open-nomad/client/allochealth/tracker_test.go
Mahmood Ali 07a30580ac health: fail health if any task is pending
Fixes a bug where an allocation is considered healthy if some of the
tasks are being restarted and as such, their checks aren't tracked by
consul agent client.

Here, we fix the immediate case by ensuring that an alloc is healthy
only if tasks are running and the registered checks at the time are
healthy.

Previously, health tracker tracked task "health" independently from
checks and leads to problems when a task restarts.  Consider the
following series of events:

1. all tasks start running -> `tracker.tasksHealthy` is true
2. one task has unhealthy checks and get restarted
3. remaining checks are healthy -> `tracker.checksHealthy` is true
4. propagate health status now that `tracker.tasksHealthy` and
`tracker.checksHealthy`.

This change ensures that we accurately use the latest status of tasks
and checks regardless of their status changes.

Also, ensures that we only consider check health after tasks are
considered healthy, otherwise we risk trusting incomplete checks.

This approach accomodates task dependencies well.  Service jobs can have
prestart short-lived tasks that will terminate before main process runs.
These dead tasks that complete successfully will not negate health
status.
2020-03-22 11:13:41 -04:00

230 lines
5.7 KiB
Go

package allochealth
import (
"context"
"fmt"
"sync/atomic"
"testing"
"time"
consulapi "github.com/hashicorp/consul/api"
"github.com/hashicorp/nomad/client/consul"
cstructs "github.com/hashicorp/nomad/client/structs"
agentconsul "github.com/hashicorp/nomad/command/agent/consul"
"github.com/hashicorp/nomad/helper/testlog"
"github.com/hashicorp/nomad/nomad/mock"
"github.com/hashicorp/nomad/nomad/structs"
"github.com/hashicorp/nomad/testutil"
"github.com/stretchr/testify/require"
)
func TestTracker_Checks_Healthy(t *testing.T) {
t.Parallel()
alloc := mock.Alloc()
alloc.Job.TaskGroups[0].Migrate.MinHealthyTime = 1 // let's speed things up
task := alloc.Job.TaskGroups[0].Tasks[0]
// Synthesize running alloc and tasks
alloc.ClientStatus = structs.AllocClientStatusRunning
alloc.TaskStates = map[string]*structs.TaskState{
task.Name: {
State: structs.TaskStateRunning,
StartedAt: time.Now(),
},
}
// Make Consul response
check := &consulapi.AgentCheck{
Name: task.Services[0].Checks[0].Name,
Status: consulapi.HealthPassing,
}
taskRegs := map[string]*agentconsul.ServiceRegistrations{
task.Name: {
Services: map[string]*agentconsul.ServiceRegistration{
task.Services[0].Name: {
Service: &consulapi.AgentService{
ID: "foo",
Service: task.Services[0].Name,
},
Checks: []*consulapi.AgentCheck{check},
},
},
},
}
logger := testlog.HCLogger(t)
b := cstructs.NewAllocBroadcaster(logger)
defer b.Close()
// Don't reply on the first call
var called uint64
consul := consul.NewMockConsulServiceClient(t, logger)
consul.AllocRegistrationsFn = func(string) (*agentconsul.AllocRegistration, error) {
if atomic.AddUint64(&called, 1) == 1 {
return nil, nil
}
reg := &agentconsul.AllocRegistration{
Tasks: taskRegs,
}
return reg, nil
}
ctx, cancelFn := context.WithCancel(context.Background())
defer cancelFn()
checkInterval := 10 * time.Millisecond
tracker := NewTracker(ctx, logger, alloc, b.Listen(), consul,
time.Millisecond, true)
tracker.checkLookupInterval = checkInterval
tracker.Start()
select {
case <-time.After(4 * checkInterval):
require.Fail(t, "timed out while waiting for health")
case h := <-tracker.HealthyCh():
require.True(t, h)
}
}
func TestTracker_Checks_Unhealthy(t *testing.T) {
t.Parallel()
alloc := mock.Alloc()
alloc.Job.TaskGroups[0].Migrate.MinHealthyTime = 1 // let's speed things up
task := alloc.Job.TaskGroups[0].Tasks[0]
newCheck := task.Services[0].Checks[0].Copy()
newCheck.Name = "failing-check"
task.Services[0].Checks = append(task.Services[0].Checks, newCheck)
// Synthesize running alloc and tasks
alloc.ClientStatus = structs.AllocClientStatusRunning
alloc.TaskStates = map[string]*structs.TaskState{
task.Name: {
State: structs.TaskStateRunning,
StartedAt: time.Now(),
},
}
// Make Consul response
checkHealthy := &consulapi.AgentCheck{
Name: task.Services[0].Checks[0].Name,
Status: consulapi.HealthPassing,
}
checksUnhealthy := &consulapi.AgentCheck{
Name: task.Services[0].Checks[1].Name,
Status: consulapi.HealthCritical,
}
taskRegs := map[string]*agentconsul.ServiceRegistrations{
task.Name: {
Services: map[string]*agentconsul.ServiceRegistration{
task.Services[0].Name: {
Service: &consulapi.AgentService{
ID: "foo",
Service: task.Services[0].Name,
},
Checks: []*consulapi.AgentCheck{checkHealthy, checksUnhealthy},
},
},
},
}
logger := testlog.HCLogger(t)
b := cstructs.NewAllocBroadcaster(logger)
defer b.Close()
// Don't reply on the first call
var called uint64
consul := consul.NewMockConsulServiceClient(t, logger)
consul.AllocRegistrationsFn = func(string) (*agentconsul.AllocRegistration, error) {
if atomic.AddUint64(&called, 1) == 1 {
return nil, nil
}
reg := &agentconsul.AllocRegistration{
Tasks: taskRegs,
}
return reg, nil
}
ctx, cancelFn := context.WithCancel(context.Background())
defer cancelFn()
checkInterval := 10 * time.Millisecond
tracker := NewTracker(ctx, logger, alloc, b.Listen(), consul,
time.Millisecond, true)
tracker.checkLookupInterval = checkInterval
tracker.Start()
testutil.WaitForResult(func() (bool, error) {
lookup := atomic.LoadUint64(&called)
return lookup < 4, fmt.Errorf("wait to get more task registration lookups: %v", lookup)
}, func(err error) {
require.NoError(t, err)
})
tracker.l.Lock()
require.False(t, tracker.checksHealthy)
tracker.l.Unlock()
select {
case v := <-tracker.HealthyCh():
require.Failf(t, "expected no health value", " got %v", v)
default:
// good
}
}
func TestTracker_Healthy_IfBothTasksAndConsulChecksAreHealthy(t *testing.T) {
t.Parallel()
alloc := mock.Alloc()
logger := testlog.HCLogger(t)
ctx, cancelFn := context.WithCancel(context.Background())
defer cancelFn()
tracker := NewTracker(ctx, logger, alloc, nil, nil,
time.Millisecond, true)
assertNoHealth := func() {
require.NoError(t, tracker.ctx.Err())
select {
case v := <-tracker.HealthyCh():
require.Failf(t, "unexpected healthy event", "got %v", v)
default:
}
}
// first set task health without checks
tracker.setTaskHealth(true, false)
assertNoHealth()
// now fail task health again before checks are successful
tracker.setTaskHealth(false, false)
assertNoHealth()
// now pass health checks - do not propagate health yet
tracker.setCheckHealth(true)
assertNoHealth()
// set tasks to healthy - don't propagate health yet, wait for the next check
tracker.setTaskHealth(true, false)
assertNoHealth()
// set checks to true, now propagate health status
tracker.setCheckHealth(true)
require.Error(t, tracker.ctx.Err())
select {
case v := <-tracker.HealthyCh():
require.True(t, v)
default:
require.Fail(t, "expected a health status")
}
}