Implement DaemonSet history logic in controller

1. Create controllerrevisions (history) and label pods with template
   hash for both RollingUpdate and OnDelete update strategy
2. Clean up old, non-live history based on revisionHistoryLimit
3. Remove duplicate controllerrevisions (the ones with the same template)
   and relabel their pods
4. Update RBAC to allow DaemonSet controller to manage
   controllerrevisions
5. In DaemonSet controller unit tests, create new pods with hash labels

pkg/controller/controller_utils.go

@@ -17,8 +17,10 @@ limitations under the License.
 package controller
 
 import (
+	"encoding/binary"
 	"encoding/json"
 	"fmt"
+	"hash/fnv"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -29,16 +31,14 @@ import (
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/apimachinery/pkg/util/clock"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/apimachinery/pkg/util/strategicpatch"
 	"k8s.io/apimachinery/pkg/util/wait"
-
-	"k8s.io/apimachinery/pkg/util/clock"
 	"k8s.io/client-go/tools/cache"
 	"k8s.io/client-go/tools/record"
 	"k8s.io/client-go/util/integer"
-
 	"k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/api/v1"
 	v1helper "k8s.io/kubernetes/pkg/api/v1/helper"
@@ -48,6 +48,7 @@ import (
 	extensions "k8s.io/kubernetes/pkg/apis/extensions/v1beta1"
 	"k8s.io/kubernetes/pkg/client/clientset_generated/clientset"
 	clientretry "k8s.io/kubernetes/pkg/client/retry"
+	hashutil "k8s.io/kubernetes/pkg/util/hash"
 
 	"github.com/golang/glog"
 )
@@ -980,3 +981,18 @@ func WaitForCacheSync(controllerName string, stopCh <-chan struct{}, cacheSyncs
 	glog.Infof("Caches are synced for %s controller", controllerName)
 	return true
 }
+
+// ComputeHash returns a hash value calculated from pod template and a collisionCount to avoid hash collision
+func ComputeHash(template *v1.PodTemplateSpec, collisionCount *int64) uint32 {
+	podTemplateSpecHasher := fnv.New32a()
+	hashutil.DeepHashObject(podTemplateSpecHasher, *template)
+
+	// Add collisionCount in the hash if it exists.
+	if collisionCount != nil {
+		collisionCountBytes := make([]byte, 8)
+		binary.LittleEndian.PutUint64(collisionCountBytes, uint64(*collisionCount))
+		podTemplateSpecHasher.Write(collisionCountBytes)
+	}
+
+	return podTemplateSpecHasher.Sum32()
+}