Hello all, I wanted to clarify this issue. Proposed solutions are based on GPT search results that seem invalid. There is no ulimits CLI parameter nor ResourceLimit in ACI API for ARM templates. I was provided with an invalid ARM template by GPT as well. Issue with GPT is that we always have to validate answers, it works by processing natural language and similarities, this probably why it's making wrong suggestions. The templates and commands probably are similar to others that are valid in other scopes. If interesting in reading more, search online why ChatGPT can't multiply small numbers correctly, this is because it bases the answer in "similar" operations and results it has read.
Now, speaking of the request, there is no way to alter ulimits in ACI. This is a security feature based in container runtime, it would be bad for a container to change these limits in the host. The runtime takes the value from host, so, this is also true even in Kubernetes (open issue since 2015: https://github.com/kubernetes/kubernetes/issues/3595). In other words, the only way to increase this limit for a container is to increase it at OS level at host. This is not available in ACI, to overcome this issue you may try AKS and change this limit in the nodes via daemonset.