diff --git a/.zuul.yaml b/.zuul.yaml
index 7494d9eca2..ff5f491c1d 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -238,22 +238,20 @@
               - playbooks/zuul-migrate/.*
             nodeset: ubuntu-xenial
             timeout: 4800  # 80 minutes
-            vars:
+            vars: &zuul_tox_vars
                 test_setup_environment:
                     ZUUL_TEST_ROOT: /tmp/zuul-test
+                    YARN_REGISTRY: "https://{{ zuul_site_mirror_fqdn }}:4443/registry.npmjs"
                 tox_environment:
                     ZUUL_TEST_ROOT: /tmp/zuul-test
+                    YARN_REGISTRY: "https://{{ zuul_site_mirror_fqdn }}:4443/registry.npmjs"
         - tox-py38:
             irrelevant-files:
               - zuul/cmd/migrate.py
               - playbooks/zuul-migrate/.*
             timeout: 4800  # 80 minutes
             nodeset: ubuntu-bionic
-            vars:
-                test_setup_environment:
-                    ZUUL_TEST_ROOT: /tmp/zuul-test
-                tox_environment:
-                    ZUUL_TEST_ROOT: /tmp/zuul-test
+            vars: *zuul_tox_vars
         - zuul-build-dashboard-openstack-whitelabel
         - zuul-build-dashboard-software-factory
         - zuul-build-dashboard-opendev
@@ -290,22 +288,14 @@
               - playbooks/zuul-migrate/.*
             nodeset: ubuntu-xenial
             timeout: 4800  # 80 minutes
-            vars:
-                test_setup_environment:
-                    ZUUL_TEST_ROOT: /tmp/zuul-test
-                tox_environment:
-                    ZUUL_TEST_ROOT: /tmp/zuul-test
+            vars: *zuul_tox_vars
         - tox-py38:
             irrelevant-files:
               - zuul/cmd/migrate.py
               - playbooks/zuul-migrate/.*
             timeout: 4800  # 80 minutes
             nodeset: ubuntu-bionic
-            vars:
-                test_setup_environment:
-                    ZUUL_TEST_ROOT: /tmp/zuul-test
-                tox_environment:
-                    ZUUL_TEST_ROOT: /tmp/zuul-test
+            vars: *zuul_tox_vars
         - zuul-build-dashboard
         - nodejs-run-lint:
             vars:
diff --git a/tools/pip.sh b/tools/pip.sh
index de9724f4e9..914c7ffe74 100755
--- a/tools/pip.sh
+++ b/tools/pip.sh
@@ -42,8 +42,18 @@ then
     mkdir -p zuul/web/static
     ln -sfn ../zuul/web/static web/build
     pushd web/
-        yarn install
+        if [[ -n "${YARN_REGISTRY}" ]]
+        then
+            echo "Using yarn registry: ${YARN_REGISTRY}"
+            sed -i "s#https://registry.yarnpkg.com#${YARN_REGISTRY}#" yarn.lock
+        fi
+        yarn install --verbose
         yarn build
+        if [[ -n "${YARN_REGISTRY}" ]]
+        then
+            echo "Resetting yarn registry"
+            sed -i "s#${YARN_REGISTRY}#https://registry.yarnpkg.com#" yarn.lock
+        fi
     popd
 fi
 pip install $*
diff --git a/tox.ini b/tox.ini
index f7ee8ea2a9..5742d83d9b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -23,6 +23,7 @@ passenv =
   OS_LOG_DEFAULTS
   OS_STDERR_CAPTURE
   OS_STDOUT_CAPTURE
+  YARN_REGISTRY
   ZUUL_MYSQL_HOST
   ZUUL_POSTGRES_HOST
   ZUUL_TEST_ROOT