diff --git a/Vagrantfile b/Vagrantfile
index a079fea520..1a3dcd90e0 100644
--- a/Vagrantfile
+++ b/Vagrantfile
@@ -101,64 +101,9 @@ Vagrant.configure("2") do |config|
     prl.cpus = vm_num_cpus
   end
 
-  $provision_script = <<SCRIPT
-set -x
-set -e
-set -o pipefail
-
-# Code should go here, rather than tools/provision, only if it is
-# something that we don't want to happen when running provision in a
-# development environment not using Vagrant.
-
-# Set the Ubuntu mirror
-[ ! '#{ubuntu_mirror}' ] || sudo sed -i 's|http://\\(\\w*\\.\\)*archive\\.ubuntu\\.com/ubuntu/\\? |#{ubuntu_mirror} |' /etc/apt/sources.list
-
-# Set the MOTD on the system to have Zulip instructions
-sudo ln -nsf /srv/zulip/tools/setup/dev-motd /etc/update-motd.d/99-zulip-dev
-sudo rm -f /etc/update-motd.d/10-help-text
-sudo dpkg --purge landscape-client landscape-common ubuntu-release-upgrader-core update-manager-core update-notifier-common ubuntu-server
-sudo dpkg-divert --add --rename /etc/default/motd-news
-sudo sh -c 'echo ENABLED=0 > /etc/default/motd-news'
-
-# Set default locale, this prevents errors if the user has another locale set.
-if ! grep -q 'LC_ALL=C.UTF-8' /etc/default/locale; then
-    echo "LC_ALL=C.UTF-8" | sudo tee -a /etc/default/locale
-fi
-
-# Set an environment variable, so that we won't print the virtualenv
-# shell warning (it'll be wrong, since the shell is dying anyway)
-export SKIP_VENV_SHELL_WARNING=1
-
-# End `set -x`, so that the end of provision doesn't look like an error
-# message after a successful run.
-set +x
-
-# Check if the zulip directory is writable
-if [ ! -w /srv/zulip ]; then
-    echo "The vagrant user is unable to write to the zulip directory."
-    echo "To fix this, run the following commands on the host machine:"
-    # sudo is required since our uid is not 1000
-    echo '    vagrant halt -f'
-    echo '    rm -rf /PATH/TO/ZULIP/CLONE/.vagrant'
-    echo '    sudo chown -R 1000:$(id -g) /PATH/TO/ZULIP/CLONE'
-    echo "Replace /PATH/TO/ZULIP/CLONE with the path to where zulip code is cloned."
-    echo "You can resume setting up your vagrant environment by running:"
-    echo "    vagrant up"
-    exit 1
-fi
-# Provision the development environment
-ln -nsf /srv/zulip ~/zulip
-/srv/zulip/tools/provision
-
-# Run any custom provision hooks the user has configured
-if [ -f /srv/zulip/tools/custom_provision ]; then
-    chmod +x /srv/zulip/tools/custom_provision
-    /srv/zulip/tools/custom_provision
-fi
-SCRIPT
-
   config.vm.provision "shell",
     # We want provision to be run with the permissions of the vagrant user.
     privileged: false,
-    inline: $provision_script
+    path: "tools/setup/vagrant-provision",
+    env: { "UBUNTU_MIRROR" => ubuntu_mirror }
 end
diff --git a/tools/setup/vagrant-provision b/tools/setup/vagrant-provision
new file mode 100755
index 0000000000..e26e941e5e
--- /dev/null
+++ b/tools/setup/vagrant-provision
@@ -0,0 +1,55 @@
+#!/usr/bin/env bash
+set -x
+set -e
+set -o pipefail
+
+# Code should go here, rather than tools/provision, only if it is
+# something that we don't want to happen when running provision in a
+# development environment not using Vagrant.
+
+# Set the Ubuntu mirror
+[ ! "$UBUNTU_MIRROR" ] || sudo sed -i 's|http://\(\w*\.\)*archive\.ubuntu\.com/ubuntu/\? |'"$UBUNTU_MIRROR"' |' /etc/apt/sources.list
+
+# Set the MOTD on the system to have Zulip instructions
+sudo ln -nsf /srv/zulip/tools/setup/dev-motd /etc/update-motd.d/99-zulip-dev
+sudo rm -f /etc/update-motd.d/10-help-text
+sudo dpkg --purge landscape-client landscape-common ubuntu-release-upgrader-core update-manager-core update-notifier-common ubuntu-server
+sudo dpkg-divert --add --rename /etc/default/motd-news
+sudo sh -c 'echo ENABLED=0 > /etc/default/motd-news'
+
+# Set default locale, this prevents errors if the user has another locale set.
+if ! grep -q 'LC_ALL=C.UTF-8' /etc/default/locale; then
+    echo "LC_ALL=C.UTF-8" | sudo tee -a /etc/default/locale
+fi
+
+# Set an environment variable, so that we won't print the virtualenv
+# shell warning (it'll be wrong, since the shell is dying anyway)
+export SKIP_VENV_SHELL_WARNING=1
+
+# End `set -x`, so that the end of provision doesn't look like an error
+# message after a successful run.
+set +x
+
+# Check if the zulip directory is writable
+if [ ! -w /srv/zulip ]; then
+    echo "The vagrant user is unable to write to the zulip directory."
+    echo "To fix this, run the following commands on the host machine:"
+    # sudo is required since our uid is not 1000
+    echo '    vagrant halt -f'
+    echo '    rm -rf /PATH/TO/ZULIP/CLONE/.vagrant'
+    # shellcheck disable=SC2016
+    echo '    sudo chown -R 1000:$(id -g) /PATH/TO/ZULIP/CLONE'
+    echo "Replace /PATH/TO/ZULIP/CLONE with the path to where zulip code is cloned."
+    echo "You can resume setting up your vagrant environment by running:"
+    echo "    vagrant up"
+    exit 1
+fi
+# Provision the development environment
+ln -nsf /srv/zulip ~/zulip
+/srv/zulip/tools/provision
+
+# Run any custom provision hooks the user has configured
+if [ -f /srv/zulip/tools/custom_provision ]; then
+    chmod +x /srv/zulip/tools/custom_provision
+    /srv/zulip/tools/custom_provision
+fi