diff --git a/.circleci/config.yml b/.circleci/config.yml
index 7ae45522..8af6a4d0 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -150,8 +150,8 @@ jobs:
           command: |
             if ! [[ -z "${SYSTEM_TESTS_ENCRYPTION_KEY}" ]]; then
               for encrypted_key in .circleci/*.json.enc; do
-                openssl aes-256-cbc -d -in $encrypted_key
-                  -out $(echo $encrypted_key | sed 's/\.enc//')
+                openssl aes-256-cbc -d -in $encrypted_key \
+                  -out $(echo $encrypted_key | sed 's/\.enc//') \
                   -k "${SYSTEM_TESTS_ENCRYPTION_KEY}"
               done
             fi
diff --git a/.kokoro/common.cfg b/.kokoro/common.cfg
index 4e3151f6..bf91c1bd 100644
--- a/.kokoro/common.cfg
+++ b/.kokoro/common.cfg
@@ -16,7 +16,7 @@ build_file: "nodejs-dlp/.kokoro/trampoline.sh"
 # Configure the docker image for kokoro-trampoline.
 env_vars: {
     key: "TRAMPOLINE_IMAGE"
-    value: "gcr.io/cloud-devrel-kokoro-resources/node:10"
+    value: "gcr.io/cloud-devrel-kokoro-resources/node:10-user"
 }
 env_vars: {
     key: "TRAMPOLINE_BUILD_FILE"
diff --git a/.kokoro/continuous/node10/common.cfg b/.kokoro/continuous/node10/common.cfg
index 4e3151f6..bf91c1bd 100644
--- a/.kokoro/continuous/node10/common.cfg
+++ b/.kokoro/continuous/node10/common.cfg
@@ -16,7 +16,7 @@ build_file: "nodejs-dlp/.kokoro/trampoline.sh"
 # Configure the docker image for kokoro-trampoline.
 env_vars: {
     key: "TRAMPOLINE_IMAGE"
-    value: "gcr.io/cloud-devrel-kokoro-resources/node:10"
+    value: "gcr.io/cloud-devrel-kokoro-resources/node:10-user"
 }
 env_vars: {
     key: "TRAMPOLINE_BUILD_FILE"
diff --git a/.kokoro/continuous/node6/common.cfg b/.kokoro/continuous/node6/common.cfg
index 71325a7f..c2fa30aa 100644
--- a/.kokoro/continuous/node6/common.cfg
+++ b/.kokoro/continuous/node6/common.cfg
@@ -16,7 +16,7 @@ build_file: "nodejs-dlp/.kokoro/trampoline.sh"
 # Configure the docker image for kokoro-trampoline.
 env_vars: {
     key: "TRAMPOLINE_IMAGE"
-    value: "gcr.io/cloud-devrel-kokoro-resources/node:6"
+    value: "gcr.io/cloud-devrel-kokoro-resources/node:6-user"
 }
 env_vars: {
     key: "TRAMPOLINE_BUILD_FILE"
diff --git a/.kokoro/continuous/node8/common.cfg b/.kokoro/continuous/node8/common.cfg
index 99ce4011..351e2e98 100644
--- a/.kokoro/continuous/node8/common.cfg
+++ b/.kokoro/continuous/node8/common.cfg
@@ -16,7 +16,7 @@ build_file: "nodejs-dlp/.kokoro/trampoline.sh"
 # Configure the docker image for kokoro-trampoline.
 env_vars: {
     key: "TRAMPOLINE_IMAGE"
-    value: "gcr.io/cloud-devrel-kokoro-resources/node:8"
+    value: "gcr.io/cloud-devrel-kokoro-resources/node:8-user"
 }
 env_vars: {
     key: "TRAMPOLINE_BUILD_FILE"
diff --git a/.kokoro/docs.sh b/.kokoro/docs.sh
index 1d288f3d..3af31934 100755
--- a/.kokoro/docs.sh
+++ b/.kokoro/docs.sh
@@ -16,6 +16,8 @@
 
 set -xeo pipefail
 
+export NPM_CONFIG_PREFIX=/home/node/.npm-global
+
 cd $(dirname $0)/..
 
 npm install
diff --git a/.kokoro/lint.sh b/.kokoro/lint.sh
index 9d29203e..7c2ea2a2 100755
--- a/.kokoro/lint.sh
+++ b/.kokoro/lint.sh
@@ -16,6 +16,8 @@
 
 set -xeo pipefail
 
+export NPM_CONFIG_PREFIX=/home/node/.npm-global
+
 cd $(dirname $0)/..
 
 npm install
diff --git a/.kokoro/presubmit/node10/common.cfg b/.kokoro/presubmit/node10/common.cfg
index 4e3151f6..bf91c1bd 100644
--- a/.kokoro/presubmit/node10/common.cfg
+++ b/.kokoro/presubmit/node10/common.cfg
@@ -16,7 +16,7 @@ build_file: "nodejs-dlp/.kokoro/trampoline.sh"
 # Configure the docker image for kokoro-trampoline.
 env_vars: {
     key: "TRAMPOLINE_IMAGE"
-    value: "gcr.io/cloud-devrel-kokoro-resources/node:10"
+    value: "gcr.io/cloud-devrel-kokoro-resources/node:10-user"
 }
 env_vars: {
     key: "TRAMPOLINE_BUILD_FILE"
diff --git a/.kokoro/presubmit/node6/common.cfg b/.kokoro/presubmit/node6/common.cfg
index 71325a7f..c2fa30aa 100644
--- a/.kokoro/presubmit/node6/common.cfg
+++ b/.kokoro/presubmit/node6/common.cfg
@@ -16,7 +16,7 @@ build_file: "nodejs-dlp/.kokoro/trampoline.sh"
 # Configure the docker image for kokoro-trampoline.
 env_vars: {
     key: "TRAMPOLINE_IMAGE"
-    value: "gcr.io/cloud-devrel-kokoro-resources/node:6"
+    value: "gcr.io/cloud-devrel-kokoro-resources/node:6-user"
 }
 env_vars: {
     key: "TRAMPOLINE_BUILD_FILE"
diff --git a/.kokoro/presubmit/node8/common.cfg b/.kokoro/presubmit/node8/common.cfg
index 99ce4011..351e2e98 100644
--- a/.kokoro/presubmit/node8/common.cfg
+++ b/.kokoro/presubmit/node8/common.cfg
@@ -16,7 +16,7 @@ build_file: "nodejs-dlp/.kokoro/trampoline.sh"
 # Configure the docker image for kokoro-trampoline.
 env_vars: {
     key: "TRAMPOLINE_IMAGE"
-    value: "gcr.io/cloud-devrel-kokoro-resources/node:8"
+    value: "gcr.io/cloud-devrel-kokoro-resources/node:8-user"
 }
 env_vars: {
     key: "TRAMPOLINE_BUILD_FILE"
diff --git a/.kokoro/samples-test.sh b/.kokoro/samples-test.sh
index 93af79aa..76edbbbb 100755
--- a/.kokoro/samples-test.sh
+++ b/.kokoro/samples-test.sh
@@ -16,6 +16,8 @@
 
 set -xeo pipefail
 
+export NPM_CONFIG_PREFIX=/home/node/.npm-global
+
 # Setup service account credentials.
 export GOOGLE_APPLICATION_CREDENTIALS=${KOKORO_GFILE_DIR}/service-account.json
 export GCLOUD_PROJECT=long-door-651
diff --git a/.kokoro/system-test.sh b/.kokoro/system-test.sh
index 299032dc..a76c3ab4 100755
--- a/.kokoro/system-test.sh
+++ b/.kokoro/system-test.sh
@@ -16,11 +16,18 @@
 
 set -xeo pipefail
 
+export NPM_CONFIG_PREFIX=/home/node/.npm-global
+
 # Setup service account credentials.
 export GOOGLE_APPLICATION_CREDENTIALS=${KOKORO_GFILE_DIR}/service-account.json
 
 cd $(dirname $0)/..
 
+# Run a pre-test hook, if a pre-system-test.sh is in the project
+if [ -f .kokoro/pre-system-test.sh ]; then
+    . .kokoro/pre-system-test.sh
+fi
+
 npm install
 
 npm run system-test
diff --git a/.kokoro/test.sh b/.kokoro/test.sh
index 7f49f6d3..51f29589 100755
--- a/.kokoro/test.sh
+++ b/.kokoro/test.sh
@@ -16,6 +16,8 @@
 
 set -xeo pipefail
 
+export NPM_CONFIG_PREFIX=/home/node/.npm-global
+
 cd $(dirname $0)/..
 
 npm install