It's a problem that is inherent in the way the JVM's GCs work. They never release memory even if you have low heap usage. I have a micronaut based microservice. Visual VM reports less than 30MB memory usage. Sometimes I get request spikes and it goes to 200MB. It will allocate 200MB from the OS and once the spike is gone it will hang onto the 200MB.

There is also a fixed overhead. Even if I set the heap maximum to 30MB at the cost of running out of memory during spikes the total memory used by the JVM is still around 130MB.

If you want to run 10 microservices that each do very little then you will need anywhere from 1.3GB to 3.3GB (as soon as you have one traffic spike and then never again). With go you could probably get away with just 300MB and during temporary traffic spikes your maximum will be 2.3GB at most but it is unlikely that all your microservices will spike at the same time so you will need significantly less than 2.3GB.