Python Microservices Development

Performance metrics

When a microservice eats 100% of server memory, bad things will happen. Some Linux distributions will just kill the greedy process using the infamous out-of-memory killer (oomkiller).

Using too much RAM can happen for several reasons:

• The microservice has a memory leak and steadily grows, sometimes at a very fast pace. It's very common in Python C extensions to forget to dereference an object and leak it on every call.
• The code uses memory without care. For example, a dictionary that's used as an ad hoc memory cache can grow indefinitely over the days unless there's an upper limit by design.
• There's simply not enough memory allocated to the service--the server is getting too many requests or is too weak for the job.