OpenVZ Virtuozzo Containers Wiki - User contributions [en]

Mounting filesystems

2007-12-26T20:42:33Z

Gmturner: make good on promise in preceeding section to refer to /vz as /vz.

== Mounting filesystems within a VE ==

To mount filesystems inside a VE, you have several choices:

* NFS (the VE will be an NFS Client) - see [[NFS]]
* FUSE - see [[FUSE]]
* Bind mount from Hardware Node

=== Bind mount from Hardware Node ===

Recent Linux kernels support an operation called 'bind mounting' which makes part of a mounted filesystem visible at some other mount point. See 'man bind' for more information.

Bind mounts can be used to make directories on the hardware node visible to the VE.

OpenVZ uses two directories. Assuming our VE is numbered 777, these directories are:

$VZROOT/private/777
$VZROOT/root/777

{{Note|<code>$VZROOT</code> is usually <code>/vz</code>, on Debian systems however this is <code>/var/lib/vz</code>. In this document this is further referred to as <code>/vz</code>.}}

The /vz/private directory contains root directory contents. This directory or subdirectory may be symlinked onto a different filesystem, for example:

/vz/private -> /mnt/openvz

Putting VE root directories onto a separate filesystem (not the hardware node root filesystem) is good storage management practice. It protects the Hardware Node root filesystem from being filled up by a VE; this could cause problems on the Hardware Node.

=== Requirement ===

'''On the HN we have a directory '/home' which we wish to make available (shared) to all VEs.'''

You would think that you could bind mount this directory, as in: 'mount --bind /home /vz/private/777/home' but this does not work — the contents of /home cannot be seen within the VE.

This is where the second directory listed above (/vz/root/777) is used. If a VE is not started, this directory is empty. But after starting a VE, this directory contains what the VE sees as its mounted filesystems.

The correct command to issue on the HN is:

mount --bind /home /vz/root/777/home

The VE must be started and the destination directory must exist. The VE will see this directory mounted like this:

# df
Filesystem 1K-blocks Used Available Use% Mounted on
simfs 10485760 298728 10187032 3% /
tmpfs 484712 0 484712 0% /lib/init/rw
tmpfs 484712 0 484712 0% /dev/shm
ext3 117662052 104510764 7174408 94% /home

[[Category:HOWTO]]

Resource management

2007-12-22T11:45:46Z

Gmturner: is it readable yet? does it still say the same thing? :P

'''OpenVZ resource management''' is a set of controls providing per-[[VE]] limits. These limits may be used to encourage VEs to coexist gracefully on a single physical server.

OpenVZ resource management includes these primary controllers:

* [[User beancounters]]
* [[OpenVZ disk quota system]]
* [[CPU Fairscheduler]]
* [[Traffic shaping with tc]]

FIXME: add more text
FIXME: create a right-hand navigation menu for all of the resource management stuff

[[Category:Definitions]]
[[Category:Kernel]]

Resource management

2007-12-22T11:40:34Z

Gmturner: wtf... while i'm at it, just go ballistic and fix everything i can without learning what you are talking about first :)

'''OpenVZ resource management''' is a set of controls providing per-[[VE]] limits. These limits guarantee that multiple VEs can coexist gracefully on a single physical server.

OpenVZ resource management includes these primary controllers:

* [[User beancounters]]
* [[OpenVZ disk quota system]]
* [[CPU Fairscheduler]]
* [[Traffic shaping with tc]]

FIXME: add more text
FIXME: create a right-hand navigation menu for all of the resource management stuff

[[Category:Definitions]]
[[Category:Kernel]]

Resource management

2007-12-22T11:34:23Z

Gmturner: fix wiko

'''OpenVZ resource management''' is a set of controls to provide per-[[VE]] limits and guarantees in a way that multiple VEs will coexist on a single physical server. It consists these primary controllers:

* [[User beancounters]]
* [[OpenVZ disk quota system]]
* [[CPU Fairscheduler]]
* [[Traffic shaping with tc]]

FIXME: add more text
FIXME: create a right-hand navigation menu for all of the resource management stuff

[[Category:Definitions]]
[[Category:Kernel]]