diff --git a/tools/interop_matrix/testcases/python__master b/tools/interop_matrix/testcases/python__master
index 71ba75e5d1f..467e41ff82f 100755
--- a/tools/interop_matrix/testcases/python__master
+++ b/tools/interop_matrix/testcases/python__master
@@ -1,20 +1,20 @@
 #!/bin/bash
 echo "Testing ${docker_image:=grpc_interop_python:797ca293-94e8-48d4-92e9-a4d52fcfcca9}"
-docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test.sandbox.googleapis.com --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=large_unary\""
-docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test.sandbox.googleapis.com --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=empty_unary\""
-docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test.sandbox.googleapis.com --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=ping_pong\""
-docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test.sandbox.googleapis.com --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=empty_stream\""
-docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test.sandbox.googleapis.com --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=client_streaming\""
-docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test.sandbox.googleapis.com --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=server_streaming\""
-docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test.sandbox.googleapis.com --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=cancel_after_begin\""
-docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test.sandbox.googleapis.com --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=cancel_after_first_response\""
-docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test.sandbox.googleapis.com --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=timeout_on_sleeping_server\""
-docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test4.sandbox.googleapis.com --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=large_unary\""
-docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test4.sandbox.googleapis.com --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=empty_unary\""
-docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test4.sandbox.googleapis.com --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=ping_pong\""
-docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test4.sandbox.googleapis.com --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=empty_stream\""
-docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test4.sandbox.googleapis.com --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=client_streaming\""
-docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test4.sandbox.googleapis.com --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=server_streaming\""
-docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test4.sandbox.googleapis.com --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=cancel_after_begin\""
-docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test4.sandbox.googleapis.com --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=cancel_after_first_response\""
-docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test4.sandbox.googleapis.com --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=timeout_on_sleeping_server\""
+docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27_native/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test.sandbox.googleapis.com --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=large_unary\""
+docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27_native/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test.sandbox.googleapis.com --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=empty_unary\""
+docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27_native/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test.sandbox.googleapis.com --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=ping_pong\""
+docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27_native/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test.sandbox.googleapis.com --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=empty_stream\""
+docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27_native/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test.sandbox.googleapis.com --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=client_streaming\""
+docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27_native/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test.sandbox.googleapis.com --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=server_streaming\""
+docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27_native/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test.sandbox.googleapis.com --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=cancel_after_begin\""
+docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27_native/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test.sandbox.googleapis.com --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=cancel_after_first_response\""
+docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27_native/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test.sandbox.googleapis.com --server_host_override=grpc-test.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=timeout_on_sleeping_server\""
+docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27_native/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test4.sandbox.googleapis.com --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=large_unary\""
+docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27_native/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test4.sandbox.googleapis.com --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=empty_unary\""
+docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27_native/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test4.sandbox.googleapis.com --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=ping_pong\""
+docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27_native/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test4.sandbox.googleapis.com --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=empty_stream\""
+docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27_native/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test4.sandbox.googleapis.com --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=client_streaming\""
+docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27_native/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test4.sandbox.googleapis.com --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=server_streaming\""
+docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27_native/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test4.sandbox.googleapis.com --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=cancel_after_begin\""
+docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27_native/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test4.sandbox.googleapis.com --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=cancel_after_first_response\""
+docker run -i --rm=true -e PYTHONPATH=/var/local/git/grpc/src/python/gens -e LD_LIBRARY_PATH=/var/local/git/grpc/libs/opt -w /var/local/git/grpc --net=host $docker_image bash -c "py27_native/bin/python src/python/grpcio_tests/setup.py run_interop --client --args=\"--server_host=grpc-test4.sandbox.googleapis.com --server_host_override=grpc-test4.sandbox.googleapis.com --server_port=443 --use_tls=true --test_case=timeout_on_sleeping_server\""