Emit events based on eligibility

nomad/fsm.go

@@ -384,7 +384,7 @@ func (n *nomadFSM) applyNodeEligibilityUpdate(buf []byte, index uint64) interfac
 		return err
 	}
 
-	if err := n.state.UpdateNodeEligibility(index, req.NodeID, req.Eligibility); err != nil {
+	if err := n.state.UpdateNodeEligibility(index, req.NodeID, req.Eligibility, req.NodeEvent); err != nil {
 		n.logger.Printf("[ERR] nomad.fsm: UpdateNodeEligibility failed: %v", err)
 		return err
 	}

nomad/fsm_test.go

@@ -451,10 +451,17 @@ func TestFSM_UpdateNodeEligibility(t *testing.T) {
 	resp := fsm.Apply(makeLog(buf))
 	require.Nil(resp)
 
+	event := &structs.NodeEvent{
+		Message:   "Node marked as ineligible",
+		Subsystem: structs.NodeEventSubsystemCluster,
+		Timestamp: time.Now(),
+	}
+
 	// Set the eligibility
 	req2 := structs.NodeUpdateEligibilityRequest{
 		NodeID:      node.ID,
 		Eligibility: structs.NodeSchedulingIneligible,
+		NodeEvent:   event,
 	}
 	buf, err = structs.Encode(structs.NodeUpdateEligibilityRequestType, req2)
 	require.Nil(err)
@@ -466,6 +473,8 @@ func TestFSM_UpdateNodeEligibility(t *testing.T) {
 	node, err = fsm.State().NodeByID(nil, req.Node.ID)
 	require.Nil(err)
 	require.Equal(node.SchedulingEligibility, structs.NodeSchedulingIneligible)
+	require.Len(node.Events, 2)
+	require.Equal(event.Message, node.Events[1].Message)
 
 	// Update the drain
 	strategy := &structs.DrainStrategy{

nomad/node_endpoint.go

@@ -32,6 +32,14 @@ const (
 	NodeDrainEventDrainSet      = "Node drain strategy set"
 	NodeDrainEventDrainDisabled = "Node drain disabled"
 	NodeDrainEventDrainUpdated  = "Node drain stategy updated"
+
+	// NodeEligibilityEventEligible is used when the nodes eligiblity is marked
+	// eligible
+	NodeEligibilityEventEligible = "Node marked as eligible for scheduling"
+
+	// NodeEligibilityEventIneligible is used when the nodes eligiblity is marked
+	// ineligible
+	NodeEligibilityEventIneligible = "Node marked as ineligible for scheduling"
 )
 
 // Node endpoint is used for client interactions
@@ -532,6 +540,9 @@ func (n *Node) UpdateEligibility(args *structs.NodeUpdateEligibilityRequest,
 	if args.NodeID == "" {
 		return fmt.Errorf("missing node ID for setting scheduling eligibility")
 	}
+	if args.NodeEvent != nil {
+		return fmt.Errorf("node event may not be set")
+	}
 
 	// Check that only allowed types are set
 	switch args.Eligibility {
@@ -563,6 +574,16 @@ func (n *Node) UpdateEligibility(args *structs.NodeUpdateEligibilityRequest,
 		return fmt.Errorf("invalid scheduling eligibility %q", args.Eligibility)
 	}
 
+	// Construct the node event
+	args.NodeEvent = structs.NewNodeEvent().SetSubsystem(structs.NodeEventSubsystemCluster)
+	if node.SchedulingEligibility == args.Eligibility {
+		return nil // Nothing to do
+	} else if args.Eligibility == structs.NodeSchedulingEligible {
+		args.NodeEvent.SetMessage(NodeEligibilityEventEligible)
+	} else {
+		args.NodeEvent.SetMessage(NodeEligibilityEventIneligible)
+	}
+
 	// Commit this update via Raft
 	outErr, index, err := n.srv.raftApply(structs.NodeUpdateEligibilityRequestType, args)
 	if err != nil {

nomad/node_endpoint_test.go

@@ -1095,6 +1095,8 @@ func TestClientEndpoint_UpdateEligibility(t *testing.T) {
 	out, err := state.NodeByID(nil, node.ID)
 	require.Nil(err)
 	require.Equal(out.SchedulingEligibility, structs.NodeSchedulingIneligible)
+	require.Len(out.Events, 2)
+	require.Equal(NodeEligibilityEventIneligible, out.Events[1].Message)
 
 	// Register a system job
 	job := mock.SystemJob()
@@ -1107,6 +1109,11 @@ func TestClientEndpoint_UpdateEligibility(t *testing.T) {
 	require.NotZero(resp3.Index)
 	require.NotZero(resp3.EvalCreateIndex)
 	require.Len(resp3.EvalIDs, 1)
+
+	out, err = state.NodeByID(nil, node.ID)
+	require.Nil(err)
+	require.Len(out.Events, 3)
+	require.Equal(NodeEligibilityEventEligible, out.Events[2].Message)
 }
 
 func TestClientEndpoint_UpdateEligibility_ACL(t *testing.T) {

nomad/state/state_store.go

@@ -688,7 +688,7 @@ func (s *StateStore) updateNodeDrainImpl(txn *memdb.Txn, index uint64, nodeID st
 }
 
 // UpdateNodeEligibility is used to update the scheduling eligibility of a node
-func (s *StateStore) UpdateNodeEligibility(index uint64, nodeID string, eligibility string) error {
+func (s *StateStore) UpdateNodeEligibility(index uint64, nodeID string, eligibility string, event *structs.NodeEvent) error {
 
 	txn := s.db.Txn(true)
 	defer txn.Abort()
@@ -706,6 +706,11 @@ func (s *StateStore) UpdateNodeEligibility(index uint64, nodeID string, eligibil
 	existingNode := existing.(*structs.Node)
 	copyNode := existingNode.Copy()
 
+	// Add the event if given
+	if event != nil {
+		appendNodeEvents(index, copyNode, []*structs.NodeEvent{event})
+	}
+
 	// Check if this is a valid action
 	if copyNode.DrainStrategy != nil && eligibility == structs.NodeSchedulingEligible {
 		return fmt.Errorf("can not set node's scheduling eligibility to eligible while it is draining")

nomad/state/state_store_test.go

@@ -952,13 +952,20 @@ func TestStateStore_UpdateNodeEligibility(t *testing.T) {
 		t.Fatalf("bad: %v", err)
 	}
 
-	require.Nil(state.UpdateNodeEligibility(1001, node.ID, expectedEligibility))
+	event := &structs.NodeEvent{
+		Message:   "Node marked as ineligible",
+		Subsystem: structs.NodeEventSubsystemCluster,
+		Timestamp: time.Now(),
+	}
+	require.Nil(state.UpdateNodeEligibility(1001, node.ID, expectedEligibility, event))
 	require.True(watchFired(ws))
 
 	ws = memdb.NewWatchSet()
 	out, err := state.NodeByID(ws, node.ID)
 	require.Nil(err)
 	require.Equal(out.SchedulingEligibility, expectedEligibility)
+	require.Len(out.Events, 2)
+	require.Equal(out.Events[1], event)
 	require.EqualValues(1001, out.ModifyIndex)
 
 	index, err := state.Index("nodes")
@@ -975,7 +982,7 @@ func TestStateStore_UpdateNodeEligibility(t *testing.T) {
 	require.Nil(state.UpdateNodeDrain(1002, node.ID, expectedDrain, false, nil))
 
 	// Try to set the node to eligible
-	err = state.UpdateNodeEligibility(1003, node.ID, structs.NodeSchedulingEligible)
+	err = state.UpdateNodeEligibility(1003, node.ID, structs.NodeSchedulingEligible, nil)
 	require.NotNil(err)
 	require.Contains(err.Error(), "while it is draining")
 }

nomad/structs/structs.go

@@ -376,6 +376,10 @@ type DrainUpdate struct {
 type NodeUpdateEligibilityRequest struct {
 	NodeID      string
 	Eligibility string
+
+	// NodeEvent is the event added to the node
+	NodeEvent *NodeEvent
+
 	WriteRequest
 }