[lxc-devel] [PATCH RFC] yet another problem with new overlay fs

[Stéphane Graber]

On Mon, Jan 19, 2015 at 05:06:55AM +0000, Serge Hallyn wrote:
> 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 at ubuntu.com>

Looks fine to me

Acked-by: Stéphane Graber <stgraber at ubuntu.com>

> ---
>  src/lxc/lxc-start-ephemeral.in | 23 +++++++++++------------
>  1 file changed, 11 insertions(+), 12 deletions(-)
> 
> diff --git a/src/lxc/lxc-start-ephemeral.in b/src/lxc/lxc-start-ephemeral.in
> index 36e2579..66abe56 100644
> --- 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]))
> -- 
> 2.1.0
> 
> _______________________________________________
> lxc-devel mailing list
> lxc-devel at lists.linuxcontainers.org
> http://lists.linuxcontainers.org/listinfo/lxc-devel

-- 
Stéphane Graber
Ubuntu developer
http://www.ubuntu.com
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