Update spawn_actors API in sft v2 main.py

[daniellepintz]

spawn_actors has been removed, so updating to use as_actor API.

Also some updates to the config to make it work.

Test Plan:

python -m apps.sft_v2.main --config apps/sft_v2/llama3_8b.yaml

Output:

[3] [ForgeSFTRecipe-3/8] 2025-10-03 13:14:24 INFO 91 / 1000|Loss: 1.11570405960083
[1] [ForgeSFTRecipe-1/8] 2025-10-03 13:14:24 INFO 92 / 1000|Loss: 0.9416455030441284
[2] [ForgeSFTRecipe-2/8] 2025-10-03 13:14:24 INFO 92 / 1000|Loss: 1.0203598737716675
[3] [ForgeSFTRecipe-3/8] 2025-10-03 13:14:24 INFO 92 / 1000|Loss: 0.8977944254875183
[6] [ForgeSFTRecipe-6/8] 2025-10-03 13:14:24 INFO 92 / 1000|Loss: 1.0252584218978882

[daniellepintz]

I didn't have uv installed so this cmd didn't work. is uv necessary?

also, do we still need to do export HF_HUB_DISABLE_XET=1?

[felipemello1]

i tried 'HF_HUB_DISABLE_XET=1 about ~1 week ago and it broke. I dont think it works well with our devmachines. @joecummings do you know?

[allenwang28]

thank you!