[Core] SkyPilot conda shadows pre-configured environment in docker containers

[romilbhardwaj]

When using docker containers as the runtime environment (image_id: docker:...), SkyPilot's installed conda gets activated by default during run, setup and when you ssh. This trips up users, who may have configured their envs without conda:

Examples include nemo and vllm images:

sky launch --image-id docker:vllm/vllm-openai:latest

# python -m vllm.entrypoints.openai.api_server does not work without conda deactivate

Our vLLM yaml also does the same:

skypilot/llm/vllm/serve-openai-api-docker.yaml

Line 12 in 38b101d

conda deactivate

More quotes from users:

vllm image doesn’t work super well as a base image for skypilot. Doesn’t seem to have anything useful installed
...
explains why my past attempts to use this approach all failed

Another user runs on k8s with custom image. He is forced to runs conda deactivate in the YAMLs he shared with us.

We should probably not activate conda by default when docker image is specified.

[romilbhardwaj]

Related to #3697.