Docker run -m没有设置限制（JVM占用了xms和xmx的整个主机大小）

Question

我有一台具有16GB RAM的服务器。 我正在尝试通过运行来设置容器的内存限制

docker run -it -m 500M <image-name>

在docker stats上，它显示该容器的内存限制为500MB。 但是当我尝试去做

docker exec -it <containerID> /bin/sh

并做一个“顶部”，它显示可用内存为16GB。

不应将其设置为500MB吗？

我需要500 MB的主要原因是我在每个容器中都运行了Java应用程序。 默认情况下，JVM将16gb / 64作为Xms，将4gb作为Xmx。 :(

Answer 1

我认为本文将帮助您了解为什么free和top在容器内无法正常工作。

Most of the Linux tools providing system resource metrics were created before 
cgroups even existed (e.g.: free and top, both from procps). They usually read 
memory metrics from the proc filesystem: /proc/meminfo, /proc/vmstat, 
/proc/PID/smaps and others.

Unfortunately /proc/meminfo, /proc/vmstat and friends are not containerized. 
Meaning that they are not cgroup-aware. They will always display memory 
numbers from the host system (physical or virtual machine) as a whole, which 
is useless for modern Linux containers

This causes a lot of confusion for users of Linux containers. Why does free 
say there is 32GB free memory, when the container only allows 512MB to be 
used?

https://fabiokung.com/2014/03/13/memory-inside-linux-containers/