Support RStudio

[achimnol]

rocker-org/rocker#295 (comment)
RStudio's execution model requires the root account since it manages non-root users by itself -- spawning a session in non-root user (usually "rstudio").

This conflicts with non-root single-user container scenarios, like us or OpenShift.

We need to support the followings in entrypoint.sh when running RStudio images:

• Bypass gosu so that the initial RStudio daemon run as root.
• Set additional environment variables (e.g., USERID) to use our LOCAL_USER_ID value.
  • See https://github.com/rocker-org/rocker-versioned/blob/master/rstudio/userconf.sh

To customize the agent and kernel-runner behavior, let's add new kernel labels:

• ai.backend.run-as-root=1 to enable bypassing gosu. (default: disabled)
• ai.backend.envs.userid=USERID to set additional environment variables to have the agent-indicated user IDs, similarly to ai.backend.envs.corecount. (default: empty)

[amalic]

Can this be tested somewhere?

[achimnol]

@amalic Currently this issue is not on our priority yet. Also we need to figure out installing and running RStudio without root permission.

[LiNk-NY]

+1 It would be good to have this working. Thanks @achimnol

[achimnol]

Now we have a working RStudio image internally, as the issues mentioned here are resolved in their side.
But there is a usability issue related to HTTP/HTTPS redirection, because our application proxy uses HTTPS on production while the RStudio uses HTTP. In many other in-container apps such as Jupyter just work with SSL termination in Backend.AI's app proxy but RStudio requires some extra work to make it working.

Stay tuned!