1. Commonsense Linux Sysad for
Scaling Webapps
M.K.Pai
madhavprasad.pai@gmail.com

2. Agenda
● Availability
Security
●
● Deployment
● Monitoring
● Q&A

3. The cloud means
● Outsourcing server procurement and deployment

4. The cloud means
● Outsourcing server procurement and deployment
● On-demand virtualization

5. The cloud means
● Outsourcing server procurement and deployment
● On-demand virtualization
● Server proliferation ? Hopefully not !

6. What is scalability ?
The ability to process more work gracefully

7. How scalable is “unavailable” ?
Do you need to be on multiple clouds ?

8. How scalable is “unavailable” ?
Is DNS a part of the application ?
Should DNS be in the cloud ?

9. How scalable is “insecure” ?
● Defense in depth
● Access controls and firewalls
● Selinux
● Incident Response ?

10. Is the workplace in the cloud ?
● The alphabet soup:
IPSec, IPv6, PKI, TLS, VPN
● Kerberos ?

11. Deployments
● Common share ro over Kerberized nfs
● Or software management tools ?
● Replication
● Two phase commits
● Choice of message queue solutions

12. Tuning the Linux vm in the cloud
● Avoid disk IO
● Use the noop scheduler
● Use a kernel > 2.6.38 for memory management
● cgroups

13. Monitoring
● Sar still rocks
● Systemtap has hooks for php/python/java

14. Key takeaways
● Scaling is a holistic exercise
● The cloud hasn't changed much
● Commonsense