Minor updates to container build (#213)

* Don't use host UID:GID for "container_build shell"

The UID:GID does not exist in the container. Just use the root account.

* Switch to c++ -> master brach for DPDK building

* Limit parallelism of grpc build

With "make -j", the system may hang due to too many processes

.travis/Dockerfile

@@ -26,10 +26,10 @@ RUN cd /build && \
 	git clone -b $(curl -s -L http://grpc.io/release) https://github.com/grpc/grpc && \
 	cd /build/grpc && \
 	git submodule update --init && \
-	make -j && \
+	make -j4 && \
 	make install && \
 	cd /build/grpc/third_party/protobuf && \
-	make -j && \
+	make -j4 && \
 	make install && \
 	rm -rf /build/grpc
 

.travis/rebuild_image.sh

@@ -4,7 +4,7 @@ set -e
 
 REPOSITORY=${REPOSITORY:-nefelinetworks/bess_build}
 VERSION=${VERSION:-`date +%y%m%d`}
-docker build --build-arg BESS_DPDK_BRANCH=${BESS_DPDK_BRANCH:-c++} -t $REPOSITORY:latest -t $REPOSITORY:$VERSION .
+docker build --build-arg BESS_DPDK_BRANCH=${BESS_DPDK_BRANCH:-master} -t $REPOSITORY:latest -t $REPOSITORY:$VERSION .
 
 echo Build succeeded: $REPOSITORY:$VERSION
 echo Build succeeded: $REPOSITORY:latest

container_build.py

@@ -33,8 +33,8 @@ def run_docker_cmd(cmd):
 
 
 def run_shell():
-    run_cmd('docker run -e CXX -e DEBUG --rm -u %d:%d -it -v %s:%s %s' %
-            (os.getuid(), os.getgid(), BESS_DIR_HOST, BESS_DIR_CONTAINER, IMAGE))
+    run_cmd('docker run -e CXX -e DEBUG --rm -it -v %s:%s %s' %
+            (BESS_DIR_HOST, BESS_DIR_CONTAINER, IMAGE))
 
 
 def build_bess():