Clustering legacy websites with keepalived and haproxy.

We had a legacy website we could not get rid of, it was very stable on debian lenny 5.0.  After much grief I managed to compile and RPM version of php 5.2 which it needed --- not php 5.3, not 5. anything, it HAS to be 5.2.  Ok so, finally I was able to get it running in CentOS 6.

I also clustered the filesystem using gfs2.  I did not remember until  yesterday that I configured this server to also server SMB share.  It was like 5 years ago and users are still on it!  So I also had to use clustered samba (CTDB).  Finally I got it working again.

I was able to get this thing clustered using keepalived cookie tricks--basically haproxy tricks users browser into connecting to only one and the same backend webserver, but different users connect to different backends.  Thats basically Active/Active already.  I just finished and tested this right now even on a holiday weekend.

So what we have now is

---ext ip ----- frontserver1/frontserver2 ------- webserver1/webserver2

The webservers themselvfes also host mysql.  Basically a four-pack HA setup.  I tested rebooting nodes and the websites continue to work.

Its good unfortunately a lot of IP addresses were allocated.  about 7 instead of just one .  But everythings virtual so I guess thats ok.

JondZ