open-nomad/nomad/plan_endpoint_test.go
Tim Gross 4368dcc02f
fix deadlock in plan_apply (#13407)
The plan applier has to get a snapshot with a minimum index for the
plan it's working on in order to ensure consistency. Under heavy raft
loads, we can exceed the timeout. When this happens, we hit a bug
where the plan applier blocks waiting on the `indexCh` forever, and
all schedulers will block in `Plan.Submit`.

Closing the `indexCh` when the `asyncPlanWait` is done with it will
prevent the deadlock without impacting correctness of the previous
snapshot index.

This changeset includes the a PoC failing test that works by injecting
a large timeout into the state store. We need to turn this into a test
we can run normally without breaking the state store before we can
merge this PR.

Increase `snapshotMinIndex` timeout to 10s.
This timeout creates backpressure where any concurrent `Plan.Submit`
RPCs will block waiting for results. This sheds load across all
servers and gives raft some CPU to catch up, because schedulers won't
dequeue more work while waiting. Increase it to 10s based on
observations of large production clusters.
2022-06-23 12:06:27 -04:00

199 lines
4.4 KiB
Go

package nomad
import (
"sync"
"testing"
"time"
msgpackrpc "github.com/hashicorp/net-rpc-msgpackrpc"
"github.com/hashicorp/nomad/ci"
"github.com/hashicorp/nomad/nomad/mock"
"github.com/hashicorp/nomad/nomad/structs"
"github.com/hashicorp/nomad/testutil"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
)
func TestPlanEndpoint_Submit(t *testing.T) {
ci.Parallel(t)
s1, cleanupS1 := TestServer(t, func(c *Config) {
c.NumSchedulers = 0
})
defer cleanupS1()
codec := rpcClient(t, s1)
testutil.WaitForLeader(t, s1.RPC)
// Create the register request
eval1 := mock.Eval()
s1.evalBroker.Enqueue(eval1)
evalOut, token, err := s1.evalBroker.Dequeue([]string{eval1.Type}, time.Second)
if err != nil {
t.Fatalf("err: %v", err)
}
if evalOut != eval1 {
t.Fatalf("Bad eval")
}
// Submit a plan
plan := mock.Plan()
plan.EvalID = eval1.ID
plan.EvalToken = token
plan.Job = mock.Job()
req := &structs.PlanRequest{
Plan: plan,
WriteRequest: structs.WriteRequest{Region: "global"},
}
var resp structs.PlanResponse
if err := msgpackrpc.CallWithCodec(codec, "Plan.Submit", req, &resp); err != nil {
t.Fatalf("err: %v", err)
}
if resp.Result == nil {
t.Fatalf("missing result")
}
}
// TestPlanEndpoint_Submit_Bad asserts that the Plan.Submit endpoint rejects
// bad data with an error instead of panicking.
func TestPlanEndpoint_Submit_Bad(t *testing.T) {
ci.Parallel(t)
s1, cleanupS1 := TestServer(t, func(c *Config) {
c.NumSchedulers = 0
})
defer cleanupS1()
codec := rpcClient(t, s1)
testutil.WaitForLeader(t, s1.RPC)
// Mock a valid eval being dequeued by a worker
eval := mock.Eval()
s1.evalBroker.Enqueue(eval)
evalOut, _, err := s1.evalBroker.Dequeue([]string{eval.Type}, time.Second)
require.NoError(t, err)
require.Equal(t, eval, evalOut)
cases := []struct {
Name string
Plan *structs.Plan
Err string
}{
{
Name: "Nil",
Plan: nil,
Err: "cannot submit nil plan",
},
{
Name: "Empty",
Plan: &structs.Plan{},
Err: "evaluation is not outstanding",
},
{
Name: "BadEvalID",
Plan: &structs.Plan{
EvalID: "1234", // does not exist
},
Err: "evaluation is not outstanding",
},
{
Name: "MissingToken",
Plan: &structs.Plan{
EvalID: eval.ID,
},
Err: "evaluation token does not match",
},
{
Name: "InvalidToken",
Plan: &structs.Plan{
EvalID: eval.ID,
EvalToken: "1234", // invalid
},
Err: "evaluation token does not match",
},
}
for i := range cases {
tc := cases[i]
t.Run(tc.Name, func(t *testing.T) {
req := &structs.PlanRequest{
Plan: tc.Plan,
WriteRequest: structs.WriteRequest{Region: "global"},
}
var resp structs.PlanResponse
err := msgpackrpc.CallWithCodec(codec, "Plan.Submit", req, &resp)
require.EqualError(t, err, tc.Err)
require.Nil(t, resp.Result)
})
}
// Ensure no plans were enqueued
require.Zero(t, s1.planner.planQueue.Stats().Depth)
}
func TestPlanEndpoint_ApplyConcurrent(t *testing.T) {
t.Parallel()
s1, cleanupS1 := TestServer(t, func(c *Config) {
c.NumSchedulers = 0
})
defer cleanupS1()
testutil.WaitForLeader(t, s1.RPC)
plans := []*structs.Plan{}
for i := 0; i < 5; i++ {
// Create a node to place on
node := mock.Node()
store := s1.fsm.State()
require.NoError(t, store.UpsertNode(structs.MsgTypeTestSetup, 100, node))
// Create the eval
eval1 := mock.Eval()
s1.evalBroker.Enqueue(eval1)
require.NoError(t, store.UpsertEvals(
structs.MsgTypeTestSetup, 150, []*structs.Evaluation{eval1}))
evalOut, token, err := s1.evalBroker.Dequeue([]string{eval1.Type}, time.Second)
require.NoError(t, err)
require.Equal(t, eval1, evalOut)
// Submit a plan
plan := mock.Plan()
plan.EvalID = eval1.ID
plan.EvalToken = token
plan.Job = mock.Job()
alloc := mock.Alloc()
alloc.JobID = plan.Job.ID
alloc.Job = plan.Job
plan.NodeAllocation = map[string][]*structs.Allocation{
node.ID: []*structs.Allocation{alloc}}
plans = append(plans, plan)
}
var wg sync.WaitGroup
for _, plan := range plans {
plan := plan
wg.Add(1)
go func() {
req := &structs.PlanRequest{
Plan: plan,
WriteRequest: structs.WriteRequest{Region: "global"},
}
var resp structs.PlanResponse
err := s1.RPC("Plan.Submit", req, &resp)
assert.NoError(t, err)
assert.NotNil(t, resp.Result, "missing result")
wg.Done()
}()
}
wg.Wait()
}