The document discusses strategies for scaling LAMP applications on cloud computing platforms like AWS. It recommends: 1) Moving static files to scalable services like S3 and using a CDN to distribute load. 2) Using dedicated caching systems like Memcache instead of local caches and storing sessions in Memcache or DynamoDB for scalability. 3) Scaling databases horizontally using master-slave replication or sharding across multiple availability zones for high availability and read scaling. 4) Leveraging auto-scaling and load balancing on AWS with tools like Elastic Load Balancers, CloudWatch, and scaling alarms to dynamically scale application instances based on metrics.

1. CLOUD COMPUTING &
LAMP APPLICATIONS
Gabriele Mittica
www.gabrielemittica.com - @gabrielemittica
Corley srl - www.corley.it
Cloud Conference 2013

2. LAMP & Scalability
• Applications deployed on LAMP platforms are not usually designed to be scalable
Disk
Access
MySQL Network
Traffic

3. Common scalability

4. HOW TO SCALE?

5. Scalability and High Availability

7. Static files
We can’t host static files (uploads, The goal is make our web instances
images, css…) on the web instance full dedicated to host the logic of the
application, with no relationships to
static files.
• Move static files to a dedicated
service like S3
• S3 is a scalable service that grants the
99,999999999% of file durability With AWS, you can upload files from
your instances to a S3 bucket with AWS
• We can use a CDN and create several SDK for php
subdomains as media.mywebsite.tld, (http://aws.amazon.com/sdkforphp/)
upload.mywebsite.tld, etc.

9. Cache and sessions
We need a dedicate service where host • session.save_handler =
cache and sessions, in order to make memcache
them always
• session.save_path =
• Use an hosted cache system (as "tcp://1.cache.group.doma
Memcache) instead of local ones (as in.tld:11211"
APC)
• PHP has a native handler to use
manage sessions with Memcache
• We can use a Elasicache or
DynamoDB to host both cache and
sessions

11. Database scalability
• Multi A-Z • Master / Slave (Read Replica)
When you provision a Multi-AZ DB The master database is regarded as the
Instance, Amazon RDS automatically authoritative source, and the slave
creates a primary DB instance and databases are synchronized to it.
synchronously replicates the data to a
standby instance in a different Use the master instance to write and
Availability Zone (AZ). slave ones to read data.
+ easy to manage + easy to scale
- pay double - hard to manage

12. Database scalability
• MySQL native driver?
• Available from PHP >=5.3
• Compile PHP with mysqlnd support
• --with-mysqli=mysqlnd --with-pdo=mysqlnd --with-mysql=mysqlnd
• WARN mysql extension is deprecated as of PHP 5.5.0
• Delegate to “mysqlnd_ms” the master/slave
management
• http://www.php.net/manual/en/book.mysqlnd-ms.php

13. Database scalability
{ The simple JSON configuration is divided in two main
"myapp": {
"master": { section
"master_0": {
"host": "localhost", • Master
"port": "3306"
} • Slaves
},
"slave": {
"slave_0": {
“myapp” is the hostname that we use instead the real
"host": "192.168.2.27", mysql host address.
"port": "3306"
}
} Eg.
} • mysql_connect(“myapp”, “user”, “passwd”);
} • new Mysqli(“myapp”, “user”, “passwd”);
• new PDO(“mysql:dbname=testdb;host=myapp”);

15. Load balancing
• ELB – Elastic Load Balancer
• Distributed load balancer on AWS regions (eu- When a server starts, it has to create a valid
west-1, 2, 3 you have to select in how many region environment in order to provides web pages.
you are available) Strategies?
Compile and bundle all softwares in one instance
• Watch EC2 status thanks to a ping strategy
image
• Page check every x minutes/seconds • all software becomes old very quickly and
• Turn on/off EC2 instances automatically thanks to when you have to release an update you
alarms (CloudWatch raise alarms) have to compile a new image and update - It
• Receive Alarms from CloudWatch and engage scale is a long and complex operation
operations
• You can raise CPU alarms, Network Alarms, VM status Use EC2_USER_DATA feature provided by AWS
alarms and many others in order to increase or decrease • You can run a shell script when your
the actual number of EC2 instances bootstraps. It is more flexible
• Scale strategy is not simple and you have to because you can create a skeleton (PHP +
understand how your application works libraries) and download all software runtime
• CPU is the simplest way but remember that the during the boot operation
bandwidth is limited by network interfaces and
bottlenecks can obfuscate the CPU alarm and your
application stucks in weird and strange situations.

16. Load balancing
• If you ran 10 servers execute
commands could be hard. You
can use tools to run command
on a server list
• Capistrano (Ruby)
https://github.com/capistrano/capistra
no
• Fabric (Python)
https://github.com/fabric/fabric
Use CLOTH for AWS EC2
instanceshttps://github.com/garethr/cloth

18. jMeter App
instances instances
1 billion of monthly pageviews
Average 400 concurrent connections
60 $ on the cloud

19. before after

20. More code on
http://www.slideshare.net/corleycloud/corl
ey-scalability-19163383

21. THANKYOU
http://www.corley.it