Health filter: Only schedule containers on healthy nodes.

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>

manage.go

@@ -75,7 +75,11 @@ func manage(c *cli.Context) {
 	s := scheduler.NewScheduler(
 		cluster,
 		&strategy.BinPackingPlacementStrategy{OvercommitRatio: 0.05},
-		[]filter.Filter{&filter.LabelFilter{}, &filter.PortFilter{}},
+		[]filter.Filter{
+			&filter.HealthFilter{},
+			&filter.LabelFilter{},
+			&filter.PortFilter{},
+		},
 	)
 
 	log.Fatal(api.ListenAndServe(cluster, s, c.String("addr"), c.App.Version))

scheduler/filter/health.go

@@ -0,0 +1,31 @@
+package filter
+
+import (
+	"errors"
+
+	"github.com/docker/swarm/cluster"
+	"github.com/samalba/dockerclient"
+)
+
+var (
+	ErrNoHealthyNodeAvailable = errors.New("No healthy node available in the cluster")
+)
+
+// HealthFilter only schedules containers on healthy nodes.
+type HealthFilter struct {
+}
+
+func (f *HealthFilter) Filter(config *dockerclient.ContainerConfig, nodes []*cluster.Node) ([]*cluster.Node, error) {
+	result := []*cluster.Node{}
+	for _, node := range nodes {
+		if node.IsHealthy() {
+			result = append(result, node)
+		}
+	}
+
+	if len(result) == 0 {
+		return nil, ErrNoHealthyNodeAvailable
+	}
+
+	return result, nil
+}