diff --git a/tools/internal_ci/linux/grpc_xds_k8s.sh b/tools/internal_ci/linux/grpc_xds_k8s.sh
index ba9e2cddbed..71bcdb70122 100755
--- a/tools/internal_ci/linux/grpc_xds_k8s.sh
+++ b/tools/internal_ci/linux/grpc_xds_k8s.sh
@@ -13,13 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-set -ex -o igncr || set -ex
+set -eo pipefail
 
 # Constants
 readonly GITHUB_REPOSITORY_NAME="grpc"
-# GKE Cluster
-readonly GKE_CLUSTER_NAME="interop-test-psm-sec-v2-us-central1-a"
-readonly GKE_CLUSTER_ZONE="us-central1-a"
+readonly TEST_DRIVER_INSTALL_SCRIPT_URL="https://raw.githubusercontent.com/${TEST_DRIVER_REPO_OWNER:-grpc}/grpc/${TEST_DRIVER_BRANCH:-master}/tools/internal_ci/linux/grpc_xds_k8s_install_test_driver.sh"
 ## xDS test server/client Docker images
 readonly SERVER_IMAGE_NAME="gcr.io/grpc-testing/xds-interop/cpp-server"
 readonly CLIENT_IMAGE_NAME="gcr.io/grpc-testing/xds-interop/cpp-client"
@@ -136,8 +134,13 @@ run_test() {
 main() {
   local script_dir
   script_dir="$(dirname "$0")"
-  # shellcheck source=tools/internal_ci/linux/grpc_xds_k8s_install_test_driver.sh
-  source "${script_dir}/grpc_xds_k8s_install_test_driver.sh"
+
+  # Source the test driver from the master branch.
+  echo "Sourcing test driver install script from: ${TEST_DRIVER_INSTALL_SCRIPT_URL}"
+  source /dev/stdin <<< "$(curl -s "${TEST_DRIVER_INSTALL_SCRIPT_URL}")"
+
+  activate_gke_cluster GKE_CLUSTER_PSM_SECURITY
+
   set -x
   if [[ -n "${KOKORO_ARTIFACTS_DIR}" ]]; then
     kokoro_setup_test_driver "${GITHUB_REPOSITORY_NAME}"
diff --git a/tools/internal_ci/linux/grpc_xds_k8s_install_test_driver.sh b/tools/internal_ci/linux/grpc_xds_k8s_install_test_driver.sh
index ba3beaa1d94..bb333c3f4e5 100644
--- a/tools/internal_ci/linux/grpc_xds_k8s_install_test_driver.sh
+++ b/tools/internal_ci/linux/grpc_xds_k8s_install_test_driver.sh
@@ -24,6 +24,72 @@ readonly TEST_DRIVER_BRANCH="${TEST_DRIVER_BRANCH:-master}"
 readonly TEST_DRIVER_PATH="tools/run_tests/xds_k8s_test_driver"
 readonly TEST_DRIVER_PROTOS_PATH="src/proto/grpc/testing"
 
+# GKE cluster identifiers.
+readonly GKE_CLUSTER_PSM_LB="psm-lb"
+readonly GKE_CLUSTER_PSM_SECURITY="psm-security"
+readonly GKE_CLUSTER_PSM_BASIC="psm-basic"
+
+#######################################
+# Determines the cluster name and zone based on the given cluster identifier.
+# Globals:
+#   GKE_CLUSTER_NAME: Set to reflect the cluster name to use
+#   GKE_CLUSTER_ZONE: Set to reflect the cluster zone to use.
+# Arguments:
+#   The cluster identifier
+# Outputs:
+#   Writes the output to stdout, stderr
+#######################################
+activate_gke_cluster() {
+  case $1 in
+    GKE_CLUSTER_PSM_LB)
+      GKE_CLUSTER_NAME="interop-test-psm-lb-v1-us-central1-a"
+      GKE_CLUSTER_ZONE="us-central1-a"
+      ;;
+    GKE_CLUSTER_PSM_SECURITY)
+      GKE_CLUSTER_NAME="interop-test-psm-sec-v2-us-central1-a"
+      GKE_CLUSTER_ZONE="us-central1-a"
+      ;;
+    GKE_CLUSTER_PSM_BASIC)
+      GKE_CLUSTER_NAME="interop-test-psm-basic"
+      GKE_CLUSTER_ZONE="us-central1-c"
+      ;;      
+    *)
+      echo "Unknown GKE cluster: ${1}"
+      exit 1
+      ;;
+  esac
+  echo "Activated GKE cluster: GKE_CLUSTER_NAME=${GKE_CLUSTER_NAME} GKE_CLUSTER_ZONE=${GKE_CLUSTER_ZONE}"
+}
+
+#######################################
+# Determines the secondary cluster name and zone based on the given cluster
+# identifier.
+# Globals:
+#   GKE_CLUSTER_NAME: Set to reflect the cluster name to use
+#   GKE_CLUSTER_ZONE: Set to reflect the cluster zone to use.
+# Arguments:
+#   The cluster identifier
+# Outputs:
+#   Writes the output to stdout, stderr
+#######################################
+activate_secondary_gke_cluster() {
+  case $1 in
+    GKE_CLUSTER_PSM_LB)
+      SECONDARY_GKE_CLUSTER_NAME="interop-test-psm-lb-v1-us-west1-b"
+      SECONDARY_GKE_CLUSTER_ZONE="us-west1-b"
+      ;;
+    GKE_CLUSTER_PSM_SECURITY)
+      SECONDARY_GKE_CLUSTER_NAME="interop-test-psm-sec-v2-us-west1-b"
+      SECONDARY_GKE_CLUSTER_ZONE="us-west1-b"
+      ;;
+    *)
+      echo "Unknown secondary GKE cluster: ${1}"
+      exit 1
+      ;;
+  esac
+  echo "Activated secondary GKE cluster: GKE_CLUSTER_NAME=${GKE_CLUSTER_NAME} GKE_CLUSTER_ZONE=${GKE_CLUSTER_ZONE}"
+}
+
 #######################################
 # Run command end report its exit code. Doesn't exit on non-zero exit code.
 # Globals:
@@ -342,13 +408,12 @@ kokoro_setup_test_driver() {
 #   TEST_DRIVER_REPO_DIR: Unless provided, populated with a temporary dir with
 #                         the path to the test driver repo
 #   SRC_DIR: Populated with absolute path to the source repo
-#   TEST_DRIVER_FULL_DIR: Populated with the path to the test driver source code
+#   KUBE_CONTEXT: Populated with name of kubectl context with GKE cluster access
 #   TEST_DRIVER_FLAGFILE: Populated with relative path to test driver flagfile
 #   TEST_XML_OUTPUT_DIR: Populated with the path to test xUnit XML report
 #   GIT_ORIGIN_URL: Populated with the origin URL of git repo used for the build
 #   GIT_COMMIT: Populated with the SHA-1 of git commit being built
-#   GIT_COMMIT_SHORT: Populated with the short SHA-1 of git commit being built
-#   KUBE_CONTEXT: Populated with name of kubectl context with GKE cluster access
+#   GIT_COMMIT_SHORT: Populated with the short SHA-1 of git commit being built  
 #   SECONDARY_KUBE_CONTEXT: Populated with name of kubectl context with secondary GKE cluster access, if any
 # Arguments:
 #   The path to the folder containing the build script
@@ -358,12 +423,14 @@ kokoro_setup_test_driver() {
 local_setup_test_driver() {
   local script_dir="${1:?Usage: local_setup_test_driver SCRIPT_DIR}"
   readonly SRC_DIR="$(git -C "${script_dir}" rev-parse --show-toplevel)"
-  parse_src_repo_git_info SRC_DIR
+  parse_src_repo_git_info "${SRC_DIR}"
   readonly KUBE_CONTEXT="${KUBE_CONTEXT:-$(kubectl config current-context)}"
   readonly SECONDARY_KUBE_CONTEXT="${SECONDARY_KUBE_CONTEXT}"
+
   local test_driver_repo_dir
   test_driver_repo_dir="${TEST_DRIVER_REPO_DIR:-$(mktemp -d)/${TEST_DRIVER_REPO_NAME}}"
   test_driver_install "${test_driver_repo_dir}"
+
   # shellcheck disable=SC2034  # Used in the main script
   readonly TEST_DRIVER_FLAGFILE="config/local-dev.cfg"
   # Test out
diff --git a/tools/internal_ci/linux/grpc_xds_k8s_lb.sh b/tools/internal_ci/linux/grpc_xds_k8s_lb.sh
index a3595e384a1..606a2541f83 100755
--- a/tools/internal_ci/linux/grpc_xds_k8s_lb.sh
+++ b/tools/internal_ci/linux/grpc_xds_k8s_lb.sh
@@ -17,11 +17,7 @@ set -eo pipefail
 
 # Constants
 readonly GITHUB_REPOSITORY_NAME="grpc"
-# GKE Cluster
-readonly GKE_CLUSTER_NAME="interop-test-psm-lb-v1-us-central1-a"
-readonly GKE_CLUSTER_ZONE="us-central1-a"
-readonly SECONDARY_GKE_CLUSTER_NAME="interop-test-psm-lb-v1-us-west1-b"
-readonly SECONDARY_GKE_CLUSTER_ZONE="us-west1-b"
+readonly TEST_DRIVER_INSTALL_SCRIPT_URL="https://raw.githubusercontent.com/${TEST_DRIVER_REPO_OWNER:-grpc}/grpc/${TEST_DRIVER_BRANCH:-master}/tools/internal_ci/linux/grpc_xds_k8s_install_test_driver.sh"
 ## xDS test client Docker images
 readonly SERVER_IMAGE_NAME="gcr.io/grpc-testing/xds-interop/cpp-server"
 readonly CLIENT_IMAGE_NAME="gcr.io/grpc-testing/xds-interop/cpp-client"
@@ -139,8 +135,14 @@ run_alpha_test() {
 main() {
   local script_dir
   script_dir="$(dirname "$0")"
-  # shellcheck source=tools/internal_ci/linux/grpc_xds_k8s_install_test_driver.sh
-  source "${script_dir}/grpc_xds_k8s_install_test_driver.sh"
+
+  # Source the test driver from the master branch.
+  echo "Sourcing test driver install script from: ${TEST_DRIVER_INSTALL_SCRIPT_URL}"
+  source /dev/stdin <<< "$(curl -s "${TEST_DRIVER_INSTALL_SCRIPT_URL}")"
+
+  activate_gke_cluster GKE_CLUSTER_PSM_LB
+  activate_secondary_gke_cluster GKE_CLUSTER_PSM_LB
+
   set -x
   if [[ -n "${KOKORO_ARTIFACTS_DIR}" ]]; then
     kokoro_setup_test_driver "${GITHUB_REPOSITORY_NAME}"
@@ -148,6 +150,7 @@ main() {
     local_setup_test_driver "${script_dir}"
   fi
   build_docker_images_if_needed
+
   # Run tests
   cd "${TEST_DRIVER_FULL_DIR}"
   local failed_tests=0
diff --git a/tools/internal_ci/linux/grpc_xds_k8s_lb_python.sh b/tools/internal_ci/linux/grpc_xds_k8s_lb_python.sh
index 72766b12d04..7cf7318e72b 100755
--- a/tools/internal_ci/linux/grpc_xds_k8s_lb_python.sh
+++ b/tools/internal_ci/linux/grpc_xds_k8s_lb_python.sh
@@ -17,11 +17,7 @@ set -eo pipefail
 
 # Constants
 readonly GITHUB_REPOSITORY_NAME="grpc"
-# GKE Cluster
-readonly GKE_CLUSTER_NAME="interop-test-psm-sec-v2-us-central1-a"
-readonly GKE_CLUSTER_ZONE="us-central1-a"
-readonly SECONDARY_GKE_CLUSTER_NAME="interop-test-psm-sec-v2-us-west1-b"
-readonly SECONDARY_GKE_CLUSTER_ZONE="us-west1-b"
+readonly TEST_DRIVER_INSTALL_SCRIPT_URL="https://raw.githubusercontent.com/${TEST_DRIVER_REPO_OWNER:-grpc}/grpc/${TEST_DRIVER_BRANCH:-master}/tools/internal_ci/linux/grpc_xds_k8s_install_test_driver.sh"
 ## xDS test client Docker images
 readonly SERVER_IMAGE_NAME="gcr.io/grpc-testing/xds-interop/cpp-server:13171a8b293837517c0446ec0e149e9d10ea3d10"
 readonly CLIENT_IMAGE_NAME="gcr.io/grpc-testing/xds-interop/python-client"
@@ -133,8 +129,14 @@ run_test() {
 main() {
   local script_dir
   script_dir="$(dirname "$0")"
-  # shellcheck source=tools/internal_ci/linux/grpc_xds_k8s_install_test_driver.sh
-  source "${script_dir}/grpc_xds_k8s_install_test_driver.sh"
+  
+  # Source the test driver from the master branch.
+  echo "Sourcing test driver install script from: ${TEST_DRIVER_INSTALL_SCRIPT_URL}"
+  source /dev/stdin <<< "$(curl -s "${TEST_DRIVER_INSTALL_SCRIPT_URL}")"
+
+  activate_gke_cluster GKE_CLUSTER_PSM_SECURITY
+  activate_secondary_gke_cluster GKE_CLUSTER_PSM_SECURITY
+
   set -x
   if [[ -n "${KOKORO_ARTIFACTS_DIR}" ]]; then
     kokoro_setup_test_driver "${GITHUB_REPOSITORY_NAME}"
@@ -142,6 +144,7 @@ main() {
     local_setup_test_driver "${script_dir}"
   fi
   build_docker_images_if_needed
+
   # Run tests
   cd "${TEST_DRIVER_FULL_DIR}"
   local failed_tests=0
diff --git a/tools/internal_ci/linux/grpc_xds_k8s_python.sh b/tools/internal_ci/linux/grpc_xds_k8s_python.sh
index 605102751be..7911596bff0 100755
--- a/tools/internal_ci/linux/grpc_xds_k8s_python.sh
+++ b/tools/internal_ci/linux/grpc_xds_k8s_python.sh
@@ -13,13 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-set -ex -o igncr || set -ex
+set -eo pipefail
 
 # Constants
 readonly GITHUB_REPOSITORY_NAME="grpc"
-# GKE Cluster
-readonly GKE_CLUSTER_NAME="interop-test-psm-sec-v2-us-central1-a"
-readonly GKE_CLUSTER_ZONE="us-central1-a"
+readonly TEST_DRIVER_INSTALL_SCRIPT_URL="https://raw.githubusercontent.com/${TEST_DRIVER_REPO_OWNER:-grpc}/grpc/${TEST_DRIVER_BRANCH:-master}/tools/internal_ci/linux/grpc_xds_k8s_install_test_driver.sh"
 ## xDS test server/client Docker images
 readonly SERVER_IMAGE_NAME="gcr.io/grpc-testing/xds-interop/python-server"
 readonly CLIENT_IMAGE_NAME="gcr.io/grpc-testing/xds-interop/python-client"
@@ -151,8 +149,13 @@ run_test() {
 main() {
   local script_dir
   script_dir="$(dirname "$0")"
-  # shellcheck source=tools/internal_ci/linux/grpc_xds_k8s_install_test_driver.sh
-  source "${script_dir}/grpc_xds_k8s_install_test_driver.sh"
+
+  # Source the test driver from the master branch.
+  echo "Sourcing test driver install script from: ${TEST_DRIVER_INSTALL_SCRIPT_URL}"
+  source /dev/stdin <<< "$(curl -s "${TEST_DRIVER_INSTALL_SCRIPT_URL}")"
+
+  activate_gke_cluster GKE_CLUSTER_PSM_SECURITY
+
   set -x
   if [[ -n "${KOKORO_ARTIFACTS_DIR}" ]]; then
     kokoro_setup_test_driver "${GITHUB_REPOSITORY_NAME}"
diff --git a/tools/internal_ci/linux/grpc_xds_k8s_xlang.sh b/tools/internal_ci/linux/grpc_xds_k8s_xlang.sh
index c7564dfdd19..a424818d1ac 100755
--- a/tools/internal_ci/linux/grpc_xds_k8s_xlang.sh
+++ b/tools/internal_ci/linux/grpc_xds_k8s_xlang.sh
@@ -17,10 +17,7 @@ set -eo pipefail
 
 # Constants
 readonly GITHUB_REPOSITORY_NAME="grpc"
-# GKE Cluster
-readonly GKE_CLUSTER_NAME="interop-test-psm-sec-v2-us-central1-a"
-readonly GKE_CLUSTER_ZONE="us-central1-a"
-
+readonly TEST_DRIVER_INSTALL_SCRIPT_URL="https://raw.githubusercontent.com/${TEST_DRIVER_REPO_OWNER:-grpc}/grpc/${TEST_DRIVER_BRANCH:-master}/tools/internal_ci/linux/grpc_xds_k8s_install_test_driver.sh"
 ## xDS test server/client Docker images
 readonly IMAGE_REPO="gcr.io/grpc-testing/xds-interop"
 readonly SERVER_LANG="cpp go java"
@@ -85,8 +82,14 @@ run_test() {
 main() {
   local script_dir
   script_dir="$(dirname "$0")"
-  # shellcheck source=tools/internal_ci/linux/grpc_xds_k8s_install_test_driver.sh
-  source "${script_dir}/grpc_xds_k8s_install_test_driver.sh"
+
+  # Clone the test driver from the master branch using an external script.
+  # shellcheck source=tools/internal_ci/linux/grpc_xds_k8s_clone_driver_repo.sh
+  source "${script_dir}/grpc_xds_k8s_clone_driver_repo.sh"
+  clone_test_driver
+
+  activate_gke_cluster GKE_CLUSTER_PSM_SECURITY
+
   set -x
   if [[ -n "${KOKORO_ARTIFACTS_DIR}" ]]; then
     kokoro_setup_test_driver "${GITHUB_REPOSITORY_NAME}"
diff --git a/tools/internal_ci/linux/grpc_xds_url_map.sh b/tools/internal_ci/linux/grpc_xds_url_map.sh
index f823f6c5433..696ef97d0d0 100755
--- a/tools/internal_ci/linux/grpc_xds_url_map.sh
+++ b/tools/internal_ci/linux/grpc_xds_url_map.sh
@@ -13,13 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-set -ex -o igncr || set -ex
+set -eo pipefail
 
 # Constants
 readonly GITHUB_REPOSITORY_NAME="grpc"
-# GKE Cluster
-readonly GKE_CLUSTER_NAME="interop-test-psm-basic"
-readonly GKE_CLUSTER_ZONE="us-central1-c"
+readonly TEST_DRIVER_INSTALL_SCRIPT_URL="https://raw.githubusercontent.com/${TEST_DRIVER_REPO_OWNER:-grpc}/grpc/${TEST_DRIVER_BRANCH:-master}/tools/internal_ci/linux/grpc_xds_k8s_install_test_driver.sh"
 ## xDS test client Docker images
 readonly CLIENT_IMAGE_NAME="gcr.io/grpc-testing/xds-interop/cpp-client"
 readonly FORCE_IMAGE_BUILD="${FORCE_IMAGE_BUILD:-0}"
@@ -120,8 +118,13 @@ run_test() {
 main() {
   local script_dir
   script_dir="$(dirname "$0")"
-  # shellcheck source=tools/internal_ci/linux/grpc_xds_k8s_install_test_driver.sh
-  source "${script_dir}/grpc_xds_k8s_install_test_driver.sh"
+
+  # Source the test driver from the master branch.
+  echo "Sourcing test driver install script from: ${TEST_DRIVER_INSTALL_SCRIPT_URL}"
+  source /dev/stdin <<< "$(curl -s "${TEST_DRIVER_INSTALL_SCRIPT_URL}")"
+
+  activate_gke_cluster GKE_CLUSTER_PSM_BASIC
+
   set -x
   if [[ -n "${KOKORO_ARTIFACTS_DIR}" ]]; then
     kokoro_setup_test_driver "${GITHUB_REPOSITORY_NAME}"
diff --git a/tools/internal_ci/linux/grpc_xds_url_map_python.sh b/tools/internal_ci/linux/grpc_xds_url_map_python.sh
index bb302c825d7..7316df954f6 100755
--- a/tools/internal_ci/linux/grpc_xds_url_map_python.sh
+++ b/tools/internal_ci/linux/grpc_xds_url_map_python.sh
@@ -17,9 +17,7 @@ set -eo pipefail
 
 # Constants
 readonly GITHUB_REPOSITORY_NAME="grpc"
-# GKE Cluster
-readonly GKE_CLUSTER_NAME="interop-test-psm-basic"
-readonly GKE_CLUSTER_ZONE="us-central1-c"
+readonly TEST_DRIVER_INSTALL_SCRIPT_URL="https://raw.githubusercontent.com/${TEST_DRIVER_REPO_OWNER:-grpc}/grpc/${TEST_DRIVER_BRANCH:-master}/tools/internal_ci/linux/grpc_xds_k8s_install_test_driver.sh"
 ## xDS test client Docker images
 readonly CLIENT_IMAGE_NAME="gcr.io/grpc-testing/xds-interop/python-client"
 readonly FORCE_IMAGE_BUILD="${FORCE_IMAGE_BUILD:-0}"
@@ -130,8 +128,13 @@ run_test() {
 main() {
   local script_dir
   script_dir="$(dirname "$0")"
-  # shellcheck source=tools/internal_ci/linux/grpc_xds_k8s_install_test_driver.sh
-  source "${script_dir}/grpc_xds_k8s_install_test_driver.sh"
+
+  # Source the test driver from the master branch.
+  echo "Sourcing test driver install script from: ${TEST_DRIVER_INSTALL_SCRIPT_URL}"
+  source /dev/stdin <<< "$(curl -s "${TEST_DRIVER_INSTALL_SCRIPT_URL}")"
+
+  activate_gke_cluster GKE_CLUSTER_PSM_BASIC
+  
   set -x
   if [[ -n "${KOKORO_ARTIFACTS_DIR}" ]]; then
     kokoro_setup_test_driver "${GITHUB_REPOSITORY_NAME}"