From 9c17cceaa335077f0d966ea4701f1aed30801144 Mon Sep 17 00:00:00 2001
From: Armon Dadgar <armon.dadgar@gmail.com>
Date: Tue, 11 Aug 2015 14:04:04 -0700
Subject: [PATCH] scheduler: check node status before evicting

---
 scheduler/scheduler.go     |  3 +++
 scheduler/service_sched.go | 17 +++++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/scheduler/scheduler.go b/scheduler/scheduler.go
index 165e6d79e..82ee4879b 100644
--- a/scheduler/scheduler.go
+++ b/scheduler/scheduler.go
@@ -57,6 +57,9 @@ type State interface {
 
 	// AllocsByJob returns the allocations by JobID
 	AllocsByJob(jobID string) ([]*structs.Allocation, error)
+
+	// GetNodeByID is used to lookup a node by ID
+	GetNodeByID(nodeID string) (*structs.Node, error)
 }
 
 // Planner interface is used to submit a task allocation plan.
diff --git a/scheduler/service_sched.go b/scheduler/service_sched.go
index b64c14220..6e87fd2c1 100644
--- a/scheduler/service_sched.go
+++ b/scheduler/service_sched.go
@@ -52,6 +52,23 @@ func (s *ServiceScheduler) handleJobRegister(eval *structs.Evaluation) error {
 // handleJobDeregister is used to handle a job being deregistered
 func (s *ServiceScheduler) handleJobDeregister(eval *structs.Evaluation) error {
 START:
+	// Lookup the node ID
+	node, err := s.state.GetNodeByID(eval.NodeID)
+	if err != nil {
+		return fmt.Errorf("failed to get node '%s': %v",
+			eval.NodeID, err)
+	}
+
+	// Could be a potential race, and the node is actually fine
+	if node != nil {
+		switch node.Status {
+		case structs.NodeStatusInit, structs.NodeStatusReady, structs.NodeStatusMaint:
+			s.logger.Printf("[DEBUG] sched: (eval %s) not evicting node %s allocs, status %s",
+				eval.ID, eval.NodeID, node.Status)
+			return nil
+		}
+	}
+
 	// Lookup the allocations by JobID
 	allocs, err := s.state.AllocsByJob(eval.JobID)
 	if err != nil {