yet another problem with new overlay fs

It turns out that the new upstream overlay fs requires that the delta and work dirs be under the same mount. So create a $lxcpath/tmpfs and create delta0 and work0 under that. If the user asks for a tmpfs that'll be mounted under $lxcpath/tmpfs and workdir and delta0 both created under that. This isn't heavily tested. But if fixes mounting of 'overlay' fs for me. It's "not backward compatible", since it moves delta0, but that shouldn't matter since ephemeral containers are either destroyed on exit, or re-started with lxc-start. Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com> Acked-by: Stéphane Graber <stgraber@ubuntu.com>

yet another problem with new overlay fs
dd2271e6 · Serge Hallyn · Stéphane Graber · 5fdd4b0c · dd2271e6
Commit dd2271e6 authored Jan 19, 2015 by Serge Hallyn Committed by Stéphane Graber Jan 20, 2015
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lxc-start-ephemeral.in src/lxc/lxc-start-ephemeral.in +11 -12

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--- a/src/lxc/lxc-start-ephemeral.in
+++ b/src/lxc/lxc-start-ephemeral.in
@@ -166,6 +166,7 @@ dest = lxc.Container(os.path.basename(dest_path), args.lxcpath)
 dest.load_config(orig.config_file_name)
 dest.set_config_item("lxc.utsname", dest.name)
 dest.set_config_item("lxc.rootfs", os.path.join(dest_path, "rootfs"))
+print("setting rootfs to .%s.", os.path.join(dest_path, "rootfs"))
 for nic in dest.network:
    if hasattr(nic, 'hwaddr'):
        nic.hwaddr = randomMAC()
@@ -238,34 +239,32 @@ LXC_NAME="%s"

    count = 0
    for entry in overlay_dirs:
-        target = "%s/delta%s" % (dest_path, count)
-        workdir = "%s/work%s" % (dest_path, count)
-        fd.write("mkdir -p %s %s\n" % (target, entry[1]))
+        deltdir = "%s/delta%s" % (tmpdir, count)
+        workdir = "%s/work%s" % (tmpdir, count)
+        fd.write("mkdir -p %s %s\n" % (deltdir, entry[1]))
        if have_new_overlay:
            fd.write("mkdir -p %s\n" % workdir)

        if args.storage_type == "tmpfs":
-            fd.write("mount -n -t tmpfs -o mode=0755 none %s\n" % (target))
-            if have_new_overlay:
-                fd.write("mount -n -t tmpfs -o mode=0755 none %s\n" % (workdir))
+            fd.write("mount -n -t tmpfs -o mode=0755 none %s\n" % (tmpdir))
+            fd.write("mkdir %s\n" % deltdir)
+            fd.write("mkdir %s\n" % workdir)

-        fd.write("getfacl -a %s | setfacl --set-file=- %s || true\n" % (entry[0], target))
+        fd.write("getfacl -a %s | setfacl --set-file=- %s || true\n" % (entry[0], deltdir))
        fd.write("getfacl -a %s | setfacl --set-file=- %s || true\n" % (entry[0], entry[1]))
-        if have_new_overlay:
-            fd.write("getfacl -a %s | setfacl --set-file=- %s || true\n" % (entry[0], workdir))

        if args.union_type == "overlayfs":
            if have_new_overlay:
                fd.write("mount -n -t overlay"
                     " -oupperdir=%s,lowerdir=%s,workdir=%s none %s\n" % (
-                         target,
+                         deltdir,
                         entry[0],
                         workdir,
                         entry[1]))
            else:
                fd.write("mount -n -t overlayfs"
                     " -oupperdir=%s,lowerdir=%s none %s\n" % (
-                         target,
+                         deltdir,
                         entry[0],
                         entry[1]))
        elif args.union_type == "aufs":
@@ -275,7 +274,7 @@ LXC_NAME="%s"

            fd.write("mount -n -t aufs "
                     "-o br=%s=rw:%s=ro,noplink,xino=%s none %s\n" % (
-                         target,
+                         deltdir,
                         entry[0],
                         xino_path,
                         entry[1]))