diff --git a/prow.sh b/prow.sh
index b09c29200..fe23cf516 100755
--- a/prow.sh
+++ b/prow.sh
@@ -136,6 +136,9 @@ kind_version_default () {
     case "${CSI_PROW_KUBERNETES_VERSION}" in
         latest|master)
             echo main;;
+        1.21*|release-1.21)
+            # TODO: replace this special case once the next KinD release supports 1.21.
+            echo main;;
         *)
             echo v0.10.0;;
     esac
@@ -159,11 +162,6 @@ kindest/node:v1.14.10@sha256:3fbed72bcac108055e46e7b4091eb6858ad628ec51bf693c21f
 # Use kind node-image --type=bazel by default, but allow to disable that.
 configvar CSI_PROW_USE_BAZEL true "use Bazel during 'kind node-image' invocation"
 
-# Work directory. It has to allow running executables, therefore /tmp
-# is avoided. Cleaning up after the script is intentionally left to
-# the caller.
-configvar CSI_PROW_WORK "$(mkdir -p "$GOPATH/pkg" && mktemp -d "$GOPATH/pkg/csiprow.XXXXXXXXXX")" "work directory"
-
 # By default, this script tests sidecars with the CSI hostpath driver,
 # using the install_csi_driver function. That function depends on
 # a deployment script that it searches for in several places:
@@ -190,8 +188,8 @@ configvar CSI_PROW_WORK "$(mkdir -p "$GOPATH/pkg" && mktemp -d "$GOPATH/pkg/csip
 #   CSI_PROW_DEPLOYMENT variable can be set in the
 #   .prow.sh of each component when there are breaking changes
 #   that require using a non-default deployment. The default
-#   is a deployment named "kubernetes-x.yy" (if available),
-#   otherwise "kubernetes-latest".
+#   is a deployment named "kubernetes-x.yy${CSI_PROW_DEPLOYMENT_SUFFIX}" (if available),
+#   otherwise "kubernetes-latest${CSI_PROW_DEPLOYMENT_SUFFIX}".
 #   "none" disables the deployment of the hostpath driver.
 #
 # When no deploy script is found (nothing in `deploy` directory,
@@ -203,6 +201,7 @@ configvar CSI_PROW_WORK "$(mkdir -p "$GOPATH/pkg" && mktemp -d "$GOPATH/pkg/csip
 configvar CSI_PROW_DRIVER_VERSION "v1.3.0" "CSI driver version"
 configvar CSI_PROW_DRIVER_REPO https://github.com/kubernetes-csi/csi-driver-host-path "CSI driver repo"
 configvar CSI_PROW_DEPLOYMENT "" "deployment"
+configvar CSI_PROW_DEPLOYMENT_SUFFIX "" "additional suffix in kubernetes-x.yy[suffix].yaml files"
 
 # The install_csi_driver function may work also for other CSI drivers,
 # as long as they follow the conventions of the CSI hostpath driver.
@@ -361,10 +360,23 @@ configvar CSI_SNAPSHOTTER_VERSION "$(default_csi_snapshotter_version)" "external
 # to all the K8s versions we test against
 configvar CSI_PROW_E2E_SKIP 'Disruptive|different\s+node' "tests that need to be skipped"
 
-# This is the directory for additional result files. Usually set by Prow, but
-# if not (for example, when invoking manually) it defaults to the work directory.
-configvar ARTIFACTS "${CSI_PROW_WORK}/artifacts" "artifacts"
-mkdir -p "${ARTIFACTS}"
+# This creates directories that are required for testing.
+ensure_paths () {
+    # Work directory. It has to allow running executables, therefore /tmp
+    # is avoided. Cleaning up after the script is intentionally left to
+    # the caller.
+    configvar CSI_PROW_WORK "$(mkdir -p "$GOPATH/pkg" && mktemp -d "$GOPATH/pkg/csiprow.XXXXXXXXXX")" "work directory"
+
+    # This is the directory for additional result files. Usually set by Prow, but
+    # if not (for example, when invoking manually) it defaults to the work directory.
+    configvar ARTIFACTS "${CSI_PROW_WORK}/artifacts" "artifacts"
+    mkdir -p "${ARTIFACTS}"
+
+    # For additional tools.
+    CSI_PROW_BIN="${CSI_PROW_WORK}/bin"
+    mkdir -p "${CSI_PROW_BIN}"
+    PATH="${CSI_PROW_BIN}:$PATH"
+}
 
 run () {
     echo "$(date) $(go version | sed -e 's/.*version \(go[^ ]*\).*/\1/') $(if [ "$(pwd)" != "${REPO_DIR}" ]; then pwd; fi)\$" "$@" >&2
@@ -384,11 +396,6 @@ die () {
     exit 1
 }
 
-# For additional tools.
-CSI_PROW_BIN="${CSI_PROW_WORK}/bin"
-mkdir -p "${CSI_PROW_BIN}"
-PATH="${CSI_PROW_BIN}:$PATH"
-
 # Ensure that PATH has the desired version of the Go tools, then run command given as argument.
 # Empty parameter uses the already installed Go. In Prow, that version is kept up-to-date by
 # bumping the container image regularly.
@@ -647,9 +654,9 @@ find_deployment () {
 
     # Ignore: See if you can use ${variable//search/replace} instead.
     # shellcheck disable=SC2001
-    file="$dir/kubernetes-$(echo "${CSI_PROW_KUBERNETES_VERSION}" | sed -e 's/\([0-9]*\)\.\([0-9]*\).*/\1.\2/')/deploy.sh"
+    file="$dir/kubernetes-$(echo "${CSI_PROW_KUBERNETES_VERSION}" | sed -e 's/\([0-9]*\)\.\([0-9]*\).*/\1.\2/')${CSI_PROW_DEPLOYMENT_SUFFIX}/deploy.sh"
     if ! [ -e "$file" ]; then
-        file="$dir/kubernetes-latest/deploy.sh"
+        file="$dir/kubernetes-latest${CSI_PROW_DEPLOYMENT_SUFFIX}/deploy.sh"
         if ! [ -e "$file" ]; then
             return 1
         fi
@@ -1098,6 +1105,9 @@ main () {
     local images ret
     ret=0
 
+    # Set up work directory.
+    ensure_paths
+
     images=
     if ${CSI_PROW_BUILD_JOB}; then
         # A successful build is required for testing.
@@ -1259,6 +1269,9 @@ gcr_cloud_build () {
     # Required for "docker buildx build --push".
     gcloud auth configure-docker
 
+    # Might not be needed here, but call it just in case.
+    ensure_paths
+
     if find . -name Dockerfile | grep -v ^./vendor | xargs --no-run-if-empty cat | grep -q ^RUN; then
         # Needed for "RUN" steps on non-linux/amd64 platforms.
         # See https://github.com/multiarch/qemu-user-static#getting-started
diff --git a/pull-test.sh b/pull-test.sh
new file mode 100755
index 000000000..b019c1776
--- /dev/null
+++ b/pull-test.sh
@@ -0,0 +1,32 @@
+#! /bin/sh
+
+# Copyright 2021 The Kubernetes Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This script is called by pull Prow jobs for the csi-release-tools
+# repo to ensure that the changes in the PR work when imported into
+# some other repo.
+
+set -ex
+
+# It must be called inside the updated csi-release-tools repo.
+CSI_RELEASE_TOOLS_DIR="$(pwd)"
+
+# Update the other repo.
+cd "$PULL_TEST_REPO_DIR"
+git subtree pull --squash --prefix=release-tools "$CSI_RELEASE_TOOLS_DIR" master
+git log -n2
+
+# Now fall through to testing.
+exec ./.prow.sh