diff --git a/java/compatibility_tests/v2.5.0/test.sh b/java/compatibility_tests/v2.5.0/test.sh
index 2ea5b9302..eea832850 100755
--- a/java/compatibility_tests/v2.5.0/test.sh
+++ b/java/compatibility_tests/v2.5.0/test.sh
@@ -5,6 +5,9 @@ set -ex
 # Change to the script's directory.
 cd $(dirname $0)
 
+MAVEN_LOCAL_REPOSITORY=/var/maven_local_repository
+MVN="mvn --batch-mode -e -X -Dhttps.protocols=TLSv1.2 -Dmaven.repo.local=$MAVEN_LOCAL_REPOSITORY"
+
 # Version of the tests (i.e., the version of protobuf from where we extracted
 # these tests).
 TEST_VERSION=`grep "^  <version>.*</version>" pom.xml | sed "s|  <version>\(.*\)</version>|\1|"`
@@ -59,7 +62,7 @@ echo "Running compatibility tests between $VERSION_NUMBER and $OLD_VERSION"
 # Build and install protobuf-java-$VERSION_NUMBER.jar
 [ -f ../../core/target/protobuf-java-$VERSION_NUMBER.jar ] || {
   pushd ../..
-  mvn install -Dmaven.test.skip=true
+  $MVN install -Dmaven.test.skip=true
   popd
 }
 
@@ -81,7 +84,7 @@ chmod +x protoc
 # Test A.1:
 #   protos: use new version
 #   more_protos: use old version
-mvn clean test \
+$MVN clean test \
   -Dprotobuf.test.source.path=$(pwd)/protobuf \
   -Dprotoc.path=$(pwd)/protoc \
   -Dprotos.protoc.path=$(pwd)/../../../src/protoc \
@@ -90,7 +93,7 @@ mvn clean test \
 # Test A.2:
 #   protos: use old version
 #   more_protos: use new version
-mvn clean test \
+$MVN clean test \
   -Dprotobuf.test.source.path=$(pwd)/protobuf \
   -Dprotoc.path=$(pwd)/protoc \
   -Dmore_protos.protoc.path=$(pwd)/../../../src/protoc \
@@ -103,12 +106,12 @@ mvn clean test \
 # make it easier to run binary compatibility test (where we will need to run
 # the jar files directly).
 cd deps
-mvn assembly:single
+$MVN assembly:single
 cd ..
 cp -f deps/target/compatibility-test-deps-${TEST_VERSION}-jar-with-dependencies.jar deps.jar
 
 # Build the old version of all 3 artifacts.
-mvn clean install -Dmaven.test.skip=true -Dprotoc.path=$(pwd)/protoc -Dprotobuf.version=$OLD_VERSION
+$MVN clean install -Dmaven.test.skip=true -Dprotoc.path=$(pwd)/protoc -Dprotobuf.version=$OLD_VERSION
 cp -f protos/target/compatibility-protos-${TEST_VERSION}.jar protos.jar
 cp -f more_protos/target/compatibility-more-protos-${TEST_VERSION}.jar more_protos.jar
 cp -f tests/target/compatibility-tests-${TEST_VERSION}.jar tests.jar
@@ -125,7 +128,7 @@ cd ..
 
 # Test B.2: update protos.jar only.
 cd protos
-mvn clean package -Dmaven.test.skip=true -Dprotoc.path=$(pwd)/../../../../src/protoc -Dprotobuf.version=$VERSION_NUMBER
+$MVN clean package -Dmaven.test.skip=true -Dprotoc.path=$(pwd)/../../../../src/protoc -Dprotobuf.version=$VERSION_NUMBER
 cd ..
 cd protobuf
 java -cp ../../../core/target/protobuf-java-$VERSION_NUMBER.jar:../protos/target/compatibility-protos-${TEST_VERSION}.jar:../more_protos.jar:../tests.jar:../deps.jar org.junit.runner.JUnitCore $TESTS
@@ -133,7 +136,7 @@ cd ..
 
 # Test B.3: update more_protos.jar only.
 cd more_protos
-mvn clean package -Dmaven.test.skip=true -Dprotoc.path=$(pwd)/../../../../src/protoc -Dprotobuf.version=$VERSION_NUMBER
+$MVN clean package -Dmaven.test.skip=true -Dprotoc.path=$(pwd)/../../../../src/protoc -Dprotobuf.version=$VERSION_NUMBER
 cd ..
 cd protobuf
 java -cp ../../../core/target/protobuf-java-$VERSION_NUMBER.jar:../protos.jar:../more_protos/target/compatibility-more-protos-${TEST_VERSION}.jar:../tests.jar:../deps.jar org.junit.runner.JUnitCore $TESTS
diff --git a/kokoro/linux/csharp/build.sh b/kokoro/linux/csharp/build.sh
index de178b844..27cb549da 100755
--- a/kokoro/linux/csharp/build.sh
+++ b/kokoro/linux/csharp/build.sh
@@ -1,11 +1,17 @@
 #!/bin/bash
 #
-# Build file to set up and run tests
+# This is the top-level script we give to Kokoro as the entry point for
+# running the "pull request" project:
+#
+# This script selects a specific Dockerfile (for building a Docker image) and
+# a script to run inside that image.  Then we delegate to the general
+# build_and_run_docker.sh script.
 
 # Change to repo root
 cd $(dirname $0)/../../..
 
-# Prepare worker environment to run tests
-source kokoro/linux/prepare_build_linux_rc
-
-./tests.sh csharp
+export DOCKERFILE_DIR=kokoro/linux/64-bit
+export DOCKER_RUN_SCRIPT=kokoro/linux/pull_request_in_docker.sh
+export OUTPUT_DIR=testoutput
+export TEST_SET="csharp"
+./kokoro/linux/build_and_run_docker.sh
diff --git a/kokoro/linux/java_compatibility/build.sh b/kokoro/linux/java_compatibility/build.sh
index b1ef27963..de88454fc 100755
--- a/kokoro/linux/java_compatibility/build.sh
+++ b/kokoro/linux/java_compatibility/build.sh
@@ -1,11 +1,17 @@
 #!/bin/bash
 #
-# Build file to set up and run tests
+# This is the top-level script we give to Kokoro as the entry point for
+# running the "pull request" project:
+#
+# This script selects a specific Dockerfile (for building a Docker image) and
+# a script to run inside that image.  Then we delegate to the general
+# build_and_run_docker.sh script.
 
 # Change to repo root
 cd $(dirname $0)/../../..
 
-# Prepare worker environment to run tests
-source kokoro/linux/prepare_build_linux_rc
-
-./tests.sh java_compatibility
+export DOCKERFILE_DIR=kokoro/linux/64-bit
+export DOCKER_RUN_SCRIPT=kokoro/linux/pull_request_in_docker.sh
+export OUTPUT_DIR=testoutput
+export TEST_SET="java_compatibility"
+./kokoro/linux/build_and_run_docker.sh
diff --git a/kokoro/linux/prepare_build_linux_rc b/kokoro/linux/prepare_build_linux_rc
deleted file mode 100644
index d9b3bec3a..000000000
--- a/kokoro/linux/prepare_build_linux_rc
+++ /dev/null
@@ -1,13 +0,0 @@
-#!/bin/bash
-
-# Source this rc script to prepare the environment for Linux builds
-
-# Set up dotnet
-sudo sh -c 'echo "deb [arch=amd64] https://packages.microsoft.com/repos/microsoft-ubuntu-trusty-prod trusty main" > /etc/apt/sources.list.d/dotnetdev.list'
-sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys EB3E94ADBE1229CF
-sudo apt-get update
-# We use the .NET Core SDK 2.x to build...
-sudo apt-get install -y dotnet-sdk-2.1.3
-# But we also need the 1.x framework to test against, as we
-# target netstandard1.x
-sudo apt-get install -y dotnet-sharedframework-microsoft.netcore.app-1.0.5
diff --git a/kokoro/linux/python_compatibility/build.sh b/kokoro/linux/python_compatibility/build.sh
index 041e65ffb..1ba35394d 100755
--- a/kokoro/linux/python_compatibility/build.sh
+++ b/kokoro/linux/python_compatibility/build.sh
@@ -1,11 +1,17 @@
 #!/bin/bash
 #
-# Build file to set up and run tests
+# This is the top-level script we give to Kokoro as the entry point for
+# running the "pull request" project:
+#
+# This script selects a specific Dockerfile (for building a Docker image) and
+# a script to run inside that image.  Then we delegate to the general
+# build_and_run_docker.sh script.
 
 # Change to repo root
 cd $(dirname $0)/../../..
 
-# Prepare worker environment to run tests
-source kokoro/linux/prepare_build_linux_rc
-
-./tests.sh python_compatibility
+export DOCKERFILE_DIR=kokoro/linux/64-bit
+export DOCKER_RUN_SCRIPT=kokoro/linux/pull_request_in_docker.sh
+export OUTPUT_DIR=testoutput
+export TEST_SET="python_compatibility"
+./kokoro/linux/build_and_run_docker.sh