Bonding interfaces in Linux

Bonding interfaces provides lb/ft to a network connection. So, if you have a lot of nics and a managed switch (supporting trunking), bonding will be a very good option!

First, create a bond interface file:

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

DEVICE=bond0

IPADDR=x.x.x.x

NETWORK=x.x.x.x

NETMASK=x.x.x.x

USERCTL=no

BOOTPROTO=none

ONBOOT=yes

Next, set the first interface in the bond:

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

DEVICE=eth0

USERCTL=no

ONBOOT=yes

MASTER=bond0

SLAVE=yes

BOOTPROTO=none

Then, the second interface:

# vi /etc/sysconfig/network-scripts/ifcfg-eth1

DEVICE=eth1

USERCTL=no

ONBOOT=yes

MASTER=bond0

SLAVE=yes

BOOTPROTO=none

Add the bonding module to the modules configuration:

# vi /etc/modprobe.conf

alias bond0 bonding

options bond0 mode=0  miimon=100

Mode 0 for fault tolerance, mode 1 for load balance.

To see a full list of the bonding available modes, go to the official Red Hat KB article here.

Check the bonding module:

# modprobe bonding

Restart the network service:

# service network restart

Check the status of the bond:

# less /proc/net/bonding/bond0

Bonding Mode: load balancing (round-robin)

MII Status: up

MII Polling Interval (ms): 0

Up Delay (ms): 0

Down Delay (ms): 0

Slave Interface: eth0

MII Status: up

Link Failure Count: 0

Permanent HW addr: 00:0c:29:c6:be:59

Slave Interface: eth1

MII Status: up

Link Failure Count: 0

Permanent HW addr: 00:0c:29:c6:be:63

Thats all... always remember to check /proc/net/bonding/bond0 for link failures.

Settings for nsclient (Nagios agent for Windows)

It's not a hard task, but sometimes i forget it...

1.-Install the nsclient agent as service:
unzip the agent in c:\nsclient. Don't use the msi installer!
edit nsc.ini and uncomment the following lines:

[modules]
FileLogger.dll
CheckSystem.dll
CheckDisk.dll
NSClientListener.dll
NRPEListener.dll
SysTray.dll
CheckEventLog.dll
CheckHelpers.dll

Don't uncomment the CheckWMI.dll

[settings]
allowed_hosts=
use_file=1

[NSClient]
port=12489

Save the nsc.ini file and open a command prompt. Go to c:\nsclient and execute

C:\nsclient>"NSClient++.exe" /install
Service NSClientpp installed...
l NSClient++.cpp(224) Service installed!

Next, install the System Tray icon:

C:\nsclient>"NSClient++.exe" SysTray -install

Now, go to Services and allow the nsclient service to interact with the desktop (to allow the system tray icon)

Start the service from the service manager.