Clarification on /proc/<pid>/cgroup for Azure Container Instances and Azure Container Apps

Question

For Azure Container Instances, the format of /proc/<pid>/cgroup entry for pid appears to be <pid>:pids:/containers/<ID>

For Azure Container Apps, it appears to be

<pid>:pids:/default/<ID>

Can someone confirm whether the /proc/<pid>/cgroup line for Azure Container Instances always contains the keyword containers, and the line for Azure Container Apps always contains the keyword default?

We plan to add parsing logic based on these keywords.

Answer 1

Hi , Welcome to MS Q&A

Please check below points for answers in detail

• The /proc/<pid>/cgroup file in Azure Container Instances (ACI) is used to display the control groups hierarchy for a specific process ID (PID). Control groups (cgroups) are used to limit, account for, and isolate resource usage (CPU, memory, and I/O) of a collection of processes.

In ACI, the container group is the top-level resource, and all containers in a container group share a lifecycle, resources, local network, and storage volumes. Therefore, the /proc/<pid>/cgroup file for a specific PID in ACI would display the cgroups hierarchy for that specific container within the container group.For more information, you can refer to the following resources:

Container groups in Azure Container InstancesTroubleshoot common issues in Azure Container Instances

• The /proc/<pid>/cgroup line for Azure Container Apps always contains the keyword 'default' because Azure Container Apps uses the default cgroup configuration for container isolation. This means that each container is isolated in its own cgroup, and all containers are grouped under the 'default' cgroup. For more information, you can refer to the following resource:https://learn.microsoft.com/en-us/azure/container-apps/java-overview?wt.mc_id=knwlserapi_inproduct_azportal#troubleshooting

Kindly accept answer if it helps

Thanks

Deepanshu