能否将Docker容器资源限制设置为无限制以占用服务器全部资源？

Short answer: Yes, and that's actually the default behavior unless you explicitly set resource limits for your containers. Let me break this down for you:

Default Unrestricted Behavior #

By default, Docker doesn't impose any hard limits on container resource usage:

• CPU: The container can utilize all available CPU cores on the host. If your host has 8 cores, a single container process can push CPU usage to 100% across all 8 cores if it needs to.
• Memory: There's no predefined cap on memory usage. The container will keep allocating memory until the host runs out of physical RAM (and swap space, if enabled). However, this can trigger the host's OOM (Out of Memory) killer, which might terminate the container (or other critical host processes) to free up resources.

How to Ensure/Revert to Unrestricted Resources #

For New Containers #

Simply avoid adding any resource-limiting flags when you run the container. Don't use parameters like --cpus, --memory, --memory-swap, or --cpu-shares if you want the container to have full access to host resources.

For Running Containers #

If you previously set limits and want to remove them, use the docker update command:

• Remove CPU limits:

  docker update --cpus 0 <container_name_or_id>
  

  (Setting --cpus to 0 tells Docker to lift the CPU restriction; this works in most recent Docker versions.)
• Remove memory limits:

  docker update --memory -1 <container_name_or_id>
  

  Using -1 for --memory disables the memory cap entirely.

Important Caveats #

While unrestricted access gives your container maximum resources, it's not without risks:

• A misbehaving or resource-hungry process inside the container can starve other containers or host services of resources, potentially crashing the entire system.
• Even without explicit limits, the host's kernel will still manage resources (like through the OOM killer). You can tweak the container's oom_score_adj value (via docker update --oom-score-adj <value>) to influence how likely the container is to be terminated during an OOM event—lower values mean it's less likely to be killed.

内容的提问来源于stack exchange，提问作者Jakim