Non-heap memory leak in node:10.15.3-alpine, node:10.16.0-alpine

[mgartner]

Copied from https://github.com/nodejs/docker-node/issues/1082

We've witnessed a consistent memory leak in 2 versions of the node alpine Docker images: node:10.15.3-alpine and node:10.16.0-alpine. This leak may be present in other versions of the alpine images, but we know it is NOT present in node:6.11.1-alpine, node:8.16.0-alpine, node:10.15.3-jessie, and node:10.15.3-stretch.

This leak is a non-heap leak—the Node heap is not consistently growing, but the memory used by the docker container is.

Here is are some graphs demonstrating the leak across ~20 containers. The blue lines are the RSS of the docker containers and the red lines are the size of the Node heaps of the processes within each container.

node:10.15.3-alpine

node:10.16.0-alpine

node:10.15.3-stretch (no leak, for reference)