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VPN via the TUN/TAP device

Kernel TUN/TAP support

OpenVZ supports VPN inside a container via kernel TUN/TAP module and device. To allow container #101 to use the TUN/TAP device the following should be done:

Make sure the tun module has been already loaded on the hardware node:

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lsmod | grep tun

If it is not there, use the following command to load tun module:

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modprobe tun

You can also add it into /etc/modules.conf to make ...

There are two steps to configure the csf in vps:

1. Main vps server ( The host server, in which the vps nodes are running) configuration
2. Vps node configuration.

Let's proceed.

1. Main VPS server configuration

Before starting the CSF installation in a node login to the main server (host server) and check whether the following modules are inserted in to the kernel

———
ipt_conntrack
ipt_LOG
ipt_owner
ipt_state
ip_conntrack_ftp
———

You can check it ...

https://server.com:2087/xml-api/restart ... rvice=imap

http://www.ndd.ru/al/openvz/examples.html
http://maxgarrick.com/understanding-ope ... ce-limits/
http://hostingfu.com/article/vzfree-che ... -openvz-ve
http://download.swsoft.com/virtuozzo/vi ... 721013.htm

http://www.kbrandt.com/2008/10/openvz-b ... cript.html
http://www.monitoringexchange.org/cgi-b ... 9.html;d=1

Server Memory Usage (script)

Ever wondered how much memory you are currently using and how close you are to the QoS hard limit?

Here is a simple script that calculates the QoS hard memory limit and the current memory usage:

#!/bin/sh

# Make sure we are running under a VPS system with QoS
if [ ! -f "/proc/user_beancounters" ]; then
echo "File \"/proc/user_beancounters\" does not exist. Make sure this script runs on a VPS system ...

Apache memory limit (RlimitMEM)

If you are using cPanel/WHM then you've got an option in your WHM to limit memory usage by apache processes (RLimitMEM), the option is under Security -> Modify Apache Memory Usage.

This option executes the script: /scripts/apachelimits. It works fine on dedicated systems, it reads the /proc/meminfo file for the currently installed memory and sets the limit accordingly.

Unfortunately the script is useless on a VPS, since a VPS uses a ...

http://wiki.openvz.org/UBC

vmguarpages: memory allocation guarantee.
This parameter controls how much memory is available to the Virtual Private Server (i.e. how much memory its applications can allocate by malloc(3) or other standard Linux memory allocation mechanisms). The more clients are served or the more "heavy" the application is, the more memory it needs.

The amount of memory that Virtual Private Server's applications are guaranteed to be able to allocate is specified as the barrier of vmguarpages parameter. ...

#vzctl enter 270
enter into VE 270 failed
Unable to open pty: No such file or directory

Execute following commands to create tty and pty devices:

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vzctl exec 270 /sbin/MAKEDEV pty
vzctl exec 270 /sbin/MAKEDEV tty


Sometimes, after "Fix Centos Dev" command, following should be executed:

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vzctl exec 101 MAKEDEV ptmx

To change hostname of the currently existing virtual machine, use following command:

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vzctl set VMID --hostname srv1.domain.com --save

To add/remove IP from the ...