diff --git a/tools/jenkins/build_interop_image.sh b/tools/jenkins/build_interop_image.sh
index 166efbd9e2f0123048ac22910fc356bdf205fc37..5dfa24251344878d3dd857da4207ef6c267bfd71 100755
--- a/tools/jenkins/build_interop_image.sh
+++ b/tools/jenkins/build_interop_image.sh
@@ -33,6 +33,13 @@
 
 set -x
 
+# Params:
+#  INTEROP_IMAGE - name of tag of the final interop image
+#  BASE_NAME - base name used to locate the base Dockerfile and build script
+#  TTY_FLAG - optional -t flag to make docker allocate tty
+#  BUILD_INTEROP_DOCKER_EXTRA_ARGS - optional args to be passed to the
+#    docker run command
+
 cd `dirname $0`/../..
 GRPC_ROOT=`pwd`
 MOUNT_ARGS="-v $GRPC_ROOT:/var/local/jenkins/grpc:ro"
@@ -55,11 +62,6 @@ fi
 
 mkdir -p /tmp/ccache
 
-# Params:
-#  INTEROP_IMAGE - name of tag of the final interop image
-#  BASE_NAME - base name used to locate the base Dockerfile and build script
-#  TTY_FLAG - optional -t flag to make docker allocate tty.
-
 # Mount service account dir if available.
 # If service_directory does not contain the service account JSON file,
 # some of the tests will fail.
@@ -84,6 +86,7 @@ CONTAINER_NAME="build_${BASE_NAME}_$(uuidgen)"
   -e CCACHE_DIR=/tmp/ccache \
   -i $TTY_FLAG \
   $MOUNT_ARGS \
+  $BUILD_INTEROP_DOCKER_EXTRA_ARGS \
   -v /tmp/ccache:/tmp/ccache \
   --name=$CONTAINER_NAME \
   $BASE_IMAGE \
diff --git a/tools/jenkins/grpc_interop_php/Dockerfile b/tools/jenkins/grpc_interop_php/Dockerfile
index 0edc3c174d4561777758c9aa44926f268a1e922f..09da71369170a33d61d37e20d61c7e6e8acb4525 100644
--- a/tools/jenkins/grpc_interop_php/Dockerfile
+++ b/tools/jenkins/grpc_interop_php/Dockerfile
@@ -87,12 +87,6 @@ RUN /bin/bash -l -c "gem install bundler --no-ri --no-rdoc"
 
 # Install dependencies
 
-RUN /bin/bash -l -c "echo 'deb http://packages.dotdeb.org wheezy-php55 all' \
-    >> /etc/apt/sources.list.d/dotdeb.list"
-RUN /bin/bash -l -c "echo 'deb-src http://packages.dotdeb.org wheezy-php55 all' \
-    >> /etc/apt/sources.list.d/dotdeb.list"
-RUN wget http://www.dotdeb.org/dotdeb.gpg -O- | apt-key add -
-
 RUN apt-get update && apt-get install -y \
     git php5 php5-dev phpunit unzip
 
@@ -102,8 +96,6 @@ RUN apt-get update && apt-get install -y \
 # rake: a ruby version of make used to build the PHP Protobuf extension
 RUN /bin/bash -l -c "rvm all do gem install ronn rake"
 
-ENV DEBIAN_FRONTEND noniteractive
-
 # Install composer
 RUN curl -sS https://getcomposer.org/installer | php
 RUN mv composer.phar /usr/local/bin/composer