From Linux NFS

from CITI documentation.

Contents 1 NFSv4 configuration 1.1 Base configuration 1.2 Exporting directories 1.3 RPC Processes 1.4 NFS Installation details 1.4.1 openSUSE 1.4.2 Ubuntu 1.4.3 Needed on both client and server on both openSUSE and Ubuntu 1.5 Debugging 1.6 A Real Life Example 1.7 Troubleshooting 1.8 References

NFSv4 configuration

Base configuration

This section may be skipped on most recent distribution. If so, go here

You should have already built and installed the kernel and user utilities and setup krb5.

The following steps need only be done once. It maybe skipped most recent distribution.

Add the following lines to /etc/fstab to mount the rpc_pipefs and nfsd filesystems automatically:

rpc_pipefs	/var/lib/nfs/rpc_pipefs	rpc_pipefs	defaults	0	0
nfsd	/proc/fs/nfsd	nfsd	defaults	0	0

and create the mountpoint for rpc_pipefs, and mount both filesystems:

• mkdir /var/lib/nfs/rpc_pipefs
• mount rpc_pipefs
• mount nfsd

Modify the fstab line for filesystem you plan to export on the server to add the "acl" option to the mount options.

Create a directory to export on the server:

• mkdir /export
• chmod a+rwxt /export

The following steps need to be performed on every boot; this should really be done by init scripts. The necessary init scripts already exist in recent Fedora distributions. See also debian/nfs-common.init and debian/nfs-kernel-server.init in the patched nfs-utils tarball for example init scripts.

On your server, run rpc.mountd, rpc.svcgssd, rpc.idmapd, and rpc.nfsd:

rpc.mountd
rpc.idmapd
rpc.svcgssd   -> this is obsolete as of nfs-utils version 1.0.8-1
rpc.nfsd 8

1. 1. 1. Feb 2012: I've added some updates on this in the below

On the client, run rpc.gssd and rpc.idmapd:

rpc.gssd -m
rpc.idmapd

Exporting directories

Export your server directory (in this case, to anyone, using any authentication flavor), by adding the following lines to /etc/exports

/export  gss/krb5(rw,fsid=0,insecure,no_subtree_check)
/export  gss/krb5i(rw,fsid=0,insecure,no_subtree_check)
/export  gss/krb5p(rw,fsid=0,insecure,no_subtree_check)

and then running

exportfs -r

(Note that if your server is connected to the internet the first line will give everyone in the world read and write access to /export and (with a little work) to anything on the same disk partition as /export! See the exports man page for more information.)

To access this export from a client:

Create a mountpoint on your client:

mkdir /mnt/nfs4/

and mount the server:

mount -t nfs4 yourserver:/export /mnt/nfs4/

or, to mount with kerberos,

mount -t nfs4 -o sec=krb5 yourserver:/export /mnt/nfs4/

Play around with the mounted filesystem:

cd /mnt/nfs4/
echo "Hello World!" >FOO
cat FOO
getfacl FOO

etc.

To mount a filesystem using krb5, provide the "-osec=krb5" option to mount. To export a filesystem using krb5, export it to the special client named "gss/krb5". Replace "krb5" by "krb5i" or "krb5p" for integrity or for privacy, respectively. The -osec= options should also work for NFSv3 exports and mounts.

Exporting and mounting can be automated using /etc/fstab and /etc/exports; see the man pages fstab(5) and exports(5).

Technical note: NFSv4 no longer has a separate "mount" protocol. Instead of exporting a number of distinct exports, an NFSv4 client sees the NFSv4 server's exports as existing inside a single filesystem, called the nfsv4 "pseudofilesystem".

The linux implementation allows you to designate a real filesystem as the pseudofilesystem, identifying that export with the fsid=0 option; we no longer recommend this. Instead, on any recent linux distribution, just list exports in /etc/exports exactly as you would for NFSv2 or NFSv3.

RPC Processes

1. openSUSE after starting the nfs server

ps aux | grep rpc

root 1231 0.0 0.1 2356 764 ? Ss 08:20 0:00 /sbin/rpcbind

root 3737 0.0 0.0 0 0 ? S< 08:28 0:00 [rpciod]

root 5215 0.0 0.2 3684 1208 ? Ss 09:26 0:00 /usr/sbin/rpc.svcgssd

root 5223 0.0 0.0 2416 344 ? Ss 09:26 0:00 /usr/sbin/rpc.idmapd

root 5227 0.0 0.1 2976 748 ? Ss 09:26 0:00 /usr/sbin/rpc.mountd --no-nfs-version 2 --no-nfs-version 3 (note the lack of gssd)

2. On both openSUSE (after calling rpc.gssd) and Ubuntu with all the necessary processes for successfully exporting the directory with -o sec=krb5<flavour>

ps aux | grep rpc

root 1231 0.0 0.1 2356 764 ? Ss 08:20 0:00 /sbin/rpcbind

root 3737 0.0 0.0 0 0 ? S< 08:28 0:00 [rpciod]

root 5215 0.0 0.2 3684 1208 ? Ss 09:26 0:00 /usr/sbin/rpc.svcgssd

root 5223 0.0 0.0 2416 344 ? Ss 09:26 0:00 /usr/sbin/rpc.idmapd

root 5227 0.0 0.1 2976 748 ? Ss 09:26 0:00 /usr/sbin/rpc.mountd --no-nfs-version 2 --no-nfs-version 3

root 5294 0.0 0.0 3816 428 ? Ss 09:31 0:00 rpc.gssd

NFS Installation details

openSUSE

Packages: zypper in nfs-kernel-server nfs-client nfsidmap limal-nfs-server

Configuration (Or use the excellent Yast NFS-Server Module) /etc/sysconfig/nfs

USE_KERNEL_NFSD_NUMBER="4"

MOUNTD_PORT=""

NFS_SECURITY_GSS="yes"

NFS3_SERVER_SUPPORT="no"

NFS4_SUPPORT="yes"

SM_NOTIFY_OPTIONS=""

NFS_START_SERVICES="yes"

STATD_OPTIONS=""

NFSV4LEASETIME=""

RPC_PIPEFS_DIR=""

SVCGSSD_OPTIONS=""

NFSD_OPTIONS=""

Ubuntu

Packages:

apt-get install nfs-common nfs-kernel-server (you may also need to do a: modprobe nfs before starting the nfs server)

Configuration

/etc/default/nfs-common

NEED_STATD=

STATDOPTS=

NEED_IDMAPD=yes

NEED_GSSD=yes

/etc/default/nfs-kernel-server

RPCNFSDCOUNT=8

RPCNFSDPRIORITY=0

RPCMOUNTDOPTS=--manage-gids

NEED_SVCGSSD=yes

RPCSVCGSSDOPTS=

RPCNFSDOPTS=

Needed on both client and server on both openSUSE and Ubuntu

/etc/idmapd.conf

[General]

Verbosity = 0

Pipefs-Directory = /var/lib/nfs/rpc_pipefs

Domain = hh3.site //or whatever your domain is

[Mapping]

Nobody-User = nobody

Nobody-Group = nogroup

Debugging

Run rpc.idmapd -fvvv and rpc.gssd -fvvv in separate terminals. They will tell you in no uncertain terms when you've got it wrong. Please see this screenshot:

http://3.bp.blogspot.com/-PLpbJDP1vCQ/TygMlNU6k8I/AAAAAAAAAGE/lVXsw6iGrS0/s1600/krb5-ubuntu3.png

A Real Life Example

hh3.hh3.site is the nfs server and HH6$@HH3.SITE is the machine principal for the client. On the client, we issue a:

mount -t nfs4 hh3:/foo /bar -o sec=krb5

Here is the log on the KDC:

Kerberos: ENC-TS Pre-authentication succeeded -- HH6$@HH3.SITE using arcfour-hmac-md5

Kerberos: AS-REQ authtime: 2012-02-06T19:44:47 starttime: unset endtime: 2012-02-07T05:44:47 renew till: 2012-02-07T19:44:47

Kerberos: Client supported enctypes: aes256-cts-hmac-sha1-96, aes128-cts-hmac-sha1-96, des3-cbc- sha1, arcfour-hmac-md5, des-cbc-crc, des-cbc-md5, des-cbc-md4, using arcfour-hmac-md5/arcfour-hmac-md5

Kerberos: Requested flags: renewable-ok

Kerberos: TGS-REQ HH6$@HH3.SITE from ipv4:192.168.1.10:45421 for nfs/hh3.hh3.site@HH3.SITE [canonicalize, renewable]

Kerberos: TGS-REQ authtime: 2012-02-06T19:44:47 starttime: 2012-02-06T19:44:47 endtime: 2012-02-07T05:44:47 renew till: 20

The nfs server has identified itself, here are the keys in its keytab:

klist -ke /etc/krb5.keytab Keytab name: WRFILE:/etc/krb5.keytab KVNO Principal

---

---------

  1 nfs/hh3.hh3.site@HH3.SITE (arcfour-hmac)  
  1 HH3$@hh3.site (arcfour-hmac)

Troubleshooting

http://wiki.linux-nfs.org/wiki/index.php?title=Troubleshooting

References

1. This wiki:

http://wiki.linux-nfs.org/wiki/index.php/Nfsv4_configuration

2. man rpc.gssd(8)

http://linux.die.net/man/8/rpc.gssd

3. A hands on practical using modest hardware. Includes screenshots. openSUSE specific.

http://linuxcostablanca.blogspot.com/p/samba-4.html

4. The same as (3) but with Ubuntu specific differences

http://linuxcostablanca.blogspot.com/2012/01/samba-4-ubuntu.html

5. The latest unofficial version of this wiki page. Any new findings, I'll post there.

http://linuxcostablanca.blogspot.com/2012/02/nfsv4-myths-and-legends.html