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agent: avoid reverting any check updates that occur while a service is being added or the config is reloaded (#6144)

This commit is contained in:
R.B. Boyer 2019-07-17 14:06:50 -05:00 committed by GitHub
parent 477415b107
commit 4c05f1f519
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 87 additions and 23 deletions
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45
agent/agent.go
View File

@ -457,7 +457,7 @@ func (a *Agent) Start() error {
if err := a.loadProxies(c); err != nil {
return err
}
if err := a.loadChecks(c); err != nil {
if err := a.loadChecks(c, nil); err != nil {
return err
}
if err := a.loadMetadata(c); err != nil {
@ -2109,10 +2109,10 @@ func (a *Agent) addServiceInternal(service *structs.NodeService, chkTypes []*str
a.PauseSync()
defer a.ResumeSync()
// Take a snapshot of the current state of checks (if any), and
// restore them before resuming anti-entropy.
// Take a snapshot of the current state of checks (if any), and when adding
// a check that already existed carry over the state before resuming
// anti-entropy.
snap := a.snapshotCheckState()
defer a.restoreCheckState(snap)
var checks []*structs.HealthCheck
@ -2143,6 +2143,13 @@ func (a *Agent) addServiceInternal(service *structs.NodeService, chkTypes []*str
check.Status = chkType.Status
}
// Restore the fields from the snapshot.
prev, ok := snap[check.CheckID]
if ok {
check.Output = prev.Output
check.Status = prev.Status
}
checks = append(checks, check)
}
@ -3346,10 +3353,17 @@ func (a *Agent) unloadServices() error {
// loadChecks loads check definitions and/or persisted check definitions from
// disk and re-registers them with the local agent.
func (a *Agent) loadChecks(conf *config.RuntimeConfig) error {
func (a *Agent) loadChecks(conf *config.RuntimeConfig, snap map[types.CheckID]*structs.HealthCheck) error {
// Register the checks from config
for _, check := range conf.Checks {
health := check.HealthCheck(conf.NodeName)
// Restore the fields from the snapshot.
if prev, ok := snap[health.CheckID]; ok {
health.Output = prev.Output
health.Status = prev.Status
}
chkType := check.CheckType()
if err := a.addCheckLocked(health, chkType, false, check.Token, ConfigSourceLocal); err != nil {
return fmt.Errorf("Failed to register check '%s': %v %v", check.Name, err, check)
@ -3406,6 +3420,12 @@ func (a *Agent) loadChecks(conf *config.RuntimeConfig) error {
// services into the active pool
p.Check.Status = api.HealthCritical
// Restore the fields from the snapshot.
if prev, ok := snap[p.Check.CheckID]; ok {
p.Check.Output = prev.Output
p.Check.Status = prev.Status
}
if err := a.addCheckLocked(p.Check, p.ChkType, false, p.Token, ConfigSourceLocal); err != nil {
// Purge the check if it is unable to be restored.
a.logger.Printf("[WARN] agent: Failed to restore check %q: %s",
@ -3634,15 +3654,6 @@ func (a *Agent) snapshotCheckState() map[types.CheckID]*structs.HealthCheck {
return a.State.Checks()
}
// restoreCheckState is used to reset the health state based on a snapshot.
// This is done after we finish the reload to avoid any unnecessary flaps
// in health state and potential session invalidations.
func (a *Agent) restoreCheckState(snap map[types.CheckID]*structs.HealthCheck) {
for id, check := range snap {
a.State.UpdateCheck(id, check.Status, check.Output)
}
}
// loadMetadata loads node metadata fields from the agent config and
// updates them on the local agent.
func (a *Agent) loadMetadata(conf *config.RuntimeConfig) error {
@ -3765,9 +3776,9 @@ func (a *Agent) ReloadConfig(newCfg *config.RuntimeConfig) error {
a.stateLock.Lock()
defer a.stateLock.Unlock()
// Snapshot the current state, and restore it afterwards
// Snapshot the current state, and use that to initialize the checks when
// they are recreated.
snap := a.snapshotCheckState()
defer a.restoreCheckState(snap)
// First unload all checks, services, and metadata. This lets us begin the reload
// with a clean slate.
@ -3798,7 +3809,7 @@ func (a *Agent) ReloadConfig(newCfg *config.RuntimeConfig) error {
if err := a.loadProxies(newCfg); err != nil {
return fmt.Errorf("Failed reloading proxies: %s", err)
}
if err := a.loadChecks(newCfg); err != nil {
if err := a.loadChecks(newCfg, snap); err != nil {
return fmt.Errorf("Failed reloading checks: %s", err)
}
if err := a.loadMetadata(newCfg); err != nil {

65
agent/agent_test.go
View File

@ -500,6 +500,62 @@ func TestAgent_AddService(t *testing.T) {
}
}
func TestAgent_AddServices_AliasUpdateCheckNotReverted(t *testing.T) {
t.Parallel()
a := NewTestAgent(t, t.Name(), `
node_name = "node1"
`)
defer a.Shutdown()
// It's tricky to get an UpdateCheck call to be timed properly so it lands
// right in the middle of an addServiceInternal call so we cheat a bit and
// rely upon alias checks to do that work for us. We add enough services
// that probabilistically one of them is going to end up properly in the
// critical section.
//
// The first number I picked here (10) surprisingly failed every time prior
// to PR #6144 solving the underlying problem.
const numServices = 10
services := make([]*structs.ServiceDefinition, numServices)
checkIDs := make([]types.CheckID, numServices)
for i := 0; i < numServices; i++ {
name := fmt.Sprintf("web-%d", i)
services[i] = &structs.ServiceDefinition{
ID: name,
Name: name,
Port: 8080 + i,
Checks: []*structs.CheckType{
&structs.CheckType{
Name: "alias-for-fake-service",
AliasService: "fake",
},
},
}
checkIDs[i] = types.CheckID("service:" + name)
}
// Add all of the services quickly as you might do from config file snippets.
for _, service := range services {
ns := service.NodeService()
chkTypes, err := service.CheckTypes()
require.NoError(t, err)
require.NoError(t, a.AddService(ns, chkTypes, false, service.Token, ConfigSourceLocal))
}
retry.Run(t, func(r *retry.R) {
gotChecks := a.State.Checks()
for id, check := range gotChecks {
require.Equal(r, "passing", check.Status, "check %q is wrong", id)
require.Equal(r, "No checks found.", check.Output, "check %q is wrong", id)
}
})
}
func TestAgent_AddServiceNoExec(t *testing.T) {
t.Parallel()
a := NewTestAgent(t, t.Name(), `
@ -2965,14 +3021,11 @@ func TestAgent_checkStateSnapshot(t *testing.T) {
t.Fatalf("err: %s", err)
}
// Reload the checks
if err := a.loadChecks(a.Config); err != nil {
// Reload the checks and restore the snapshot.
if err := a.loadChecks(a.Config, snap); err != nil {
t.Fatalf("err: %s", err)
}
// Restore the state
a.restoreCheckState(snap)
// Search for the check
out, ok := a.State.Checks()[check1.CheckID]
if !ok {
@ -3010,7 +3063,7 @@ func TestAgent_loadChecks_checkFails(t *testing.T) {
}
// Try loading the checks from the persisted files
if err := a.loadChecks(a.Config); err != nil {
if err := a.loadChecks(a.Config, nil); err != nil {
t.Fatalf("err: %s", err)
}