Implement replica set controller.

pkg/controller/replicaset/doc.go

+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package replicaset contains logic for watching and synchronizing
+// ReplicaSets.
+package replicaset

pkg/controller/replicaset/replica_set_utils.go

+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// If you make changes to this file, you should also make the corresponding change in ReplicationController.
+
+package replicaset
+
+import (
+	"github.com/golang/glog"
+	"k8s.io/kubernetes/pkg/apis/extensions"
+	client "k8s.io/kubernetes/pkg/client/unversioned"
+)
+
+// updateReplicaCount attempts to update the Status.Replicas of the given ReplicaSet, with a single GET/PUT retry.
+func updateReplicaCount(rsClient client.ReplicaSetInterface, rs extensions.ReplicaSet, numReplicas int) (updateErr error) {
+	// This is the steady state. It happens when the ReplicaSet doesn't have any expectations, since
+	// we do a periodic relist every 30s. If the generations differ but the replicas are
+	// the same, a caller might've resized to the same replica count.
+	if rs.Status.Replicas == numReplicas &&
+		rs.Generation == rs.Status.ObservedGeneration {
+		return nil
+	}
+	// Save the generation number we acted on, otherwise we might wrongfully indicate
+	// that we've seen a spec update when we retry.
+	// TODO: This can clobber an update if we allow multiple agents to write to the
+	// same status.
+	generation := rs.Generation
+
+	var getErr error
+	for i, rs := 0, &rs; ; i++ {
+		glog.V(4).Infof("Updating replica count for ReplicaSet: %v, %d->%d (need %d), sequence No: %v->%v",
+			rs.Name, rs.Status.Replicas, numReplicas, rs.Spec.Replicas, rs.Status.ObservedGeneration, generation)
+
+		rs.Status = extensions.ReplicaSetStatus{Replicas: numReplicas, ObservedGeneration: generation}
+		_, updateErr = rsClient.UpdateStatus(rs)
+		if updateErr == nil || i >= statusUpdateRetries {
+			return updateErr
+		}
+		// Update the ReplicaSet with the latest resource version for the next poll
+		if rs, getErr = rsClient.Get(rs.Name); getErr != nil {
+			// If the GET fails we can't trust status.Replicas anymore. This error
+			// is bound to be more interesting than the update failure.
+			return getErr
+		}
+	}
+}
+
+// overlappingReplicaSets sorts a list of ReplicaSets by creation timestamp, using their names as a tie breaker.
+type overlappingReplicaSets []extensions.ReplicaSet
+
+func (o overlappingReplicaSets) Len() int      { return len(o) }
+func (o overlappingReplicaSets) Swap(i, j int) { o[i], o[j] = o[j], o[i] }
+
+func (o overlappingReplicaSets) Less(i, j int) bool {
+	if o[i].CreationTimestamp.Equal(o[j].CreationTimestamp) {
+		return o[i].Name < o[j].Name
+	}
+	return o[i].CreationTimestamp.Before(o[j].CreationTimestamp)
+}

pkg/controller/replication/replication_controller.go

@@ -14,6 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+// If you make changes to this file, you should also make the corresponding change in ReplicaSet.
+
 package replication
 
 import (

pkg/controller/replication/replication_controller_test.go

@@ -14,6 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+// If you make changes to this file, you should also make the corresponding change in ReplicaSet.
+
 package replication
 
 import (

pkg/controller/replication/replication_controller_utils.go

@@ -14,6 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+// If you make changes to this file, you should also make the corresponding change in ReplicaSet.
+
 package replication
 
 import (