What is it?
When you are using Docker Swarm as your container orchestration you often need to develop some tools to work with it by it's way. And one of the problems is how to monitor each container running inside a cluster. First thing, that I've tried was a custom Lua-script running on the Nginx/OpenResty balancer to expand whole internal cluster information including containers list, their IP addresses and special endpoints to connect to them. But then I've found a simpler and more elegant solution.
Despite this tool is named as "proof of concept", it is very well-written application and can be used even for production purposes. But I've faced one major issue with it: memory leaked too quickly. You can see how it was on the main article screenshot above. It was able to eat more then ~4 GB or RAM per day.