Oskar Stolc's Howto Collection

• use 2 distinct NICs
• ensure connection tracking is off !!!
• add to haproxy.cfg

option http-server-close

• add to /etc/sysctl.conf

net.ipv4.ip_local_port_range = 1024 65000

• If still not good, try the following (or buy a HW load balancer)

net.ipv4.tcp_tw_reuse = 1
net.core.somaxconn = 10000
net.ipv4.tcp_max_syn_backlog = 10000 …

In this blog we will learn how to do server load balancing with HAProxy.

Our example setup will use a two-node active-standby high availability HAProxy cluster configured with three VIPs. Each HAProxy node will have its own stats page for monitoring.

This howto shows how to detect OpenVZ support on the host and in the container.

#!/bin/bash

if [ -f /proc/user_beancounters ] ; then
        envID=$(cat /proc/1/status |grep envID |cut -f 2)
        if [ $envID -eq 0 ] ; then
                echo "OpenVZ Host"
        else
                echo "OpenVZ Guest"
        fi
else
        echo "Not OpenVZ"
fi …

In this blog we will learn how to set up a KVM hypervisor.

The linux kernel itself is the hypervisor. All we need is to install some user space tools for managing VMs.

# yum install kvm libvirt python-virtinst qemu-kvm bridge-utils

Then we need to start the libvirt daemon

# chkconfig libvirtd …

This howto shows how to create an OpenVZ container on ploop

If you want all newly created containers to use ploop add this to /etc/vz/vz.conf

VE_LAYOUT=ploop

If you want to create only one container on ploop add '--layour ploop' to 'vzctl create' command

vzctl create CTID …

This howto shows how to create an OpenVZ container with VENET interface.

Create the container

vzctl create 10221 --ostemplate centos-6-x86_64 --config vswap-1g

Configure the container

vzctl set 10221 --save --name server10221
vzctl set 10221 --save --onboot yes
vzctl set 10221 --save --hostname server10221.example.com
vzctl set 10221 --save --ipadd …