Re: [zones-discuss] Re: [appliances-discuss] Re: [nfs-discuss] Re: [sysadmin-discuss] NFS server in zones
hi Luke, [0] The only exception is that the kernel NFS server module can't hop from one filesystem to another, so if /export and /export/home are two different partitions, then if you mount /export on a remote-client machine, /export/home appears to be empty. A userspace NFS server-daemon wouldn't necessarily have this limitation, As an aside, note that this limitation is a facet of our existing NFSv4 implementation, and not anything to do with the NFSv4 protocol itself. This functionality, the ability to transparently cross server filesystem boundaries (known as mirror-mounts), *is* supported by the NFSv4 protocol (i.e. NFSv4.0). I have basic support for this working, and once it's cleaned up and extended a little, will hope to be putting it back into our Nevada NFS client later this year. cheers, calum. ___ zones-discuss mailing list zones-discuss@opensolaris.org
[zones-discuss] Re: [appliances-discuss] Re: [nfs-discuss] Re: [sysadmin-discuss] NFS server in zones
On Thu, Feb 15, 2007 at 01:30:44PM -0800, [EMAIL PROTECTED] wrote: Luke Scharf wrote: Why not just run a userland NFS daemon in the zones -- and follow the existing security model? That makes all of the security model questions fall away -- and it also gets fault isolation. There's a slight performance penalty, but you're running a VM-ish environment anyway. Not entirely. Look at OpenAFS, which does just that. There are two issues: 1) You need an open-by-FID (fsid+inode) type of system call, which gets us back to the issue that no single filesystem should have separate sub-directories shared by different zones. 2) You need a bunch of system calls like open(2) but augmented with an argument specifying who to do the operation as. I blogged about (2) here: http://blogs.sun.com/nico/entry/building_filesystem_servers_in_user in the context of hostafs -- a user-land AFS server for serving non-AFS local filesystems. Normally OpenAFS gets around (1) and (2) by implementing the filesystem in user-land, not just the protocol. This means that there's no local access to AFS-shared filesystems. (Hmmm, much of ZFS runs in user-land, so perhaps one could run an all-user-land NFS+ZFS server, but, does anyone really want to build such a thing?) Of course, you still need an implementation of NFS in user-land... This thought did occur to me and if you take it to the logical conclusion, there is no way to restrict which directories or partitions a zone shares if they are accessible inside the zone. Well, this is true, but if you restrict access via an open-by-FID syscall (see (1) above) to filesystems owned only by the zone whence the call is made, then this problem goes away. In practice you can't have NFSv3 (or AFS) service without open-by-FID. For NFSv4 you can get by without it with some minor limitations. This presupposes that root in the zone has access to software to do this...but there have been programs around for over a decade that are standalone NFS clients, so I can't see why there isn't an NFS server equivalent. See above. With respect to performance, there isn't really any serious performance hit at all for applications running in a local zone. They interact directly with the kernel and disk, just like they would if they were running in the global zone. But we're talking about an NFS server in user-land -- surely there'd be a perf hit as compared to NFS service in kernel-land (if nothing else it may complicate server-side zero-copy, but then, you can't have that if you want crypto in the protocol, not without RDDP, IPsec-capable RNICs and channel binding to IPsec, but that's all a long story). Nico -- ___ zones-discuss mailing list zones-discuss@opensolaris.org
[zones-discuss] Re: [appliances-discuss] Re: [nfs-discuss] Re: [sysadmin-discuss] NFS server in zones
On Thu, Feb 15, 2007 at 03:58:38PM -0600, Nicolas Williams wrote: (Hmmm, much of ZFS runs in user-land, I meant that much ZFS code compiles and can run in user-land, not that it actually works that way in production. ___ zones-discuss mailing list zones-discuss@opensolaris.org
[zones-discuss] Re: [appliances-discuss] Re: [nfs-discuss] Re: [sysadmin-discuss] NFS server in zones
On Thu, Feb 15, 2007 at 03:58:38PM -0600, Nicolas Williams wrote: Of course, you still need an implementation of NFS in user-land... Speaking of which, IIRC Sun had a Java NFSv4 server (written by Brent Callaghan, as I recall) that was used during development of the protocol, and there's a python implementation out there: http://www.citi.umich.edu/projects/nfsv4/pynfs/ Nico -- ___ zones-discuss mailing list zones-discuss@opensolaris.org
Re: [zones-discuss] Re: [appliances-discuss] Re: [nfs-discuss] Re: [sysadmin-discuss] NFS server in zones
Luke Scharf wrote: Why not just run a userland NFS daemon in the zones -- and follow the existing security model? That makes all of the security model questions fall away -- Would you clarify that? I don't know how NFS works, but it seems to me that the security enforcement components should be performed in the kernel where there is better protection. That doesn't preclude the rest from living in userland. -- Jeff VICTOR Sun Microsystemsjeff.victor @ sun.com OS AmbassadorSr. Technical Specialist Solaris 10 Zones FAQ:http://www.opensolaris.org/os/community/zones/faq -- ___ zones-discuss mailing list zones-discuss@opensolaris.org
