diff --git a/test/README.md b/test/README.md
index 4e18f175..d7358b86 100644
--- a/test/README.md
+++ b/test/README.md
@@ -57,3 +57,23 @@ DOCKER_OPTS="--host unix:///var/run/docker.sock --host tcp://0.0.0.0:2375"
 ```
 
 to the file `/etc/default/docker`, then restart docker.
+
+## Updating the GCE test image
+
+When a new version of Docker is released, you'll need to update the GCE test image.
+
+To do this, pick a fresh ```TEMPLATE_NAME``` and update any commands in
+```function make_template``` in gce.sh, then run:
+
+```
+./gce.sh make_template
+```
+
+For this you'll need the GCE credentials, which can be found in ```bin/setup-circleci-secrets```,
+which you'll need to decrypt and run (its echos the secrets into know locations):
+
+```
+./bin/setup-circleci-secrets "$SECRET_PASSWORD"
+```
+
+If you don't know the password, ask tom@weave.works.
diff --git a/test/gce.sh b/test/gce.sh
index 09e557fd..f2d7be82 100755
--- a/test/gce.sh
+++ b/test/gce.sh
@@ -11,7 +11,7 @@ set -e
 : ${SSH_KEY_FILE:=$HOME/.ssh/gce_ssh_key}
 : ${PROJECT:=positive-cocoa-90213}
 : ${IMAGE:=ubuntu-14-04}
-: ${TEMPLATE_NAME:=test-template-3}
+: ${TEMPLATE_NAME:=test-template-4}
 : ${ZONE:=us-central1-a}
 : ${NUM_HOSTS:=5}
 SUFFIX=""
@@ -68,10 +68,10 @@ function try_connect {
 function install_docker_on {
 	name=$1
 	ssh -t $name sudo bash -x -s <<EOF
-apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 36A1D7869245C8950F966E92D8576A8BA88D21E9;
-echo deb https://get.docker.io/ubuntu docker main > /etc/apt/sources.list.d/docker.list;
+curl -sSL https://get.docker.com/gpg | sudo apt-key add -
+curl -sSL https://get.docker.com/ | sh
 apt-get update -qq;
-apt-get install -q -y --force-yes --no-install-recommends lxc-docker ethtool;
+apt-get install -q -y --force-yes --no-install-recommends ethtool;
 usermod -a -G docker vagrant;
 echo 'DOCKER_OPTS="-H unix:///var/run/docker.sock -H tcp://0.0.0.0:2375"' >> /etc/default/docker;
 service docker restart