The document discusses the high-level architecture of Spitogatos.gr's use of Amazon Web Services (AWS) and the lessons learned during their implementation. It highlights the platform's goals to simplify property searches in Greece and presents various AWS services utilized for scalability and efficient operations. The author shares insights on challenges faced, including session management and the iterative process of continuous improvement in their cloud infrastructure.

1. Spitogatos.gr & Amazon Web Services
High level architecture & lessons learned
AWSUG GR meetup #1
16 Feb 2012
Andreas Chatzakis
co-founder / IT Director @ Spitogatos.gr

2. By David Fletcher - www.cloudtweaks.com

3. #about_us

4. Helping you find a property
Finding a property in Greece is complex, lacks transparency.
We make life easier for househunters via:
 Powerful search functionality
 Web & Mobile
 Location & Criteria
 Quality content
 Listings (we love photos)
 Articles
 mySpitogatos
 Email alerts
 Save your search
 Favorite listings & notes
 Contact the realtors
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5. Realtors love us too!
Professionals need help in those turbulent times.
We add value in multiple ways:
 Cost effective promotion & high quality leads
 Targeted channel (very)
 Leads already filtered (we ve seen the fotos!)
 Technology services for realtors
 Turnkey web site solution
 Listing synchronization web service
 B2B via Spitogatos Network (SpiN) business
network / collaboration tool for realtors
 Channel for foreign buyers via the English version
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6. Not just “αγγελίες”
Our vision is to become a one-stop-shop for all things house related
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7. #why_aws

8. The need for change
Infrastructure change dictated by our business needs
 Ongoing traffic increase
 A nice headache
 Growing Data
 S3 to the rescue
 Major new functionality
 Higher CPU & RAM requirements
 Uneven traffic pattern
 Why should I pay for this server during the night?
...and constraints
Let's not spend our time managing systems:
 AMIs? Yes thank you!
 Zero management services like ELB? √ Like
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9. #architecture

10. Your typical multi-tier web architecture
Storage Layer
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11. Tools of the trade
Currently utilizing the following AWS services
 EC2
 S3
 Property photos
 Thumbnails
 Online backups
 Elastic Load Balancer (ELB)
 CloudWatch
 Route53
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12. A bit about Scalr
Cloud management solution reduced project risks & ITOPS effort
Server Templates Config & Bootstrap
Backups Scripts DNS
Autoscaling Master Slave Recover Control
Convention over Configuration - out-of-the-box automation and scalability 12

13. Services under our radar
We will utilize additional AWS services whenever that helps us:
 Reduce in-house ITOPS overheads
 Scale capacity and performance
 Enable us to bring new added value services to the market faster
 Cloudfront
 Milan node makes it attractive vs our current CDN solution
 Simple Email Service
 ElastiCache
 SimpleDB / DynamoDB
 Sessions, Logs, Aggregate stats, Personalization etc
 EMR / HiveQL
 Xeround or Amazon RDS
 MySQL as a service
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14. #learnings

15. Not a walk in the park
From a single server to a scalable solution
 Deal with sessions
 Sticky sessions no good when autoscaling (scale downs)
 Memcache (nodes will die, sessions will be lost)
 Shared file system (maybe...) or Key-value store
 Zend Server cluster
 User uploads
 Rewrite code to utilize S3
 Or just plug in a POSIX compliant NAS solution
 Database
 Master-slave needs code changes (Replication lag)
 You thought splitting SELECTs from INSERTs/UPDATEs is sufficient?
 Individual nodes will fail – dont' take them for granted
 Holy grail: share nothing architecture
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16. Continuous improvement
It is an iterative process
 Incrementally add robbustness
 Measure and collect data (Newrelic, MONyog, sysstat...)
 Alert (Cloudwatch, monit)
 Self healing (beware of false positives)
 Fall gracefully (MRT vs MTBF)
 Optimize
 Test out different EC2 Instance Types
 Once sure, reserve them for significant savings
 Use Cloudwatch in front of S3
 Test autoscaling strategies
 Scaleup fast, scaledown slow
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17. #questions