Dynamically deploying Jenkins slaves on google compute engine for github commits

Question

This is a question of integration:

I would like to run Jenkins on Google Compute Engine. I can do this, but I will quickly break my budget if I leave an 8-core virtual machine running at all times. As a solution, I think I can leave a micro instance with a low amount of memory powered on and acting as the jenkins master running at all times. It seems that I should be able to configure github to startup a jenkins slave (with 8 cores) whenever a push is performed. How do I connect github post-commit hooks to Google Compute Engine to achieve this? A complete answer is probably asking too much, but even just pointers to the relevant documentation would be helpful.

Alternatively, how would you solve my problem?

Answer 1

You can run an AppEngine instance and use the URL it provides as the target of your GitHub on-commit web hook. This way, you won't be charged unless the instance is actually running, which may even be cheaper than running a micro instance 24x7 on Compute Engine.

You can then start/stop instances on Compute Engine or trigger actions on them from your code running on App Engine.

Here's a related question which has an answer for how to authenticate to Compute Engine from code running on AppEngine.