Php & cloud computing

transcript

PHP & Cloud Computing

PHPTOSTART 2013Walter Dal Mut - @walterdalmut - @corleycloud

Walter Dal Mut walter.dalmut@gmail.com @walterdalmut @corleycloud @upcloo

Whoami

• Walter Dal Mut• Startupper

• Corley S.r.l.• http://www.corley.it/

• UpCloo Ltd.• http://www.upcloo.com/

• Electronic Engineer• Polytechnic of Turin

• Social• @walterdalmut - @corleycloud - @upcloo

• Websites• walterdalmut.com – corley.it – upcloo.com

• Corley S.r.l.• Scalable CMS

• www.xitecms.it• Load and Stress tests

• www.corley.it• Consultancy

• PHP• AWS• Distributed Systems• Scalable Systems

AWS - Application Management Solutions

Why scalability

Source Jeff Barr AWS slideshare.net/…

Also daily…

Provision with fixed hardware

Thanks to Cloud Computing

Are you wasting monies?

Scalability effects on your business

• Scale capacity on demand• Turn fixed costs into variable costs• Always available• Rock-solid reliability• Cost-effective• Reduce time to market• Focus on product and core competencies

Distributed systems

Scalability != PerformanceScalability != High Availability

Scalability is the ability of a systemto handle

a growing amount of workin a capable manner

orits ability to be enlarged toaccommodate that growth

Scalable PHP environments – Initial Step

Web Instance MySQL89.30.31.32/32

Scalable PHP environments – autoscaling

Elastic Load BalancerWeb

Instance

Web Instance

Instance

Web Instance

Web Instance MySQL

Read Replica

AWS (Elastic) Load Balancer

• You can distribute incoming traffic across your web instances• When it detects unhealthy load-balanced web instances, it no longer

routes traffic to those web instances and spreads the load across the remaining healthy web instances.

• Elastic?• automatically scales its request handling capacity in response to incoming

application traffic.

Autoscaling

• Scale out web instances seamlessly and automatically when demand increases

• Replace unhealthy or unreachable instances to maintain higher availability of your applications.

• Scale dynamically based on your Cloud Watch metrics, or predictably according to a schedule that you define..

• Run on-demand or spot instances

Metrics and Autoscaling

EC2 Instance CloudWatch

Autoscaling

Scaling rules

Elastic Load Balancer

Autoscaling

Scaling rules

Alarms

EC2 Instance

Autoscaling

Scaling rules

EC2 Instance

Autoscaling

Scaling rules

Alarms

EC2 Instance

Autoscaling

Scaling rules

Scale with metrics, scheduled or both?• How to scale? It depends by your application

• Scheduled scale operations are useful when you have predictable spikes• Metrics when you have heavy spike application and you need to adjust your

infrastructure automatically• Mix previous in mixed scenarios

• Which metric use in order to scale?• It depends by your application design

• CPU heavy scale on CPU load metric• Network heavy scale on network load metric• Etc.

• Remember that applications don’t consume only CPU but also other resources

We have to discuss about:

• Session Management• If we open and close servers runtime we have to maintain PHP sessions in order

to handle user logins and other application features related to the end user session.

• Database connections• All MySQL connectors (PDO, MySQLi, [mysql_*]) handle just one connection…

No “x” RDB connection at the same time

• Software maintenance• How we can ran the same application version on all our infrastructure?

• What about logs? How we can collect VM logs in order to centralize the log management?

Session Management

• Fortunately with PHP you can use different strategies to centralize sessions

• Memcache/Memcached (AWS ElastiCache)• Redis• DynamoDB (AWS)• Etc.

• We can modify the session_handler in order to use a different storage (php.ini, your application bootstrap, etc.)

session.save_handler = memcache

session.save_path = “tcp://1.cache.group.domain.tld:11211”

MySQL – Master/Slave?

• Master/Slave is a model of communication where one device or process has unidirectional control over one or more other devices

• MySQL can scales out all your read (SELECT) operations on different slave servers.

• AWS RDS (Relational Database Service) helps you to create read replicas directly in AWS web console with a couple of clicks!

PHP Application MySQL READ Replicas

MASTER

SLAVE 1

SLAVE 2

Application

SELECT ONLY

INSERT/UPDATE/DELETE/SELECT

new PDO(“mysql:dbname=name;host=127.0.0.1”);

new mysqli(“127.0.0.1”, “user”, “pwd”, “name”);

mysql_connect(“127.0.0.1”, “user”, “pwd”, “name”);

How we can handledifferent READ only instances?

Can we send all write operationsonly on the Master instance?

MySQL Native Driver for PHP

MySQL Native Driver

• MySQL native driver?• Available from PHP >= 5.3• You have to compile your PHP with “mysqlnd” support

• --with-mysqli=mysqlnd --with-pdo=mysqlnd --with-mysql=mysqlnd

• Delegate to “mysqlnd_ms” the master/slave management• http://php.net/manual/en/book.mysqlnd.php

Create the mysqlnd_ms configuration file{ "myapp": { "master": { "master_0": { "host": "localhost", "port": "3306" } }, "slave": { "slave_0": { "host": "192.168.2.27", "port": "3306" } } }}

The simple JSON configuration is divided in two main section

• Master• Slaves

“myapp” is the hostname that we use instead the real mysql host address.

Eg.• mysql_connect(“myapp”,

“user”, “passwd”);• new Mysqli(“myapp”, “user”,

“passwd”);• new

PDO(“mysql:dbname=testdb;host=myapp”);

Maintain softwares

Instance

Maintain softwares

Instance

Web Instance

Maintain softwares

Instance

Web Instance

Maintain softwares

Web Instance

Maintain softwares

Web Instance

How we can stay fresh?

• If servers starts and stops continuously we have to find solutions to stay updated also on software

• When a server starts, it has to create a valid environment in order to provides web pages. Strategies?

• Compile and bundle all softwares in one instance image• It is very simple but all software becomes old very quickly and when you have to release an

update you have to compile a new image and update all load balancers configurations. It is a long and complex operation

• Use EC2_USER_DATA feature provided by AWS• You can run a shell script when your instances bootstraps. It is more flexible because you can

create a skeleton (PHP + libraries) and download all software runtime during the boot operation

• Typically you will use both in conjunction

Cool Up/Down – Inhibits alarms

Scales in action

Run commands on multiple servers

• If you ran many servers execute commands could be hard. You can use tools to run commands on a server list

• Capistrano (Ruby)• https://github.com/capistrano/capistrano

• Fabric (Python)• https://github.com/fabric/fabric• Use CLOTH for AWS EC2 instances

• https://github.com/garethr/cloth

• Chef• Puppet• Etc…

Fabric is very simple

#! /usr/bin/env python

from __future__ import with_statementfrom fabric.api import *

from fabric.contrib.console import confirm from cloth.tasks import * env.user = "root"env.directory = '/mnt/wordpress'env.key_filename = ['/home/walter/Amazon/wp-cms.pem'] @taskdef reload(): "Reload Apache configuration"

run('/etc/init.d/apache2 reload') @taskdef tail(): "Tail Apache logs"

run('tail /var/log/syslog')

EC2 instances are dynamic with don’t know addresses, for that reason we can use tagging system to execute commands on a group of instances

fab nodes:"^production.*" tail

Execute the “tail” command on all instances with a name that starts with “production.”

Eg.• production.web-1• production.log• production.mongodb

Centralize all logs

• We create and destroy instances thanks to alarms but when we close an instance we lose immediately all instance/application logs

• How we can manage logs?• The simplest way is to use Rsyslog clusters

• Rsyslog is an opensource software that forwarding log messages in an IP network

• Rsyslog implement the basic syslog protol• That means that we can configure apache logs to “syslog” instead using

normal text files.• In this way we can collect all logs in one group of VM and work on these files

later thanks to other technologies

Log management

• Collecting logs is not the latest operation because you have to analyse and reduce information• Move logs to S3 bucket – Time based• Analyze logs with Hadoop

• Map Reduce on the cloud with Elastic Map Reduce service (EMR)• Use script languages on top of Hadoop in order to simply the log analysis

• HIVE – Data Warehouse infrastructure (data summarization)• Pig – High level platform for creating MapReduce program

Cloud Conference 2013 – 18 April

• www.cloudconf.it• @_CloudConf_• https://www.facebook.com/pages/Cloud-Conf-Italia/140265592804313?ref=hl

• Data analysis• Hadoop – MapReduce Framework• Apache Pig – MapReduce Scripting Language for Hadoop• Apache Hive – Data Warehouse System for Hadoop

PUG User Coupon Code:

pug-user

Thanks for listening

Any questions?

Php & cloud computing

Documents