Spitogatos.gr is a leading real estate portal in Greece. This presentation describes high level architecture and the learnings of a recent migration from dedicated servers to a more scalable solution in the cloud of Amazon. Presentation was given at a meetup of AWS Usergroup Greece (AWSUGGR).

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