Set Up A Simple High-Availability Web Server For A Small Company Using Debian Lenny

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Submitted by rax (Contact Author) (Forums) on Fri, 2009-09-18 16:34. :: Debian

Set Up A Simple High-Availability Web Server For A Small Company Using Debian Lenny

This tutorial was written for the Debian Lenny distribution and supposes that the user has knowledge about what load balancing is and some basic skills of Linux, our two load balancers consist out of 2 machines that monitor each other [heartbeat], if the master stops responding the secondary one [Backup] will take the master role [Backup -> Master].

For this setup, we will need 3 IP addresses, 2 for each node and one virtual IP address that will be used by the master node (master node will catch this IP). At the end we will install Apache as our web server.

 

1. Enable IPVS On Both Nodes

IPVS (IP Virtual Server):

lb01/lb02

echo ip_vs_dh >> /etc/modules
echo ip_vs_ftp >> /etc/modules
echo ip_vs >> /etc/modules
echo ip_vs_lblc >> /etc/modules
echo ip_vs_lblcr >> /etc/modules
echo ip_vs_lc >> /etc/modules
echo ip_vs_nq >> /etc/modules
echo ip_vs_rr >> /etc/modules
echo ip_vs_sed >> /etc/modules
echo ip_vs_sh >> /etc/modules
echo ip_vs_wlc >> /etc/modules
echo ip_vs_wrr >> /etc/modules

modprobe ip_vs_dh
modprobe ip_vs_ftp
modprobe ip_vs
modprobe ip_vs_lblc
modprobe ip_vs_lblcr
modprobe ip_vs_lc
modprobe ip_vs_nq
modprobe ip_vs_rr
modprobe ip_vs_sed
modprobe ip_vs_sh
modprobe ip_vs_wlc
modprobe ip_vs_wrr

If you get errors, it means that you are not using debian lenny or you have recompiled lenny original kernel . Kernel must be compiled with IPVS.

 

2. Install Ultra Monkey On The Load Balancers

To install Ultra Monkey, edit /etc/apt/sources.list and add these two lines (don't remove other repositories):

lb01/lb02

pico /etc/apt/sources.list

deb http://www.ultramonkey.org/download/latest/ sarge main
deb-src http://www.ultramonkey.org/download/latest sarge main

Next we do this:

lb01/lb02

apt-get update

If you get this error...

W: GPG error: http://www.ultramonkey.org sarge Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 03C0023E05410E97
W: You may want to run apt-get update to correct these problems

... there are few workarounds, but here goes the most trusted one on the job!

Create a file named: key.asc and use the following code:

pico /home/key.asc

-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: SKS 1.1.0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wuj/SJJiKUhtiZQ26NiawQNDUcxUPgb8oYgGyZRL1GcGWs45RADiEUNSHifqm+CcRSkQFXex
GFHDDnHKFFnyVHKaWrwG6Ty9TFlx7+jo8gwDyphBLV0nsTYQcJvjAAMFCACSMCA/aewrLvVo
C63o90CKgftkpwt53lp/1vqBvRzuZlCTLQ5ijbA2Pn/9oqPfWUqeIObr2YCRlpwnw5jfOKah
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CgkQA8ACPgVBDpfxKACeIfmJdm0wyb6FNyfP9/yYlSak1T8AoJjH/Pc+Uwq5T0kUEdcurSEm
MZd1
=5NNR
-----END PGP PUBLIC KEY BLOCK-----

Run the following command to fetch the missing public key...

gpg --import /home/key.asc

... and add the key to the keyring...

apt-key add /root/.gnupg/pubring.gpg

... and issue..

apt-key update

... then...

apt-get update

Back to the tutorial. Install Ultra Monkey:

lb01/lb02

apt-get install ultramonkey

dpkg-reconfigure ipvsadm

Answer as follows:

Do you want to automatically load IPVS rules on boot?
No

Select a daemon method.
None

 

3. Enable Packet Forwarding On The Load Balancers

lb01/lb02

pico /etc/sysctl.conf

Uncomment the following line so that the load balancers are able to route traffic:

# Uncomment the next line to enable packet forwarding for IPv4
net.ipv4.ip_forward=1

After that run this:

lb01/lb02

sysctl -p


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