RedHat / CentOS 6 Bonding

Bonding

Bonding (also known as “Ethernet bonding”) is a computer networking arrangement in which two or more network interfaces on a host computer are combined for redundancy or increased throughput.
mode=0 (Balance-rr) – This mode provides load balancing and fault tolerance.
mode=1 (active-backup) – This mode provides fault tolerance.
mode=2 (balance-xor) – This mode provides load balancing and fault tolerance.
mode=3 (broadcast) – This mode provides fault tolerance.
mode=4 (802.3ad) – This mode provides load balancing and fault tolerance.
mode=5 (balance-tlb) – Prerequisite: Ethtool support in the base drivers for retrieving the speed of each slave.
mode=6 (Balance-alb) – Prerequisite: Ethtool support in the base drivers for retrieving the speed of each slave.

Note: Always append extra configuration in case of a rollback.

Configuring  Bonding

# cd /etc/sysconfig/network-scripts/

# vi ifcfg-bond0

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DEVICE=bond0 USERCTL=no BOOTPROTO=none ONBOOT=yes IPADDR=10.0.0.10 NETMASK=255.255.0.0 NETWORK=10.0.0.0   TYPE=Unknown IPV6INIT=no

# vi ifcfg-eth0

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DEVICE=eth0 BOOTPROTO=none ONBOOT=yes MASTER=bond0 SLAVE=yes USERCTL=no

# vi ifcfg-eth1

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DEVICE=eth1 BOOTPROTO=none ONBOOT=yes MASTER=bond0 SLAVE=yes USERCTL=no

# vi ifcfg-eth2

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DEVICE=eth2 BOOTPROTO=none ONBOOT=yes MASTER=bond0 SLAVE=yes USERCTL=no

Due to the fact that /etc/modprobe.conf has been deprecated in RedHat / CentOS 6, the process of bonding network interfaces has changed a bit.
Now instead of defining your bond in your /etc/modprobe.conf, you define it in /etc/modprobe.d/bonding.conf

# vi /etc/modprobe.d/bonding.conf

We’ll be using mode=6 (Balance-alb)
Append the following onto the end out your modprobe config file

1 2	alias bond0 bonding options bond0 mode=6 miimon=100

# servive network restart

P2P P2V V2V V2P or Clone RedHat /CentOS /Fedora /Ubuntu

Using dd Clone Server or P2P P2V V2V V2P

 Exactly same hardware.

 Different hardware.
 Virtual  Machian

In my case 2 HP ProLiant DL385, one server is year old and seen come to DC is it on from there we have clone using following.

HP ProLiant DL385 = studyhat.com which is in live for production.
HP ProLiant DL385 = new brought to DC we want to create clone of studyhat.com
We have created on XEN virtualization one clone of HP ProLiant DL385  

* Boot with Live CD's new server where you want clone.

* Give IP Address to eth0 .

* Ping to the server from where you want to clone.

* dd if=/dev/sda | ssh root@ipaddress "dd of=/dev/sdb"

* ssh <ipaddress of running server> 'dd if=/dev/sda' | dd of=/dev/sda

* ssh <ipaddress of running server> 'dd if=/dev/sdb' | dd of=/dev/sdb 

* # dd if=/dev/sda | ssh root@xxx.xxx.xxx.xxx (target ip address )'dd of=/dev/sda'

*#dd if=/dev/sda |gzip -c --fast| ssh root@target ip address 'gzip -d | dd of=/dev/sda'

* Once you get # <console> 

* #vi /etc/sysconfig/network

* #vi /etc/hosts /

* #vi /etc/sysconfig/network-scripts/ifcfg-bond0

*  #vi /etc/sysconfig/network-scripts/ifcfg-eth0

*    * #vi /etc/resolv.conf

*    * # reboot

 

Linux Directory Structure

/bin - This directory contains most of your non-privileged system commands such as ls, mkdir, rm, etc.

/boot - Contains the systems boot image, bootloader, and the kernel

/dev - Symbolic links to system devices such as optical and removable drives

/etc - Contains all system configuration files and most configurations for installed packages

/home - Contains a directory for each user and contains profile information

/lib - Contains dynamic libraries and modules for the Linux system and installed packages

/media - Contains mount points for optical drives and removable media

/mnt - Used as a location for mounted drives and shares

/opt - Contains user installed packages and custom software not handled by the system or package manager

/proc - An interface between the kernel and the system, useful for diagnostics and system information

/root - The root superuser's home directory

/sbin - Contains privileged commands that are usually run as superuser (root/sudo)

/sys - An interface between the kernel and the system, used for modifying system settings

/tmp - A location for temporary files such as sessions on a web server

/usr - Contains most installed packages that are not part of the system, user installed programs

/usr/bin - Contains commands related to user installed packages in /usr

/usr/sbin - Contains privileged commands related to user installed packages in /usr

/var - Contains files that change often or accessed frequently

/var/log - Contains all system logs and most logs generated by installed packages

Linux NAT

If you are running a recent 2.6 Linux Kernel this four step process should work for you. This has been specifically tested on Fedora Core 3, 4, 5, and 6, but should work on any modern Linux distribution. All of these commands must be executed as the root user. First you need to tell your kernel that you want to allow IP forwarding.

echo 1 > /proc/sys/net/ipv4/ip_forward

Then you'll need to configure iptables to forward the packets from your internal network, on /dev/eth1, to your external network on /dev/eth0. You do this will the following commands:

/sbin/iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
/sbin/iptables -A FORWARD -i eth0 -o eth1 -m state --state RELATED,ESTABLISHED -j ACCEPT
/sbin/iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT

You should now be NATing. You can test this by pinging an external address from one of your internal hosts. The last step is to ensure that this setup survives over a reboot. Obviously you should only do these last two steps if your test is a success.