Stupid simple scripts for automaticaly scale applications hosted in a Cloudfoundry PaaS

Requiremts

• Ruby 1.9.3 +
• Apache Benchmark (http://httpd.apache.org/docs/2.2/programs/ab.html)
• Some CF based PaaS public/private provider with full access to the Cloud Controller API

Set up

Clone the repo

git clone <this repo CLONE URL >
cd cf-auto-scaling
bundle

Set up credentials and application details

cp config/config.yml.template config/config.yml

Replace values in config.yml to fit your context.

Also you can use following environment variables to configure autoscaler: CF_API, CF_USERNAME, CF_PASSWORD, CF_ORGANIZATION, CF_SPACE, CF_APPLICATION

Push demo app

I've created a simple sinatra app that generate secure random number which require CPU (I am very new at this. Sorry for my ignorance)

You need to be targeted and logged in into a CF PaaS

cd cd sinatra-test-app/
cf push

Auto-Scaling script

Just run

bundle exec ./bin/auto_scale.rb

This script runs forever. Just CTR + C it when you are done

Throw load to the app

Lets make 5000 requests with 20 requests at a time

ab -n 5000 -c 20 http://sinatra-manu.<paas app domain>/

Whatch it working

First output

Cloudfoundry target: https://api.....
Authenticating with user: <your username defined in config/config.yml>
Fetching first space...
Got space: development

Fetching first app from space development ...
Got app: sinatra-manu (sinatra-manu....)

CPU threshold: 70%
------------------
App sinatra-manu stats:
-- Instances: 1
-- AVG CPU load: 0.00 %
-- AVG Memory: 25.91 MB

When requests are hitting harder, lets suppose your instane is running out of CPU power, you'll get something like this

App sinatra-manu stats:
-- Instances: 1
-- AVG CPU load: 100.00 %
-- AVG Memory: 25.91 MB

------------> AVG CPU Load went over threshold (70 %), scaling app by 1 instance
Scaling successful. Lets wait a moment for the new instance to start..

Update successful
App sinatra-manu stats:
-- Instances: 2
-- AVG CPU load: 50.00 %
-- AVG Memory: 25.90 MB

------------> AVG CPU Load went over threshold (70 %), scaling app by 1 instance
Scaling successful. Lets wait a moment for the new instance to start..

App sinatra-manu stats:
-- Instances: 3
-- AVG CPU load: 33.00 %
-- AVG Memory: 24.32 MB

App sinatra-manu stats:
-- Instances: 3
-- AVG CPU load: 33.00 %
-- AVG Memory: 25.79 MB


App sinatra-manu stats:
-- Instances: 3
-- AVG CPU load: 0.00 %
-- AVG Memory: 25.61 MB

Deploy autoscaler as an application to Cloud Foundry

Aditionaly you can run autoscaler application within Cloud Foundry. In order to do it just copy manifest.yml.template to manifest.yml, fill in necessary info and run cf push. It's easy!

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You are welcome to contribute via pull request.