diff --git a/circle.yml b/circle.yml
index a11d50ff..338fbbe4 100644
--- a/circle.yml
+++ b/circle.yml
@@ -17,13 +17,13 @@ dependencies:
   cache_directories:
     - "~/docker"
   override:
-      - if [[ -e "$WEAVE_BUILD" ]]; then
-          docker load -i $WEAVE_BUILD;
-        else
-          docker pull weaveworks/weave-build;
-          mkdir -p $(dirname "$WEAVE_BUILD");
-          docker save weaveworks/weave-build >$WEAVE_BUILD;
-        fi
+    - if [[ -e "$WEAVE_BUILD" ]]; then
+        docker load -i $WEAVE_BUILD;
+      else
+        docker pull weaveworks/weave-build;
+        mkdir -p $(dirname "$WEAVE_BUILD");
+        docker save weaveworks/weave-build >$WEAVE_BUILD;
+      fi
   post:
     - curl https://sdk.cloud.google.com | bash
     - bin/setup-circleci-secrets "$SECRET_PASSWORD"
@@ -32,9 +32,14 @@ dependencies:
 
 test:
   override:
-    - docker run -v /var/run/docker.sock:/run/docker.sock -v /home/ubuntu:/home/go weaveworks/weave-build
-    - cd $SRCDIR/test; ./gce.sh setup
-    - cd $SRCDIR/test; . ./gce.sh hosts; ./setup.sh
-    - cd $SRCDIR/test; . ./gce.sh hosts; ./run_all.sh
+    - docker run -v /var/run/docker.sock:/run/docker.sock -v /home/ubuntu:/home/go weaveworks/weave-build:
+        parallel: true
+    - cd $SRCDIR/test; ./gce.sh setup:
+        parallel: true
+    - cd $SRCDIR/test; . ./gce.sh hosts; ./setup.sh:
+        parallel: true
+    - cd $SRCDIR/test; . ./gce.sh hosts; ./run_all.sh:
+        parallel: true
   post:
-    - cd $SRCDIR/test; ./gce.sh destroy
+    - cd $SRCDIR/test; ./gce.sh destroy:
+        parallel: true
diff --git a/test/100_cross_hosts_test.sh b/test/100_cross_hosts_test.sh
index 7c8502da..6d9a0e30 100755
--- a/test/100_cross_hosts_test.sh
+++ b/test/100_cross_hosts_test.sh
@@ -10,8 +10,8 @@ start_suite "Ping over cross-host weave network"
 weave_on $HOST1 launch
 weave_on $HOST2 launch $HOST1
 
-weave_on $HOST2 run $C2/24 -t --name=c2 ubuntu
-weave_on $HOST1 run $C1/24 -t --name=c1 ubuntu
+weave_on $HOST2 run $C2/24 -t --name=c2 gliderlabs/alpine /bin/sh
+weave_on $HOST1 run $C1/24 -t --name=c1 gliderlabs/alpine /bin/sh
 assert_raises "exec_on $HOST1 c1 ping -q -c 4 $C2"
 
 end_suite
diff --git a/test/110_encryption_test.sh b/test/110_encryption_test.sh
index 7ba2ebb3..e5099b68 100755
--- a/test/110_encryption_test.sh
+++ b/test/110_encryption_test.sh
@@ -10,8 +10,8 @@ start_suite "Ping over encrypted cross-host weave network"
 weave_on $HOST1 launch -password notverysecure
 weave_on $HOST2 launch -password notverysecure $HOST1
 
-weave_on $HOST2 run $C2/24 -t --name=c2 ubuntu
-weave_on $HOST1 run $C1/24 -t --name=c1 ubuntu
+weave_on $HOST2 run $C2/24 -t --name=c2 gliderlabs/alpine /bin/sh
+weave_on $HOST1 run $C1/24 -t --name=c1 gliderlabs/alpine /bin/sh
 assert_raises "exec_on $HOST1 c1 ping -q -c 4 $C2"
 
 end_suite
diff --git a/test/130_expose_test.sh b/test/130_expose_test.sh
index 8a9917b4..16240f78 100755
--- a/test/130_expose_test.sh
+++ b/test/130_expose_test.sh
@@ -34,7 +34,7 @@ start_suite "exposing weave network to host"
 weave_on $HOST1 launch
 
 for c in $C1 $C2 $C3 $C4; do
-    weave_on $HOST1 run ${c#*:}/24 -t --name=${c%:*} ubuntu
+    weave_on $HOST1 run ${c#*:}/24 -t --name=${c%:*} gliderlabs/alpine /bin/sh
 done
 
 # absence of host connectivity by default
diff --git a/test/200_dns_test.sh b/test/200_dns_test.sh
index d5161beb..b0717349 100755
--- a/test/200_dns_test.sh
+++ b/test/200_dns_test.sh
@@ -10,7 +10,7 @@ start_suite "Resolve names on a single host"
 
 weave_on $HOST1 launch-dns 10.2.254.1/24
 
-weave_on $HOST1 run $C2/24 -t --name=c2 -h $NAME ubuntu
+weave_on $HOST1 run $C2/24 -t --name=c2 -h $NAME gliderlabs/alpine /bin/sh
 weave_on $HOST1 run --with-dns $C1/24 -t --name=c1 aanand/docker-dnsutils /bin/sh
 
 assert_dns_record $HOST1 c1 $NAME $C2
diff --git a/test/210_dns_multicast_test.sh b/test/210_dns_multicast_test.sh
index 91235c53..a315028e 100755
--- a/test/210_dns_multicast_test.sh
+++ b/test/210_dns_multicast_test.sh
@@ -14,7 +14,7 @@ weave_on $HOST2 launch $HOST1
 weave_on $HOST1 launch-dns 10.2.254.1/24 -debug
 weave_on $HOST2 launch-dns 10.2.254.2/24 -debug
 
-weave_on $HOST2 run $C2/24 -t --name=c2 -h $NAME ubuntu
+weave_on $HOST2 run $C2/24 -t --name=c2 -h $NAME gliderlabs/alpine /bin/sh
 weave_on $HOST1 run --with-dns $C1/24 --name=c1 -t aanand/docker-dnsutils /bin/sh
 
 assert_dns_record $HOST1 c1 $NAME $C2
diff --git a/test/220_dns_custom_test.sh b/test/220_dns_custom_test.sh
index 6603d555..35d14d91 100755
--- a/test/220_dns_custom_test.sh
+++ b/test/220_dns_custom_test.sh
@@ -11,7 +11,7 @@ start_suite "Resolve names in custom domain"
 
 weave_on $HOST1 launch-dns 10.2.254.1/24 --domain $DOMAIN.
 
-weave_on $HOST1 run $C2/24 -t --name=c2 -h $NAME ubuntu
+weave_on $HOST1 run $C2/24 -t --name=c2 -h $NAME gliderlabs/alpine /bin/sh
 weave_on $HOST1 run --with-dns $C1/24 -t --name=c1 aanand/docker-dnsutils /bin/sh
 
 assert_dns_record $HOST1 c1 $NAME $C2
diff --git a/test/230_dns_unqualified_test.sh b/test/230_dns_unqualified_test.sh
index 525c48d7..3ceab5fc 100755
--- a/test/230_dns_unqualified_test.sh
+++ b/test/230_dns_unqualified_test.sh
@@ -12,7 +12,7 @@ start_suite "Resolve unqualified names"
 
 weave_on $HOST1 launch-dns 10.2.254.1/24
 
-weave_on $HOST1 run $C1/24 -t --name=c1 -h $NAME ubuntu
+weave_on $HOST1 run $C1/24 -t --name=c1 -h $NAME gliderlabs/alpine /bin/sh
 weave_on $HOST1 run --with-dns $C2/24 -t --name=c2 -h seetwo.$DOMAIN aanand/docker-dnsutils /bin/sh
 weave_on $HOST1 run --with-dns $C3/24 -t --name=c3 --dns-search=weave.local aanand/docker-dnsutils /bin/sh
 
diff --git a/test/240_dns_add_name_test.sh b/test/240_dns_add_name_test.sh
index 20393a5a..45697ec6 100755
--- a/test/240_dns_add_name_test.sh
+++ b/test/240_dns_add_name_test.sh
@@ -11,7 +11,7 @@ start_suite "Add and remove names on a single host"
 
 weave_on $HOST1 launch-dns 10.2.254.1/24
 
-weave_on $HOST1 run $C2/24 -t --name=c2 ubuntu
+weave_on $HOST1 run $C2/24 -t --name=c2 gliderlabs/alpine /bin/sh
 weave_on $HOST1 run --with-dns $C1/24 -t --name=c1 aanand/docker-dnsutils /bin/sh
 
 weave_on $HOST1 dns-add $C2 c2 -h $NAME2
diff --git a/test/400_weave_local_test.sh b/test/400_weave_local_test.sh
index 34d012fc..286f986f 100755
--- a/test/400_weave_local_test.sh
+++ b/test/400_weave_local_test.sh
@@ -9,7 +9,7 @@ run_on $HOST1 sudo ./weave --local reset
 run_on $HOST1 sudo ./weave --local launch
 assert_raises "docker_on $HOST1 ps | grep weave"
 
-run_on $HOST1 sudo ./weave --local run 10.2.6.5/24 -ti --name=c1 ubuntu
+run_on $HOST1 sudo ./weave --local run 10.2.6.5/24 -ti --name=c1 gliderlabs/alpine /bin/sh
 assert_raises "exec_on $HOST1 c1 ifconfig | grep ethwe"
 
 end_suite
diff --git a/test/500_weave_multi_cidr_test.sh b/test/500_weave_multi_cidr_test.sh
index eb8e3ddc..f9cdf3d8 100755
--- a/test/500_weave_multi_cidr_test.sh
+++ b/test/500_weave_multi_cidr_test.sh
@@ -58,7 +58,7 @@ assert_bridge_cidrs() {
 }
 
 # Run container with three cidrs
-CID=$(DOCKER_HOST=tcp://$HOST1:2375 $WEAVE run 10.2.1.1/24 10.2.2.1/24 10.2.3.1/24 -t --name multicidr -h multicidr.weave.local ubuntu | cut -b 1-12)
+CID=$(DOCKER_HOST=tcp://$HOST1:2375 $WEAVE run 10.2.1.1/24 10.2.2.1/24 10.2.3.1/24 -t --name multicidr -h multicidr.weave.local gliderlabs/alpine /bin/sh | cut -b 1-12)
 assert_container_cidrs $HOST1 $CID 10.2.1.1/24 10.2.2.1/24 10.2.3.1/24
 assert_zone_records $HOST1 $CID multicidr.weave.local. 10.2.1.1 10.2.2.1 10.2.3.1
 
diff --git a/test/gce.sh b/test/gce.sh
index 0a42948a..bf632993 100755
--- a/test/gce.sh
+++ b/test/gce.sh
@@ -14,8 +14,8 @@ TEMPLATE_NAME="test-template"
 ZONE=us-central1-a
 NUM_HOSTS=2
 SUFFIX=""
-if [ -n "$CIRCLECI" -a -n "$CIRCLE_SHA1" ]; then
-	SUFFIX="-${CIRCLE_SHA1:0:7}"
+if [ -n "$CIRCLECI" ]; then
+	SUFFIX="-${CIRCLE_BUILD_NUM}-$CIRCLE_NODE_INDEX"
 fi
 
 # Setup authentication
@@ -45,10 +45,9 @@ function internal_ip {
 }
 
 function try_connect {
-	for i in $(seq 0 10); do
-		if ssh -t $1 true; then
-			return
-		fi
+	for i in {0..10}; do
+		ssh -t $1 true && return
+		sleep 2
 	done
 }
 
diff --git a/test/run_all.sh b/test/run_all.sh
index 5ea2755d..7007925d 100755
--- a/test/run_all.sh
+++ b/test/run_all.sh
@@ -24,7 +24,19 @@ check_test_status() {
 # Overwrite assert.sh _assert_cleanup trap with our own
 trap check_test_status EXIT
 
-for t in *_test.sh; do
+# If running on circle, only run the tests for my "shard".
+# CIRCLE_NODE_TOTAL is the total number of shards, and
+# CIRCLE_NODE_INDEX is my index.
+i=0
+TESTS=
+for test in *_test.sh; do
+    if [ -z "$CIRCLECI" ] || [ $(($i % $CIRCLE_NODE_TOTAL)) -eq $CIRCLE_NODE_INDEX ]; then
+          TESTS="$TESTS $test"
+    fi
+    i=$(($i + 1))
+done
+
+for t in $TESTS; do
     echo
     greyly echo "---= Running $t =---"
     . $t