Here are some thoughts about deploying a web service or a web application today, in 2014.

Let’s consider some expectations for the following roles:

• client : he expects the service to be reliable
• provider : he requires ease of deployment, ease of testing & maintenance

Reliability

The 3 top issues are : 

• service is not available (network) : we have to continuously check the service is available and fix the issue immediately. It can be a permanent or temporary network availability issue.
• service is slow or is returning errors : errors must be automatically detected, sysadmin must be notified immediately to take action
• service is returning incorrect result : current version of the service must have been validated by a QA team

Ease of deployment

For the service to be easy to deploy:

• deployment is done via a single deploy command
• deployment can made partially
• constant checking is done during deployment
• it’s always possible to come back
• deploy a server farm is as simple as deploying a single server

Ease of testing and no-longer-painful maintenance

Let’s imagine that:

• service execution data are collected and processed in realtime
• execution data is automatically analysed
• servers are automatically switched when necessary
• it’s easy to add new servers when service load is increasing

I’m preparing a serie of article about Mesos / Marathon. This platform, maybe, is a good opportunity to move in this direction.