diff --git a/build/versionize-docs.sh b/build/versionize-docs.sh
index 221ebe6107..601ec07e41 100755
--- a/build/versionize-docs.sh
+++ b/build/versionize-docs.sh
@@ -100,5 +100,6 @@ done
 ${KUBE_ROOT}/hack/update-munge-docs.sh
 ${KUBE_ROOT}/hack/update-generated-swagger-docs.sh
 ${KUBE_ROOT}/hack/update-swagger-spec.sh
+${KUBE_ROOT}/hack/update-openapi-spec.sh
 ${KUBE_ROOT}/hack/update-generated-protobuf.sh
 ./hack/update-api-reference-docs.sh
diff --git a/docs/devel/api_changes.md b/docs/devel/api_changes.md
index afdbaae7be..6488d231d5 100755
--- a/docs/devel/api_changes.md
+++ b/docs/devel/api_changes.md
@@ -590,10 +590,11 @@ out. Put `grep` or `ack` to good use.
 If you added functionality, you should consider documenting it and/or writing
 an example to illustrate your change.
 
-Make sure you update the swagger API spec by running:
+Make sure you update the swagger and OpenAPI spec by running:
 
 ```sh
 hack/update-swagger-spec.sh
+hack/update-openapi-spec.sh
 ```
 
 The API spec changes should be in a commit separate from your other changes.
diff --git a/hack/lib/util.sh b/hack/lib/util.sh
index 46f5f52b7c..0ac651d5cc 100755
--- a/hack/lib/util.sh
+++ b/hack/lib/util.sh
@@ -387,6 +387,59 @@ kube::util::fetch-swagger-spec() {
   curl -w "\n" -fs "${SWAGGER_API_PATH}logs" > "${SWAGGER_ROOT_DIR}/logs.json"
 }
 
+# Takes a group/version and returns the openapi-spec file name.
+# default behavior: extensions/v1beta1 -> v1beta1.extensions
+# special case for v1: v1 -> v1
+kube::util::gv-to-openapi-name() {
+  local group_version="$1"
+  case "${group_version}" in
+    v1)
+      echo "v1"
+      ;;
+    *)
+      echo "${group_version#*/}.${group_version%/*}"
+      ;;
+  esac
+}
+
+
+# Fetches openapi spec from apiserver.
+# Assumed vars:
+# OPENAPI_API_PATH: Base path for openapi on apiserver. normally APIServer root. i.e., http://localhost:8080/
+# OPENAPI_ROOT_DIR: Root dir where we want to to save the fetched spec.
+# VERSIONS: Array of group versions to include in swagger spec.
+kube::util::fetch-openapi-spec() {
+  for ver in ${VERSIONS}; do
+    if [[ " ${KUBE_NONSERVER_GROUP_VERSIONS} " == *" ${ver} "* ]]; then
+      continue
+    fi
+    # fetch the openapi spec for each group version.
+    if [[ ${ver} == "v1" ]]; then
+      SUBPATH="api"
+    else
+      SUBPATH="apis"
+    fi
+    SUBPATH="${SUBPATH}/${ver}"
+    OPENAPI_JSON_NAME="$(kube::util::gv-to-openapi-name ${ver}).json"
+    curl -w "\n" -fs "${OPENAPI_PATH}${SUBPATH}/swagger.json" > "${OPENAPI_ROOT_DIR}/${OPENAPI_JSON_NAME}"
+
+    # fetch the openapi spec for the discovery mechanism at group level.
+    if [[ ${ver} == "v1" ]]; then
+      continue
+    fi
+    SUBPATH="apis/"${ver%/*}
+    OPEAN_JSON_NAME="${ver%/*}.json"
+    curl -w "\n" -fs "${OPENAPI_PATH}${SUBPATH}/swagger.json" > "${OPENAPI_ROOT_DIR}/${OPENAPI_JSON_NAME}"
+  done
+
+  # fetch openapi specs for other discovery mechanism.
+  curl -w "\n" -fs "${OPENAPI_PATH}swagger.json" > "${OPENAPI_ROOT_DIR}/root_swagger.json"
+  curl -w "\n" -fs "${OPENAPI_PATH}version/swagger.json" > "${OPENAPI_ROOT_DIR}/version.json"
+  curl -w "\n" -fs "${OPENAPI_PATH}api/swagger.json" > "${OPENAPI_ROOT_DIR}/api.json"
+  curl -w "\n" -fs "${OPENAPI_PATH}apis/swagger.json" > "${OPENAPI_ROOT_DIR}/apis.json"
+  curl -w "\n" -fs "${OPENAPI_PATH}logs/swagger.json" > "${OPENAPI_ROOT_DIR}/logs.json"
+}
+
 
 # Returns the name of the upstream remote repository name for the local git
 # repo, e.g. "upstream" or "origin".
diff --git a/hack/update-openapi-spec.sh b/hack/update-openapi-spec.sh
new file mode 100755
index 0000000000..b379f16159
--- /dev/null
+++ b/hack/update-openapi-spec.sh
@@ -0,0 +1,75 @@
+#!/bin/bash
+
+# Copyright 2016 The Kubernetes Authors.
+#
+# 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.
+
+# Script to fetch latest openapi spec.
+# Puts the updated spec at api/openapi-spec/
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+KUBE_ROOT=$(dirname "${BASH_SOURCE}")/..
+OPENAPI_ROOT_DIR="${KUBE_ROOT}/api/openapi-spec"
+source "${KUBE_ROOT}/hack/lib/init.sh"
+
+kube::golang::setup_env
+
+make -C "${KUBE_ROOT}" WHAT=cmd/kube-apiserver
+
+function cleanup()
+{
+    [[ -n ${APISERVER_PID-} ]] && kill ${APISERVER_PID} 1>&2 2>/dev/null
+
+    kube::etcd::cleanup
+
+    kube::log::status "Clean up complete"
+}
+
+trap cleanup EXIT SIGINT
+
+kube::golang::setup_env
+
+apiserver=$(kube::util::find-binary "kube-apiserver")
+
+TMP_DIR=$(mktemp -d /tmp/update-openapi-spec.XXXX)
+ETCD_HOST=${ETCD_HOST:-127.0.0.1}
+ETCD_PORT=${ETCD_PORT:-2379}
+API_PORT=${API_PORT:-8050}
+API_HOST=${API_HOST:-127.0.0.1}
+
+kube::etcd::start
+
+# Start kube-apiserver
+kube::log::status "Starting kube-apiserver"
+"${KUBE_OUTPUT_HOSTBIN}/kube-apiserver" \
+  --insecure-bind-address="${API_HOST}" \
+  --bind-address="${API_HOST}" \
+  --insecure-port="${API_PORT}" \
+  --etcd-servers="http://${ETCD_HOST}:${ETCD_PORT}" \
+  --advertise-address="10.10.10.10" \
+  --cert-dir="${TMP_DIR}/certs" \
+  --service-cluster-ip-range="10.0.0.0/24" >/tmp/openapi-api-server.log 2>&1 &
+APISERVER_PID=$!
+
+kube::util::wait_for_url "${API_HOST}:${API_PORT}/healthz" "apiserver: "
+
+kube::log::status "Updating " ${OPENAPI_ROOT_DIR}
+
+OPENAPI_PATH="${API_HOST}:${API_PORT}/" OPENAPI_ROOT_DIR="${OPENAPI_ROOT_DIR}" VERSIONS="${KUBE_AVAILABLE_GROUP_VERSIONS}" KUBE_NONSERVER_GROUP_VERSIONS="${KUBE_NONSERVER_GROUP_VERSIONS}" kube::util::fetch-openapi-spec
+
+kube::log::status "SUCCESS"
+
+# ex: ts=2 sw=2 et filetype=sh
diff --git a/hack/verify-openapi-spec.sh b/hack/verify-openapi-spec.sh
new file mode 100755
index 0000000000..1c45d19add
--- /dev/null
+++ b/hack/verify-openapi-spec.sh
@@ -0,0 +1,51 @@
+#!/bin/bash
+
+# Copyright 2016 The Kubernetes Authors.
+#
+# 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.
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+KUBE_ROOT=$(dirname "${BASH_SOURCE}")/..
+source "${KUBE_ROOT}/hack/lib/init.sh"
+
+kube::golang::setup_env
+
+make -C "${KUBE_ROOT}" WHAT=cmd/kube-apiserver
+
+apiserver=$(kube::util::find-binary "kube-apiserver")
+
+SPECROOT="${KUBE_ROOT}/api/openapi-spec"
+TMP_SPECROOT="${KUBE_ROOT}/_tmp/openapi-spec"
+_tmp="${KUBE_ROOT}/_tmp"
+
+mkdir -p "${_tmp}"
+trap "rm -rf ${_tmp}" EXIT SIGINT
+cp -a "${SPECROOT}" "${TMP_SPECROOT}"
+
+"${KUBE_ROOT}/hack/update-openapi-spec.sh"
+echo "diffing ${SPECROOT} against freshly generated openapi spec"
+ret=0
+diff -Naupr -I 'Auto generated by' "${SPECROOT}" "${TMP_SPECROOT}" || ret=$?
+cp -a ${TMP_SPECROOT} "${KUBE_ROOT}/api"
+if [[ $ret -eq 0 ]]
+then
+  echo "${SPECROOT} up to date."
+else
+  echo "${SPECROOT} is out of date. Please run hack/update-openapi-spec.sh"
+  exit 1
+fi
+
+# ex: ts=2 sw=2 et filetype=sh
diff --git a/hooks/pre-commit b/hooks/pre-commit
index bd4cbe53bc..0f0138b72c 100755
--- a/hooks/pre-commit
+++ b/hooks/pre-commit
@@ -158,6 +158,18 @@ else
 fi
 echo "${reset}"
 
+echo -ne "Checking for openapi spec that need updating... "
+if ! hack/verify-openapi-spec.sh > /dev/null; then
+  echo "${red}ERROR!"
+  echo "Openapi spec needs to be updated."
+  echo "To regenerate the spec, run:"
+  echo "  hack/update-openapi-spec.sh"
+  exit_code=1
+else
+  echo "${green}OK"
+fi
+echo "${reset}"
+
 if [[ "${exit_code}" != 0 ]]; then
   echo "${red}Aborting commit${reset}"
 fi
diff --git a/pkg/genericapiserver/openapi/util.go b/pkg/genericapiserver/openapi/util.go
index b189727c7e..79a8f9d474 100644
--- a/pkg/genericapiserver/openapi/util.go
+++ b/pkg/genericapiserver/openapi/util.go
@@ -42,16 +42,12 @@ func sortParameters(p []spec.Parameter) {
 	sort.Sort(byNameIn{p})
 }
 
-func groupRoutesByPath(routes []restful.Route) (ret map[string][]restful.Route) {
-	ret = make(map[string][]restful.Route)
+func groupRoutesByPath(routes []restful.Route) map[string][]restful.Route {
+	pathToRoutes := make(map[string][]restful.Route)
 	for _, r := range routes {
-		route, exists := ret[r.Path]
-		if !exists {
-			route = make([]restful.Route, 0, 1)
-		}
-		ret[r.Path] = append(route, r)
+		pathToRoutes[r.Path] = append(pathToRoutes[r.Path], r)
 	}
-	return ret
+	return pathToRoutes
 }
 
 func mapKeyFromParam(param *restful.Parameter) interface{} {