Major revamp.

nixos/overlays/pull.sh

@@ -0,0 +1,36 @@
+source $stdenv/setup
+
+mkdir -p /var/lib/docker
+mkfs.ext4 /dev/vda
+mount -t ext4 /dev/vda /var/lib/docker
+
+modprobe virtio_net
+dhclient eth0
+
+mkdir -p /etc/ssl/certs/
+cp "$certs" "/etc/ssl/certs/"
+
+# from https://github.com/tianon/cgroupfs-mount/blob/master/cgroupfs-mount
+mount -t tmpfs -o uid=0,gid=0,mode=0755 cgroup /sys/fs/cgroup
+cd /sys/fs/cgroup
+for sys in $(awk '!/^#/ { if ($4 == 1) print $1 }' /proc/cgroups); do
+  mkdir -p $sys
+  if ! mountpoint -q $sys; then
+    if ! mount -n -t cgroup -o $sys cgroup $sys; then
+      rmdir $sys || true
+    fi
+  fi
+done
+
+# run docker daemon
+dockerd -H tcp://127.0.0.1:5555 -H unix:///var/run/docker.sock &
+
+until docker ps 2>/dev/null; do
+  printf '.'
+  sleep 1
+done
+
+rm -r $out
+
+docker pull ${imageId}
+docker save ${imageId} > $out