HALB 0.1.5

Haproxy and Keepalived base multiple HA on same server

HALB
===========

HALB is the wrapper script to install/setup/manage multiple haproxy configuration on the same server. Along with the Keepalived for easy failover.

Dependencies
===========
Make sure you install the keepalived and haproxy.

> In redhat/centos systems you can
> install them using

yum install -y keepalived
yum install -y heartbeat

Installation
============
You can install HALB using the pip/setuptools or install from tar.gz

pip install HALB
python setup.py install

This will install following files on your system

- /usr/bin/lbtool -- The actual wrapper lbtool script which you will be using
- /etc/HALB/halb.conf -- The Configuration file for HALB to control the data location where HALB saves/checks for data.
- /etc/HALB/DATA/* -- Actual HALB files.


The setup installs the sample configuration for you to start off present in /etc/HALB/DATA/{example.vig,real.dat,vip.dat}

Configuration
============
The Configuration file /etc/HALB/halb.conf controls follwing options

- DC - the name of the DC, optional preset to DATA
- HAPLB_HOME - HOME for your HALB installation,the actual haproxy configuration is saved under this directory
- HAPROXY -- PATH for haproxy binary
- KEEPALIVE_CONF -- Keepalived configuration file
- VIP_DEVICE -- The device name to which keepalived will bind the the VIP

The lbtool will require following four directories under HAPLB_HOME/DC

- dat - All .vig files, real.dat and
vip.dat files are stored here
- bin - copies of haproxy binary for each
individual haproxy haproxy - home for all haproxy configuration
status - status directory for all backend nodes
----------
**Adding new configs:**

-
- Create new vig file

Create new .vig file for the rotation under /etc/HALB/DATA/dat/
Ex: /etc/HALB/DATA/dat/test.vig (Replace test with the desired name)

[root@lb1 lb]# cat /etc/HALB/DATA/dat/test.vig
keepalived: vid=51
#Vip: www.test.com
www.test.com: vip=www.test.com name=www.test.com dns=www.test.com
www.test.com: port=80 vip_mode=http,https vip_maxconn=25000
www.test.com: real=tiber1:80 #is

> The keepalived vid must be unique as
> its identification for vip group in
> keepalived configuration.
>
> **Use Command to find the number of vid used in existing vig file.**

grep -ir 'keepalived: vid='/etc/HALB/DATA/dat/*.vig | awk '{print $NF}'| sort

- Add Vip info in vip.dat

Add vip information under /etc/HALB/DATA/dat/vip.dat

[root@lb1 lb]# cat /etc/HALB/DATA/dat/vip.dat
www.test.com: vip=www.test.com ip=10.0.9.214

- Add Vip info in vip.dat
Add real server information under /etc/HALB/DATA/dat/real.dat

[root@lb1 lb]# cat /etc/HALB/DATA/dat/real.dat
tiber1: status=is name=tiber1 dns=tiber1.test.colo ip=10.0.7.54

> Before adding check if the ips/servers
> are present in the vip.dat and
> real.dat. If present then there is no
> need to add. Please avoid duplicate
> entries.

----------

> Use vig name as argument to lbtool




[root@lb1 lb]# lbtool test
example> help
Valid Choices are :
exit|quit --> To exit the program
gen_conf|generate_conf --> To generate the Haproxy configuration
ha_vig --> start|stop|reload|restart|status the configuration."
gen_keep --> MASTER|BACKUP genrates the Keepalived Configuration
is --> set the server status to In serving
oos --> set the server status to Out of serving
help --> show the valid commands.


For example below steps needs to be done in order


[root@lb1 root]# lbtool test



> Name of haproxy vig as argument to lb
> script.

test > generate_conf

> Generates haproxy config file

test > gen_keep MASTER


> Generates keepalived config for the
> new rotation.if role is MASTER it the
> rotation will be active on this
> server. If BACKUP then it will receive
> traffic only when the MASTER server
> fails.



test > ha_vig start


Starts the haproxy config

test > keep_init reload

> Reloads keepalived with newly updated
> config file.

test > exit


**Adding new hosts to a config:**

Add new hosts to real.dat file.

> Before adding check if the host is
> present in the file. If yes then do
> not add. We should avoid duplicate
> entries.

Add the host to the .vig file for the rotation.

[root@lb1 lb]# lb test

> Name of haproxy vig as argument to lb
> script.

test > is tiber1

> Adds host tiber1 into rotation of
> haproxy config for test

test > generate_conf
test > ha_vig restart
test > exit

**Taking a host out of rotation:**


[root@lb1 lb]# lb test
test > oos tiber1



> Takes host tiber1 out of rotation from
> haproxy config for test.

test > generate_conf
test > ha_vig restart
test > exit


#################################################
misc -
add net.ipv4.ip_nonlocal_bind = 1 in sysctl.conf so that keepalived can bind non local ip's