diff --git a/Dockerfile b/Dockerfile
index 9720e5ed2..7df7816e7 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -11,7 +11,7 @@
 # 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.
-FROM alpine
+FROM alpine:3.7
 MAINTAINER Tom Denham <tom@projectcalico.org>
 
 # Set the minimum Docker API version required for libnetwork.
diff --git a/Dockerfile-ppc64le b/Dockerfile-ppc64le
index b6d120805..e65dd3636 100644
--- a/Dockerfile-ppc64le
+++ b/Dockerfile-ppc64le
@@ -12,7 +12,7 @@
 # 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.
-FROM ppc64le/alpine
+FROM ppc64le/alpine:3.7
 MAINTAINER David Wilder <wilder@us.ibm.com>
 
 # Set the minimum Docker API version required for libnetwork.