如何限制Edge设备上edgeAgent的内存

Question

I have found out from Azure team that the memory limit for Edge modules including edgeHub can be controlled by specifying createOptions -> HostConfig -> Memory . How to control memory limit for edgeAgent Docker container as it is created by edgeAgent ? Is this documented? Currently here it shows as 1.88GB on a 2GB VM.

Below is an extract from docker stats

fd66aaa4dbe1        edgeAgent                 0.01%               40.59MiB / 1.885GiB   2.10%               2.18MB / 1.13MB     55.6MB / 705kB      15

Answer 1

Setting the memory limit is not specific to the edgeHub module but it is the same for any other docker module used with IotEdge. You can add the Memory setting to the HostConfig section in the createOptions of any module.

For the edgeAgent the deployment setting would look like this:

"systemModules": {
          "edgeAgent": {
            "type": "docker",
            "settings": {
              "image": "mcr.microsoft.com/azureiotedge-agent:1.0",
              "createOptions": "{\"HostConfig\":{\"Memory\":536870912}}"
            }
          },
          "edgeHub": {
          ...
          }
        }

With this do a new deployment.

For the changes to take affect on your machine you have to remove the edgeAgent module so it will create a new one according to your changed deployment rules. You can do so with the following command:

sudo docker rmi mcr.microsoft.com/azureiotedge-agent:1.0 -f

After that restart the iotEdge Deamon with

sudo systemctl restart iotedge

After that the memory will be limited for the edgeAgent module.

Note: If you want to limit memory on a Raspberry Pi, be aware that memory limit support is turned off by default. You can find a HowTo for enabling it here: https://blog.raveland.org/post/docker_raspian/