use 5 servers to build a company web site website build exercise

1. 5 servers to build
website
A website building exercise
chuenlye leo
nova.leo@gmail.com

2. assignment
use 5 servers to build one company
website:
● automation repetitive admin tasks
● make it fully operational as "production"
● complete for operation side and
documentation as well

3. My works
some assumptions on this website:
● site purpose: a typical company website
for company introduction, market
brochure, information dissemination ,
etc.
● scale: not very big like popular social
community site, but should be flexible to

4. from the technical point of view
● read-intensive, not write-intensive
● redundancy/availability: it is a must
● scalability: better to let it be high
scalable
● performance: not very strict, but no
single point of contention is good.
● automation: it is a must in the cloud
times

5. Idea Design
● shared nothing architecture
● no single point of failure
● automate everything

6. implementation

7. 5 servers at the beginning
one LB server
two application server
two db server(mysql replication,
master/slave)

8. issues
one LB server:
single point of failure.
multiple LB servers + shared IP can fix this
problem.

9. issues
Application servers:
No single point of file system is used?
session problem?
store sessions in a memcached cluster, but
seems not easy?

10. issues
DB servers:
this site is considered as read-intensive,
so mysql replication can be considered to
be OK.
one write db server and multiple read-only
db servers to distribute read loads.
No need partitioning/sharding and no-sql.

11. details
Load Balancer with apache
soft lb alternatives:
● HAProxy
● Varnish
● Squid
● nginx
● …...

12. details
website template
morph use wordpress,
this exercise use drupal.

13. scale: phased, incremental
approach
personally, scale vertically
(CPU/MEM/IO/NW) is not prefered.
scale horizontally for application servers
scale horizontally(to some extent) for
mysql servers

14. automation
❖ automation of installation/configuration
❖ auto-scaling:
● half-auto by hand with
chef/puppet/ansible, etc
● full-auto with auto-scaling system, like
AWS auto-scaling/Scalr/RightScale/DIY

15. automation details
$ knife role list
lb-apache # for LB sever
deploy-drupal # for app server
mysql-master # for master
mysql-slave # for slave

16. automation details
we can :
● compose multiple roles for one server
e.g: all-in-one 1 server system for dev/test
● create multiple servers with the same
role in production environment for
scalability.

17. automation details
LB server:
use chef search to get all balancer
members(app servers) automatically.
members = search(:node, "role:deploy-drupal*")
<% @members.sort_by{|i| i['ipaddress'] }.each do |member| %>
BalancerMember http://<%= member['ipaddress'] %>:80
<% end %>
chef-client can be used as a daemon to update
automatically.

18. Run chef from web UI
● for people who don't use chef
● simple web demo can be extended to
one-click deploy system.
Demo site: http://lb-server/runchef

19. how to use this demo site
please see operations guide.
Thanks!