Adopt reviewer's advice

templates/tools/dockerfile/python_stretch.include

@@ -7,5 +7,3 @@ FROM debian:stretch
 RUN echo 'deb http://ftp.de.debian.org/debian buster main' >> /etc/apt/sources.list
 RUN echo 'APT::Default-Release "stretch";' | tee -a /etc/apt/apt.conf.d/00local
 <%include file="./run_tests_addons.include"/>
-# Define the default command.
-CMD ["bash"]

templates/tools/dockerfile/test/python_stretch_default_x64/Dockerfile.template

@@ -25,6 +25,9 @@
     cd cpython-3.6.9 && ${'\\'}
     ./configure && ${'\\'}
     make install
+  
+  RUN echo "ff7cdaef4846c89c1ec0d7b709bbd54d v3.6.9.tar.gz" > checksum.md5
+  RUN md5sum -c checksum.md5
 
   RUN apt-get update && apt-get -t buster install -y python3.7 python3-all-dev
   RUN curl https://bootstrap.pypa.io/get-pip.py | python3.7

tools/dockerfile/interoptest/grpc_interop_python/Dockerfile

@@ -63,8 +63,6 @@ RUN echo 'APT::Default-Release "stretch";' | tee -a /etc/apt/apt.conf.d/00local
 
 RUN mkdir /var/local/jenkins
 
-# Define the default command.
-CMD ["bash"]
 
 
 RUN apt-get update && apt-get -t stable install -y python3.7 python3-all-dev

tools/dockerfile/test/python_stretch_2.7_x64/Dockerfile

@@ -63,6 +63,4 @@ RUN echo 'APT::Default-Release "stretch";' | tee -a /etc/apt/apt.conf.d/00local
 
 RUN mkdir /var/local/jenkins
 
-# Define the default command.
-CMD ["bash"]
 

tools/dockerfile/test/python_stretch_3.5_x64/Dockerfile

@@ -63,8 +63,6 @@ RUN echo 'APT::Default-Release "stretch";' | tee -a /etc/apt/apt.conf.d/00local
 
 RUN mkdir /var/local/jenkins
 
-# Define the default command.
-CMD ["bash"]
 
 
 RUN apt-get update && apt-get install -y python3.5 python3-all-dev

tools/dockerfile/test/python_stretch_3.6_x64/Dockerfile

@@ -63,8 +63,6 @@ RUN echo 'APT::Default-Release "stretch";' | tee -a /etc/apt/apt.conf.d/00local
 
 RUN mkdir /var/local/jenkins
 
-# Define the default command.
-CMD ["bash"]
 
 
 RUN apt-get install -y jq zlib1g-dev libssl-dev

tools/dockerfile/test/python_stretch_3.7_x64/Dockerfile

@@ -63,8 +63,6 @@ RUN echo 'APT::Default-Release "stretch";' | tee -a /etc/apt/apt.conf.d/00local
 
 RUN mkdir /var/local/jenkins
 
-# Define the default command.
-CMD ["bash"]
 
 
 RUN apt-get update && apt-get -t buster install -y python3.7 python3-all-dev

tools/dockerfile/test/python_stretch_3.8_x64/Dockerfile

@@ -63,8 +63,6 @@ RUN echo 'APT::Default-Release "stretch";' | tee -a /etc/apt/apt.conf.d/00local
 
 RUN mkdir /var/local/jenkins
 
-# Define the default command.
-CMD ["bash"]
 
 RUN apt-get install -y jq zlib1g-dev libssl-dev
 

tools/dockerfile/test/python_stretch_default_x64/Dockerfile

@@ -63,8 +63,6 @@ RUN echo 'APT::Default-Release "stretch";' | tee -a /etc/apt/apt.conf.d/00local
 
 RUN mkdir /var/local/jenkins
 
-# Define the default command.
-CMD ["bash"]
 
 
 RUN apt-get update && apt-get install -y zlib1g-dev libssl-dev
@@ -77,6 +75,9 @@ RUN cd /tmp && \
   ./configure && \
   make install
 
+RUN echo "ff7cdaef4846c89c1ec0d7b709bbd54d v3.6.9.tar.gz" > checksum.md5
+RUN md5sum -c checksum.md5
+
 RUN apt-get update && apt-get -t buster install -y python3.7 python3-all-dev
 RUN curl https://bootstrap.pypa.io/get-pip.py | python3.7
 

tools/dockerfile/test/sanity/Dockerfile

@@ -63,8 +63,6 @@ RUN echo 'APT::Default-Release "stretch";' | tee -a /etc/apt/apt.conf.d/00local
 
 RUN mkdir /var/local/jenkins
 
-# Define the default command.
-CMD ["bash"]
 
 #=================
 # C++ dependencies