Q:

Governance methodology for micro services explosion

Microservices are the trend now and most of them are developed on cloud. I have a situation where we are decomposing most of monolithic services into domain level microservices. Each problem domain having just a handful of services.
In Amazon cloud each individual services would further realize down as multiple lambda functions. As there would 100s of functions each doing specific kind of activities, deployed by individual pipeline jobs each. 
The volume of functions can potentially increase to the order of 1000s in very near future. This in comparison to 40 monolithic apps we have today. Is there any way to group, visualize, account usage metrics, cost etc?
The situation would be similar or complex than the xml hell we saw with earlier version spring framework.

A:

First off you may want to consider a framework such as Chalice if you’re moving to microservices on Lambda. This will help reduce the sprawl of services some but each case is different and all depends on where you draw your bounded contexts. 
Speaking from a similar experience to what you’re embarking on, you will want to invest heavily in a few areas. First off having a consistent logging approach is key. You’ll want to ship logs consistently to a single log aggregation service so you can easily query across all services to get metrics. CloudWatch, Sumo Logic, etc can help with this. Also use X-Ray to get more detailed insight. 
You will also want to consider adding some automation into your CI/CD pipeline to produce documentation in Swagger or something similar. This should be done in a way that the result is a searchable catalog
Of all services with all necessary documentation. My experience has involved doing this with Swagger UI and some custom HTML that gets generated and deployed on each build job. 
One last recommendation is to invest in testing. Contract testing and backwards compatibility testing is key to saving yourself from deploying breaking changes. I would also add feature toggles as another key that can go hand and hand here. 
Good luck with this effort! 

