In this article I will teach you how to install OpenVZ on CentOS/RHEL machines.
Table of Contents
What is OpenVZ?
OpenVZ (Open Virtuozzo) is an operating system-level virtualization technology based on the Linux kernel and operating system.
OpenVZ allows a physical server to run multiple isolated operating system instances, called containers, virtual private servers (VPSs),
or virtual environments (VEs).
OpenVZ is similar to FreeBSD jails and Solaris Containers.
Requirements:
CentOS 6 64-bit installed with:
- SELinux and Firewall disabled. containers must be on the same subnet as the host node.
- The node’s IP is 192.168.1.99/24 and the gateway is 192.168.1.1.
- The containers will have 192.168.1.101, 192.168.1.102, etc…
Add the OpenVZ yum repo
# wget -O /etc/yum.repos.d/openvz.repo https://download.openvz.org/openvz.repo
# rpm --import https://download.openvz.org/RPM-GPG-Key-OpenVZ
Ensure the yum repo points to RHEL6 packages
# vi /etc/yum.repos.d/openvz.repo
Install the OpenVZ kernel and ensure it’s the 1st option in grub
# yum install vzkernel # vi /boot/grub/menu.lst
Install the OpenVZ utilities
# yum install vzctl vzquota
Tune /etc/sysctl.conf
# vi /etc/sysctl.conf
net.ipv4.ip_forward = 1 net.ipv4.conf.default.proxy_arp = 0 net.ipv4.conf.all.rp_filter = 1 kernel.sysrq = 1 net.ipv4.conf.default.send_redirects = 1 net.ipv4.conf.all.send_redirects = 0 net.ipv4.icmp_echo_ignore_broadcasts=1 net.ipv4.conf.default.forwarding=1
The last 2 steps are necessary only if you are planning on using veth containers
Create a vmbr0 bridge and add the host’s interface to it
# vi /etc/sysconfig/network-scripts/ifcfg-vmbr0
DEVICE="vmbr0" BOOTPROTO="static" IPV6INIT="no" ONBOOT="yes" TYPE="Bridge" DELAY=0 IPADDR=192.168.1.99 NETMASK=255.255.255.0 GATEWAY=192.168.1.1 # vi /etc/sysconfig/network-scripts/ifcfg-eth0 DEVICE="eth0" ONBOOT="yes" IPV6INIT="no" TYPE="Ethernet" BRIDGE="vmbr0"
Create /etc/vz/vznet.conf with the following content.
This will automatically add/remove the container’s interface to the bridge when you start/stop the container.
# vi /etc/vz/vznet.conf #!/bin/bash EXTERNAL_SCRIPT="/usr/sbin/vznetaddbr"
Create a VENET Container
# vzctl create 101 --ostemplate centos-6-x86_64 --config vswap-1g
Configure the CT
# vzctl set 101 --save --name server101 # vzctl set 101 --save --onboot yes # vzctl set 101 --save --hostname server101.example.com # vzctl set 101 --save --ipadd 192.168.1.101 # vzctl set 101 --save --searchdomain example.com # vzctl set 101 --save --nameserver 8.8.8.8 --nameserver 8.8.4.4 # vzctl set 101 --save --cpus 4 # vzctl set 101 --save --ram 8G # vzctl set 101 --save --swap 4G # vzctl set 101 --save --diskspace 100G # vzctl start 101 # vzctl exec 101 passwd
Done. Enjoy your new VENET container
Create a VETH Container
# vzctl create 102 --ostemplate centos-6-x86_64 --config vswap-1g
Configure the CT
# vzctl set 102 --save --name server102 # vzctl set 102 --save --onboot yes # vzctl set 102 --save --hostname server102.example.com # vzctl set 102 --save --netif_add eth0,,,FE:FF:FF:FF:FF:FF # vzctl set 102 --save --searchdomain example.com # vzctl set 102 --save --nameserver 8.8.8.8 --nameserver 8.8.4.4 # vzctl set 102 --save --cpus 4 # vzctl set 102 --save --ram 8G # vzctl set 102 --save --swap 4G # vzctl set 102 --save --diskspace 100G # vzctl start 102 # vzctl exec 102 passwd
FE:FF:FF:FF:FF:FF will ensure a permanent MAC address on the bridge interface.
(Linux bridges behave strangely. They use the smallest MAC address of all the attached interfaces. If you add a new interface to the bridge with an even smaller MAC, the MAC of the bridge will change causing network interruption until the switch re-learns the new MAC)
Configure the network of a RHEL-based container
# cat << _EOF_ > /vz/root/102/etc/sysconfig/network-scripts/ifcfg-eth0 DEVICE="eth0" HOSTNAME="server102" IPV6INIT="no" MTU="1500" TYPE="Ethernet" ONBOOT=yes BOOTPROTO=static IPADDR=192.168.1.102 NETMASK=255.255.255.0 GATEWAY=192.168.1.1 _EOF_ # vzctl exec 102 /etc/init.d/network restart
Configure the network of a Debian-based container
# cat << _EOF_ > /vz/root/102/etc/network/interfaces auto lo eth0 iface lo inet loopback iface eth0 inet static address 192.168.1.102 netmask 255.255.255.0 gateway 192.168.1.1 _EOF_ # vzctl exec 102 /etc/init.d/networking restart
Done. Enjoy your new VETH container
The information in this article is taken from the official OpenVZ installation guide which can be found here .
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