high availability server apps
DESCRIPTION
Talk we gave Benoit and I at the OSDC/OWF in Paris.TRANSCRIPT
High AvailabilityServer apps
Tarek Ziade & Benoît Chesneau
1Monday, October 3, 2011
• The C10K problem
• “It's time for web servers to handle ten thousand clients simultaneously, don't you think? After all, the web is a big place now. “
• http://www.kegel.com/c10k.html
2Monday, October 3, 2011
More & more hits3Monday, October 3, 2011
More & more media4Monday, October 3, 2011
• 1993 - 1998 - CGI (and java applets...)
• Apache & Prefork - simple
• Multiprocessing - threads vs events
A bit of history5Monday, October 3, 2011
6Monday, October 3, 2011
• 1993 - 1998 - CGI (and java applets...)
• Apache & Prefork - simple
• Multiprocessing - threads vs events
A bit of history7Monday, October 3, 2011
Clients
Socket Port 80
Worker
Application Minitel8Monday, October 3, 2011
Waiting...9Monday, October 3, 2011
Moar10Monday, October 3, 2011
Fork11Monday, October 3, 2011
Fork12Monday, October 3, 2011
Fork13Monday, October 3, 2011
Fork14Monday, October 3, 2011
Multiprocessing15Monday, October 3, 2011
multiprocessing16Monday, October 3, 2011
• Threads or Events ?
• Apache, Nginx, Node.js, .... (Erlang)
17Monday, October 3, 2011
• MPM Prefork
• MPM Worker (hybride prefork + threads par requêtes)
$ ab -n 1000000 -c 250 http://127.0.0.1/$ ps ax|grep apache2|wc -l152
$ ps ax|grep apache2|wc -l5
18Monday, October 3, 2011
• 1 master process, several workers
• Prefork
• Accepts several connections per worker
• Events
19Monday, October 3, 2011
• 1 single thread
• 1 event loop (READ/WRITE)
• Context switching
Event Loop20Monday, October 3, 2011
• Nginx VS Apache
• http://blog.webfaction.com/a-little-holiday-present
21Monday, October 3, 2011
Nginx versus Apache (with the worker-MPM) for serving a small static file:
22Monday, October 3, 2011
Memory usage
23Monday, October 3, 2011
Choicehttp://www.ostinelli.net/a-comparison-between-misultin-mochiweb-cowboy-nodejs-and-tornadoweb/
24Monday, October 3, 2011
• WSGI (PEP 3333)
• Prefork - shared socket
• async & sync workers (gevent, eventlet, tornado, ...)
• Easy to use in Django, Paster, ...
25Monday, October 3, 2011
Fork26Monday, October 3, 2011
Fork + async27Monday, October 3, 2011
• HTTP Stream
• Restartless upgrades ala Nginx
• Simple CLI:
$ gunicorn -w 3 test:app
• greins (https://github.com/meebo/greins)
28Monday, October 3, 2011
29Monday, October 3, 2011
30Monday, October 3, 2011
asynchronous or
synchronous
31Monday, October 3, 2011
• bandwidth-bound & CPU-bound apps
• Fast operations required
• Needs a way to hold incoming connections (cf nginx + gunicorn sync)
synchronous32Monday, October 3, 2011
• websocket, longpolling
• apps with long, blocking calls
• streaming
• slow clients
• slowloris & other DoS
asynchronous33Monday, October 3, 2011
gevent & eventlet
• Network libraries
• synchronous API
• monkey patch
• co-routines
• Code is always running async
gevent & eventlet34Monday, October 3, 2011
twisted
• asynchronous library
• Events & callbacks
• Twisted server == single event loop
twisted35Monday, October 3, 2011
36Monday, October 3, 2011
• message passing
• greenlets
• py.py --withmod-_stackless
http://www.grant-olson.net/python/intro-to-stackless-python
stackless37Monday, October 3, 2011
• ulimit is your friend
• somaxcon
• ...
Tuning38Monday, October 3, 2011
39Monday, October 3, 2011
40Monday, October 3, 2011
Firefox Sync
41Monday, October 3, 2011
42Monday, October 3, 2011
• 10 frontends web
• +123 mysql (percona)
• 6 Open Ldap servers (2 masters, 4 slaves)
• ~1.5 M active users
• ~4 M registered users
• ~800 RPS for the storage
• CPU: 20% !!! ETooMuch
43Monday, October 3, 2011
• silverlining (http://cloudsilverlining.org/) by @ianb
• kraftwerk (http://kraftwerk-wsgi.org)
Deploy44Monday, October 3, 2011
• libcloud (http://libcloud.apache.org/): deploy on the “clouds”
• juju (https://juju.ubuntu.com/) : ubuntu cloud (openstack + ensemble or ec2)
Deploy45Monday, October 3, 2011
• Apache Bench (ab)
• httperf
• Apache Jmeter
• Grinder
• Funkload
Bench46Monday, October 3, 2011
Funkload47Monday, October 3, 2011
Funkload48Monday, October 3, 2011
Thanks !
• @benoitc
• @tarek_ziade
Moar ???49Monday, October 3, 2011