Hi Jianjie,

Thanks for your interests with ACRN hypervisor. For VM configuration, we have several pre-defined scenarios in: https://projectacrn.github.io/latest/introduction/index.html#id3, and the most flexible scenario is ‘industry’ scenario, it runs up to 8 VMs including Service VM, so 7 Users VMs in this config.

Specific to RTVM, the max number is also limited by your target platform capability, you know to secure RT performance, RTVM may need dedicated CPU Core (2 cores for Preempt RT), and pass-through Ethernet, even disc.

1. Does acrn have any number limitation of pre-launch RTVM?

//Terry: Usually only one Pre-launch RTVM, refer to ‘Hybrid RT scenario’ in: https://projectacrn.github.io/latest/introduction/index.html#hybrid-real-time-rt-scenario  

2. Does acrn have any number limitation of post-launch RTVM?

//Terry: According to your platform CPU core number and pass-through devices, usually up to 3~4 post-RTVMs, with 8 cores and 4 ethernet ports.

3. Does acrn have any number limitation of kata-containers?

//Terry: there is one kata-container VM in ‘industry scenario’: https://projectacrn.github.io/latest/tutorials/run_kata_containers.html#run-kata-containers.

4. What’s the difference between pre-launch RTVM and Post-launch RTVM, since they both can access the hardware directly?

//Terry: From pass-through device perspective, they are all isolated in pre and post-launch RTVM.  From OS severity perspective, post-VM is launched/managed by service OS, but Pre-launch RTVM could be still alive/working even when Service OS reboot with abnormal failures.

5. Can Kata-container also be possible for real time?

//Terry: Basically Kata-container may not secure the certainty/latency of RT task, so only user level applications e.g., AI computing workload, are recommended in container.

Best & Regards

Terry