Deploying Rails Applications Vivek Prahlad

Agenda Typical Rails deployment scenarios Mongrel Nginx vs. Apache vs. Lighttpd Shared vs. Virtual vs. Dedicated hosting Monitoring Rails Applications

Typical Rails deployment scenarios

Mongrel

Nginx vs. Apache vs. Lighttpd

Shared vs. Virtual vs. Dedicated hosting

Monitoring Rails Applications

Typical Rails Deployment Setup Web Server (Static Content)‏ Rails App (Mongrel)‏ Database (MySQL / PostgreSQL)‏

Lots of Static content? Web Server (Static Content)‏ Rails App (Mongrel)‏ Database )‏ (MySQL / PostgreSQL)‏ Load Balancer Cluster

Heavy database load? Web Server (Static Content)‏ Rails App (Mongrel)‏ Database (MySQL / PostgreSQL)‏ Cluster

Very dynamic application? Web Server (Static Content)‏ Rails App (Mongrel)‏ Database (MySQL / PostgreSQL)‏ Cluster

Installing the stack using Deprec cd /path/to/railsapp deprec --apply-to . --name projectname --domain www.projectname.com # edit config/deploy.rb to add svn details cap install_rails_stack cap setup cap deploy_with_migrations cap restart_apache

cd /path/to/railsapp

deprec --apply-to . --name projectname --domain www.projectname.com

# edit config/deploy.rb to add svn details

cap install_rails_stack

cap setup

cap deploy_with_migrations

cap restart_apache

Mongrel

Mongrel Pure Ruby web server for Ruby applications Supports Rails, Camping, Og + Nitro Need a cluster due to Rails threadsafety issue Significant footprint increase with Rails 1.2 Approximately 60MB / Mongrel / Mephisto instance Dash B logging for detecting memory leaks

Pure Ruby web server for Ruby applications

Supports Rails, Camping, Og + Nitro

Need a cluster due to Rails threadsafety issue

Significant footprint increase with Rails 1.2

Approximately 60MB / Mongrel / Mephisto instance

Dash B logging for detecting memory leaks

Nginx Web server from Igor Sysoev: best used as a reverse proxy Rapidly becoming preferred choice of Rails community 10MB footprint with 10,000 concurrent connections Load balancing Weighted load balancing Relatively straightforward configuration

Web server from Igor Sysoev: best used as a reverse proxy

Rapidly becoming preferred choice of Rails community

10MB footprint with 10,000 concurrent connections

Load balancing

Weighted load balancing

Relatively straightforward configuration

Nginx vs. Apache Apache: Relatively Larger footprint Thread per request Nginx: Low footprint Non blocking IO

Apache: Relatively Larger footprint

Thread per request

Nginx: Low footprint

Non blocking IO

Issues with Lighttpd Stability Memory leaks Non-trivial URL rewriting

Stability

Memory leaks

Non-trivial URL rewriting

Nginx: configuring mongrel upstream mongrel { server 127.0.0.1:10000; server 127.0.0.1:10001; } proxy_pass http://mongrel;

upstream mongrel {

server 127.0.0.1:10000;

server 127.0.0.1:10001;

}

proxy_pass http://mongrel;

Nginx: load balancing upstream backend { server backend1.example.com weight=5; server backend2.example.com:8080; server unix:/tmp/backend3; }

upstream backend {

server backend1.example.com weight=5;

server backend2.example.com:8080;

server unix:/tmp/backend3;

}

Nginx: Caveats Primary documentation in Russian (Documentation is rapidly improving, though)‏ No X-sendfile support (useful for serving large files)‏ Virtual host support poor

Primary documentation in Russian

(Documentation is rapidly improving, though)‏

No X-sendfile support (useful for serving large files)‏

Virtual host support poor

Rails Hosting Rails 1.2+ unsuitable for shared hosting Most shared hosts have published / unpublished memory caps Textdrive: 47 MB per process Dedicated hosting expensive Starts at ~ $70 per month (e.g. ServerPronto)‏

Rails 1.2+ unsuitable for shared hosting

Most shared hosts have published / unpublished memory caps

Textdrive: 47 MB per process

Dedicated hosting expensive

Starts at ~ $70 per month (e.g. ServerPronto)‏

Virtual Private Server (VPS) Hosting Fits in between Shared and Dedicated hosting Nice performance / price ratio (starts @ $20 / month)‏ Can potentially exploit superior hardware Alternatives: Xen Virtuzzo Baked in kernel level virtualization support is coming Caveat: Need to manage your own setup

Fits in between Shared and Dedicated hosting

Nice performance / price ratio (starts @ $20 / month)‏

Can potentially exploit superior hardware

Alternatives:

Xen

Virtuzzo

Baked in kernel level virtualization support is coming

Caveat: Need to manage your own setup

Advantages of VPS hosting Entire CPU available when other users are idle. Disk I/O usually faster than dedicated box (due to RAID etc.)‏ Can take advantage of SANs if required. Hosting company takes care of the VPS server Fairly easy to scale VPS setup (just add more VMs)‏

Entire CPU available when other users are idle.

Disk I/O usually faster than dedicated box (due to RAID etc.)‏

Can take advantage of SANs if required.

Hosting company takes care of the VPS server

Fairly easy to scale VPS setup (just add more VMs)‏

Monitoring Rails applications Monit (http://www.tideslash.com/monit)‏ Process monitoring tool Can monitor: HTTP server Processes Databases (MySQL and PostgreSQL)‏

Monit (http://www.tideslash.com/monit)‏

Process monitoring tool

Can monitor:

HTTP server

Processes

Databases (MySQL and PostgreSQL)‏

Cron Jobs Clear stale sessions Database maintenance Clear logs Best practice: get Cron to call out to a script Don't hardcode commands in the crontab Makes it easy to test

Clear stale sessions

Database maintenance

Clear logs

Best practice: get Cron to call out to a script

Don't hardcode commands in the crontab

Makes it easy to test

Putting it all together Can use Monit to create 'self healing' setup PostgresQL Nginx Mongrel Cron

Can use Monit to create 'self healing' setup

PostgresQL

Nginx

Mongrel

Cron

http://nginx.net/ http://railsexpress.de/blog (performance tuning)‏ http://hostingfu.com (blog on hosting)‏ http://www.slideshare.net/Georgio_1999/how-to-scale-your-web-app/ (scaling Rails)‏ Additional Information

http://nginx.net/

http://railsexpress.de/blog (performance tuning)‏

http://hostingfu.com (blog on hosting)‏

http://www.slideshare.net/Georgio_1999/how-to-scale-your-web-app/ (scaling Rails)‏

Thank You http://blog.vivekprahlad.com/