 changed files with 115 additions and 47 deletions
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90
pkg/master/pod_cache.go
View File

@ -80,28 +80,35 @@ func (p *PodCache) GetPodStatus(namespace, name string) (*api.PodStatus, error)
return &value, nil
}
// lock must *not* be held
func (p *PodCache) nodeExists(name string) bool {
func (p *PodCache) nodeExistsInCache(name string) (exists, cacheHit bool) {
p.lock.Lock()
defer p.lock.Unlock()
exists, cacheHit := p.currentNodes[objKey{"", name}]
exists, cacheHit = p.currentNodes[objKey{"", name}]
return exists, cacheHit
}
// lock must *not* be held
func (p *PodCache) nodeExists(name string) bool {
exists, cacheHit := p.nodeExistsInCache(name)
if cacheHit {
return exists
}
// Don't block everyone while looking up this minion.
// Because this may require an RPC to our storage (e.g. etcd).
func() {
p.lock.Unlock()
defer p.lock.Lock()
_, err := p.nodes.Get(name)
exists = true
if err != nil {
exists = false
if !errors.IsNotFound(err) {
glog.Errorf("Unexpected error type verifying minion existence: %+v", err)
}
// TODO: suppose there's N concurrent requests for node "foo"; in that case
// it might be useful to block all of them and only look up "foo" once.
// (This code will make up to N lookups.) One way of doing that would be to
// have a pool of M mutexes and require that before looking up "foo" you must
// lock mutex hash("foo") % M.
_, err := p.nodes.Get(name)
exists = true
if err != nil {
exists = false
if !errors.IsNotFound(err) {
glog.Errorf("Unexpected error type verifying minion existence: %+v", err)
}
}()
}
p.lock.Lock()
defer p.lock.Unlock()
p.currentNodes[objKey{"", name}] = exists
return exists
}
@ -109,23 +116,32 @@ func (p *PodCache) nodeExists(name string) bool {
// TODO: once Host gets moved to spec, this can take a podSpec + metadata instead of an
// entire pod?
func (p *PodCache) updatePodStatus(pod *api.Pod) error {
newStatus, err := p.computePodStatus(pod)
p.lock.Lock()
defer p.lock.Unlock()
// Map accesses must be locked.
p.podStatus[objKey{pod.Namespace, pod.Name}] = newStatus
return err
}
// computePodStatus always returns a new status, even if it also returns a non-nil error.
// TODO: once Host gets moved to spec, this can take a podSpec + metadata instead of an
// entire pod?
func (p *PodCache) computePodStatus(pod *api.Pod) (api.PodStatus, error) {
newStatus := pod.Status
if pod.Status.Host == "" {
p.lock.Lock()
defer p.lock.Unlock()
// Not assigned.
newStatus.Phase = api.PodPending
p.podStatus[objKey{pod.Namespace, pod.Name}] = newStatus
return nil
return newStatus, nil
}
if !p.nodeExists(pod.Status.Host) {
p.lock.Lock()
defer p.lock.Unlock()
// Assigned to non-existing node.
newStatus.Phase = api.PodFailed
p.podStatus[objKey{pod.Namespace, pod.Name}] = newStatus
return nil
return newStatus, nil
}
info, err := p.containerInfo.GetPodInfo(pod.Status.Host, pod.Namespace, pod.Name)
@ -142,27 +158,33 @@ func (p *PodCache) updatePodStatus(pod *api.Pod) error {
}
}
}
return newStatus, err
}
func (p *PodCache) resetNodeExistenceCache() {
p.lock.Lock()
defer p.lock.Unlock()
p.podStatus[objKey{pod.Namespace, pod.Name}] = newStatus
return err
p.currentNodes = map[objKey]bool{}
}
// UpdateAllContainers updates information about all containers.
// Callers should let one call to UpdateAllContainers finish before
// calling again, or risk having new info getting clobbered by delayed
// old info.
func (p *PodCache) UpdateAllContainers() {
func() {
// Reset which nodes we think exist
p.lock.Lock()
defer p.lock.Unlock()
p.currentNodes = map[objKey]bool{}
}()
p.resetNodeExistenceCache()
ctx := api.NewContext()
pods, err := p.pods.ListPods(ctx, labels.Everything())
if err != nil {
glog.Errorf("Error synchronizing container list: %v", err)
glog.Errorf("Error getting pod list: %v", err)
return
}
// TODO: this algorithm is 1 goroutine & RPC per pod. With a little work,
// it should be possible to make it 1 per *node*, which will be important
// at very large scales. (To be clear, the goroutines shouldn't matter--
// it's the RPCs that need to be minimized.)
var wg sync.WaitGroup
for i := range pods.Items {
pod := &pods.Items[i]
@ -171,7 +193,7 @@ func (p *PodCache) UpdateAllContainers() {
defer wg.Done()
err := p.updatePodStatus(pod)
if err != nil && err != client.ErrPodInfoNotAvailable {
glog.Errorf("Error synchronizing container: %v", err)
glog.Errorf("Error getting info for pod %v/%v: %v", pod.Namespace, pod.Name, err)
}
}()
}

72
pkg/master/pod_cache_test.go
View File

@ -18,6 +18,7 @@ package master
import (
"reflect"
"sync"
"testing"
"time"
@ -27,19 +28,48 @@ import (
"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
)
type FakePodInfoGetter struct {
type podInfoCall struct {
host string
id string
namespace string
data api.PodContainerInfo
err error
name string
}
func (f *FakePodInfoGetter) GetPodInfo(host, namespace, id string) (api.PodContainerInfo, error) {
f.host = host
f.id = id
f.namespace = namespace
return f.data, f.err
type podInfoResponse struct {
useCount int
data api.PodContainerInfo
err error
}
type podInfoCalls map[podInfoCall]*podInfoResponse
type FakePodInfoGetter struct {
calls podInfoCalls
lock sync.Mutex
// default data/error to return, or you can add
// responses to specific calls-- that will take precedence.
data api.PodContainerInfo
err error
}
func (f *FakePodInfoGetter) GetPodInfo(host, namespace, name string) (api.PodContainerInfo, error) {
f.lock.Lock()
defer f.lock.Unlock()
if f.calls == nil {
f.calls = podInfoCalls{}
}
key := podInfoCall{host, namespace, name}
call, ok := f.calls[key]
if !ok {
f.calls[key] = &podInfoResponse{
0, f.data, f.err,
}
call = f.calls[key]
}
call.useCount++
return call.data, call.err
}
func TestPodCacheGetDifferentNamespace(t *testing.T) {
@ -171,6 +201,7 @@ func makeNode(name string) *api.Node {
func TestPodUpdateAllContainers(t *testing.T) {
pod := makePod(api.NamespaceDefault, "foo", "machine", "bar")
pod2 := makePod(api.NamespaceDefault, "baz", "machine", "qux")
config := podCacheTestConfig{
ipFunc: func(host string) string {
if host == "machine" {
@ -180,15 +211,22 @@ func TestPodUpdateAllContainers(t *testing.T) {
},
kubeletContainerInfo: api.PodInfo{"bar": api.ContainerStatus{}},
nodes: []api.Node{*makeNode("machine")},
pods: []api.Pod{*pod},
pods: []api.Pod{*pod, *pod2},
}
cache := config.Construct()
cache.UpdateAllContainers()
fake := config.fakePodInfo
if fake.host != "machine" || fake.id != "foo" || fake.namespace != api.NamespaceDefault {
t.Errorf("Unexpected access: %+v", fake)
call1 := config.fakePodInfo.calls[podInfoCall{"machine", api.NamespaceDefault, "foo"}]
call2 := config.fakePodInfo.calls[podInfoCall{"machine", api.NamespaceDefault, "baz"}]
if call1 == nil || call1.useCount != 1 {
t.Errorf("Expected 1 call for 'foo': %+v", config.fakePodInfo.calls)
}
if call2 == nil || call2.useCount != 1 {
t.Errorf("Expected 1 call for 'baz': %+v", config.fakePodInfo.calls)
}
if len(config.fakePodInfo.calls) != 2 {
t.Errorf("Expected 2 calls: %+v", config.fakePodInfo.calls)
}
status, err := cache.GetPodStatus(api.NamespaceDefault, "foo")
@ -201,6 +239,14 @@ func TestPodUpdateAllContainers(t *testing.T) {
if e, a := "1.2.3.5", status.HostIP; e != a {
t.Errorf("Unexpected mismatch. Expected: %+v, Got: %+v", e, a)
}
if e, a := 1, len(config.fakeNodes.Actions); e != a {
t.Errorf("Expected: %v, Got: %v; %+v", e, a, config.fakeNodes.Actions)
} else {
if e, a := "get-minion", config.fakeNodes.Actions[0].Action; e != a {
t.Errorf("Expected: %v, Got: %v; %+v", e, a, config.fakeNodes.Actions)
}
}
}
func TestFillPodStatusNoHost(t *testing.T) {