Fix image preloading

images/02-preload/Dockerfile

@@ -1,4 +1,4 @@
 FROM rancher/os-base
-RUN ln -sf /var/lib/rancher/docker/docker /usr/bin/docker
+RUN ln -sf /var/lib/rancher/engine/docker /usr/bin/docker
 COPY preload.sh  /
 CMD ["/preload.sh"]

images/02-preload/preload.sh

@@ -4,6 +4,12 @@ set -e
 BASE=${1:-${PRELOAD_DIR}}
 BASE=${BASE:-/mnt/preload}
 
+if [ "${SYSTEM_IMAGES}" = "true" ]; then
+    docker_bin=system-docker
+else
+    docker_bin=docker
+fi
+
 should_load() {
     file=${1}
     if [[ ${file} =~ \.done$ ]]; then echo false
@@ -26,7 +32,7 @@ if [ -d ${BASE} ]; then
             if [[ ${file} =~ \.t?gz$ ]]; then CAT="${CAT} | gunzip"; fi
             if [[ ${file} =~ \.t?xz$ ]]; then CAT="${CAT} | unxz"; fi
             wait-for-docker
-            CAT="${CAT} | docker load"
+            CAT="${CAT} | ${docker_bin} load"
             echo loading from ${path}
             eval ${CAT} || :
             touch ${path}.done || :

os-config.tpl.yml

@@ -253,6 +253,8 @@ rancher:
       - system-volumes
     preload-system-images:
       image: {{.OS_REPO}}/os-preload:{{.VERSION}}{{.SUFFIX}}
+      environment:
+      - SYSTEM_IMAGES=true
       labels:
         io.rancher.os.detach: "false"
         io.rancher.os.scope: system

tests/preload_test.go

@@ -0,0 +1,23 @@
+package integration
+
+import (
+	. "gopkg.in/check.v1"
+)
+
+func (s *QemuSuite) TestPreload(c *C) {
+	err := s.RunQemu()
+	c.Assert(err, IsNil)
+
+	s.CheckCall(c, `
+docker pull busybox
+sudo docker save -o /var/lib/rancher/preload/system-docker/busybox.tar busybox
+sudo system-docker pull alpine
+sudo system-docker save -o /var/lib/rancher/preload/docker/alpine.tar alpine`)
+
+	s.Reboot(c)
+
+	s.CheckCall(c, `
+sleep 5
+sudo system-docker images | grep busybox
+docker images | grep alpine`)
+}