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NFS
,→Prepare the HN
For NFS mounts to work in the containers with the RHEL5-based kernels you must enable kernel threads in the container by setting <code>kernel.ve_allow_kthreads=1</code> in <code>/etc/sysctl.conf</code>.
RHEL7-based kernels support [https://www.centos.org/docs/5/html/Deployment_Guide-en-US/ch-nfs.html three different NFS protocol versions]:
{{Quote|
NFS version 2 (NFSv2) is older and is widely supported.
NFS version 3 (NFSv3) has more features, including 64bit file handles, Safe Async writes and more robust error handling.
NFS version 4 (NFSv4) works through firewalls and on the Internet, no longer requires portmapper, supports ACLs, and utilizes stateful operations.
Red Hat Enterprise Linux supports NFSv2, NFSv3, and NFSv4 clients, and when mounting a file system via NFS, Red Hat Enterprise Linux uses NFSv3 by default, if the server supports it.
}}
Accordingly, there are three kernel modules: <code>nfs</code> (for NFSv2), <code>nfsv3</code>, and <code>nfsv4</code>. As [[NFS server inside container]] currently only supports NFSv3, it's very likely that you'll need to load <code>nfsv3</code> module for clients.
# modprobe nfs
modprobe nfs
Alternatively, you can add a new line with <code>nfs</code> to your /etc/modules or /etc/modules.conf file.
=== Prepare the container ===
== Mounting NFS ==
Make sure that packages <code>nfs-utils</code> and <code>nfs-utils-lib</code> or similar are installed in a container. Also make sure that the <code>portmap</code> (or <code>rpcbind</code>) service is started, otherwise the mount with default options will fail and require the <code>-nolock</code> option. See the [[NFS#Known issues|known issues]] for more information.
Assuming that you already have NFS server set up at <code>192.168.0.1:/nfs_pub</code>, mounting will be simple
* There are quite a few parameters in NFS, so sometimes it doesn't work due to misconfiguration. We've created a separate page describing such situations: [[NFS doesn't work]].
* Package nfs-common can not be installed. Make sure you start <code>portmap</code> before trying to install nfs-common.
** For Ubuntu/Debian OpenVZ containers, the <code>portmap/rpcbind</code> service may not start automatically. However, you can enable it by editing the <code>/etc/default/nfs-common</code> configuration file.
== See also ==
