Major Description
Stratos uses Virtual Machines and Containers for hosting platform services on different Infrastructure as a Service (IaaS) solutions. At present Puppet is used for orchestration management on Virtual Machine based systems and manages all required software in Puppet Master. Container based systems creates Docker images for each platform service by including required software in the Docker image itself.
In Virtual Machine use-case VM instances will communicate with Puppet master and execute the software installation. The same approach can be used for applying software updates.
In Docker use-case we do not use Puppet because a new container with required software can be started in few seconds. This is very efficient compared to using Puppet and installing software on demand.
The requirement of this project is to implement a core Stratos feature to propagate software updates in a live PaaS environment.
1. Puppet based solution:
- Push software updates of a cartridge to Puppet Master (might not need to automate).
- Invoke the software update process via the Stratos API for a given application.
- Stratos Manager could send a new event to trigger puppet agent in each instance to apply the updates.
2. Docker based solution
- Create a new docker image (with a new image id) for the cartridge with software updates (might not need to automate).
- Invoke the software update process via the Stratos API for a given application.
- Autoscaler can implement a new feature to bring down existing instances and create new instances with the new docker image id.
Important!
- In each scenario if updates are backward compatible, software update process should execute in phases, it should not bring down the entire cluster to apply the updates. If so the service will be unavailable for a certain time period. The idea is to apply the updates to set of members at a time.
- If the updates are not backward compatible, we could make the entire cluster unavailable at once and apply the updates.
- Member's state needs to be changed to a new state called "Updating" when applying the updates.
If there is an interest on doing this project please send a mail to imesh at apache dot org by copying Apache Dev mailing list [1]. Please refer Stratos Wiki [2] for more information on Stratos architecture and how it works.
[1] http://stratos.apache.org/community/mailing-lists.html
[2] https://cwiki.apache.org/confluence/display/STRATOS