RStudio Server Controller (RSC)

This is a shell tool for conveniently launching a personal instance of the RStudio Server on a Linux machine, which then can be access in the local web browser, either locally, or remotely via SSH tunneling. RStudio is an integrated development environment (IDE) for R.

Features

User experience

It is easy to start and stop the RStudio Server, e.g. rsc start and rsc stop
Any user can run it, i.e. it requires no special privileges
It gives cut'n'paste instructions on how to access a remote RStudio Server instance via SSH tunneling through a login host
It is possible to expose the RStudio Server port on a remote machine via reverse SSH tunneling, e.g. --revtunnel=<user>@<remote-hostname>:<remote-port>
It provides convenient alternatives for setting the port where RStudio Server is hosted, e.g. --port=port4me and --port=<fix-port>.
R sessions can inherit the environment variables from the shell launching the RStudio Server, e.g. all variables by --env-pattern="^.*$" (default), or a subset as --env-pattern="^(R_.*|SLURM_.*)$"

Authentication

There are multiple options for how the RStudio Server login is authenticated. The default, --auth=auth-via-su, relies on su to authenticate using the system's authentication method. An alternative to this, is --auth=auth-via-ssh:<hostname>, which authenticates using SSH towards host <hostname>. If neither are an option, --auth=auth-via-env --random-password can be used to authenticate with a one-time, temporary password that is echoed. If --random-password is not specified for the latter, then the password is taken from environment variable RSC_PASSWORD, which is not echoed. It is also possible to use a custom authentication helper, e.g. --auth=<command-on-PATH> and --auth=<file>

Stability

A user can run at most one RStudio Server instance on a multi-host system, which minimized the number of stray instances being left behind
The RStudio Server will time out ten minutes after the most recent R session was terminated. This prevents stray RStudio Server processes being left behind
The default timeout for an idle R session is two hours
The tool attempts to be agile to different POSIX signals to shut down everything when the RStudio Server instance is terminated, e.g. by SIGINT from Ctrl-C, SIGQUIT from Ctrl-\, or a SIGUSR2 notification signal by a job scheduler

Running RStudio Server locally

To launch your personal RStudio Server instance, call:

$ rsc start
alice, your personal RStudio Server 2023.03.0+386 running R 4.3.1 is available on:

  <http://127.0.0.1:20612>

Any R session started times out after being idle for 120 minutes.
WARNING: You now have 10 minutes, until 2023-04-17 17:30:33+01:00, to connect
and log in to the RStudio Server before everything times out.

The RStudio Server can then be accessed via the web browser at http://127.0.0.1:20612. The default port number is generated by the port4me algorithm, which looks for a free port that is unique to each user and stable over time. In the case when a user's default port is already occupied, another, deterministic, user-specific port is checked, and so on, until a free port is found.

The rsc start command will run until terminated, e.g. Ctrl-C:

 $ rsc start
alice, your personal RStudio Server 2023.03.0+386 running R 4.3.1 is available on:

  <http://127.0.0.1:20612>

Any R session started times out after being idle for 120 minutes.
WARNING: You now have 10 minutes, until 2023-04-17 17:30:33+01:00, to connect
and log in to the RStudio Server before everything times out.
^C
Received a SIGINT signal
Shutting down RStudio Server ...
Shutting down RStudio Server ... done

Alternatively, the RStudio Server instance can be terminated by calling:

$ rsc stop
RStudio Server stopped

which sends a SIGTERM signal asking the different RStudio Server processes to shut down nicely. This is attempted multiple times. As a last resort, it will send SIGKILL, which kills the processes abruptly. If this command is not called from the same machine as from where rsc start was called, then it will attempt to SSH to that machine to terminate the RStudio Server.

A user can only launch one instance. Attempts to start more, will produce an informative error message, e.g.

$ rsc start
ERROR: alice, another RStudio Server session of yours is already running on
alice-notebook on this system. Call 'rsc status --full' for details on how
to reconnect. If you want to start a new instance, pleas e terminate the
existing one first by calling 'rsc stop' from that machine.

This limit applies across all machines on the same file system, which helps keep multi-tenant high-performance compute (HPC) environments tidy.

To check if another RStudio Server instance is already running, use:

$ rsc status
rserver: running (pid 29062) on current machine (alice-notebook)
listening on port 20612
rsession: not running
rserver monitor: running (pid 29101) on machine (alice-notebook)
lock file: exists (/home/alice/.config/rsc/pid.lock)

As the above error message suggests, add --full to also get information on how to reconnect to the already running RStudio Server instance.

Running RStudio Server remotely

Scenario 1: Direct access to remote machine

Assume you have a remote server that you connect to via SSH as:

[ab@local ~]$ ssh -l alice server.myuniv.org
[alice@server ~]$

If we launch rsc on the remote server, we will get:

[alice@server ~]$ rsc start
alice, your personal RStudio Server 2023.03.0+386 running R 4.3.1 is available on:

  <http://127.0.0.1:20612>

Importantly, if you are running from a remote machine without direct access
to server.myuniv.org, you need to set up SSH port forwarding first, which you
can do by running:

  ssh -L 20612:server.myuniv.org:20612 alice@server.myuniv.org

in a second terminal from you local computer.

Any R session started times out after being idle for 120 minutes.
WARNING: You now have 10 minutes, until 2023-04-17 17:30:33+01:00, to connect
and log in to the RStudio Server before everything times out.

If we follow these instructions set up a second, concurrent SSH connection to the remote server:

[ab@local ~]$ ssh -L 20612:server.myuniv.org:20612 alice@server.myuniv.org
[alice@server ~]$

we will be able to access the RStudio Server at http://127.0.0.1:20612 on our local machine. This works because port 20612 on our local machine is forwarded to port 20612 on the remote server, which is where the RStudio Server is served.

Comment: To use a separate port for the local machine in these instructions, use command-line option --localport=<port>.

Scenario 2: Indirect access to remote machine via a login host

Assume you can only access the remote server via a dedicated login host:

[ab@local ~]$ ssh -l alice login.myuniv.org
[alice@login ~]$ ssh -l alice server.myuniv.org
[alice@server ~]$

If we launch rsc on the remote server, we will get very similar instructions:

[alice@server ~]$ rsc start
alice, your personal RStudio Server 2023.03.0+386 running R 4.3.1 is available on:

  <http://127.0.0.1:20612>

Importantly, if you are running from a remote machine without direct access
to server.myuniv.org, you need to set up SSH port forwarding first, which you
can do by running:

  ssh -L 20612:server.myuniv.org:20612 alice@login.myuniv.org

in a second terminal from you local computer.

Any R session started times out after being idle for 120 minutes.
WARNING: You now have 10 minutes, until 2023-04-17 17:30:33+01:00, to connect
and log in to the RStudio Server before everything times out.

In this case, we do:

[ab@local ~]$ ssh -L 20612:server.myuniv.org:20612 alice@login.myuniv.org
[alice@login ~]$

After this, the RStudio Server is available at http://127.0.0.1:20612 on our local machine. This works because port 20612 on our local machine is forwarded to port 20612 on the remote server, which is where the RStudio Server is served, via the login host.

Can we achieve the same with a single SSH connection?

Note that, the reason why we have to use two concurrent SSH connections, is that we cannot know what ports are available when we connect the first time to launch the RStudio Server. If we could know that, or if we would take a chance that it's available to use, we could do everything with one connections. For example, we have used port 20612 several times before, so we will try that this time too:

[ab@local ~]$ ssh -L 20612:server.myuniv.org:20612 alice@login.myuniv.org
[alice@login ~]$ ssh -l alice server.myuniv.org
[alice@server ~]$ rsc start --port=20612
alice, your personal RStudio Server 2023.03.0+386 running R 4.3.1 is available on:

  <http://127.0.0.1:20612>

Importantly, if you are running from a remote machine without direct access
to server.myuniv.org, you need to set up SSH port forwarding first, which you
can do by running:

  ssh -L 20612:server.myuniv.org:20612 alice@login.myuniv.org

in a second terminal from you local computer.

Any R session started times out after being idle for 120 minutes.
WARNING: You now have 10 minutes, until 2023-04-17 17:30:33+01:00, to connect
and log in to the RStudio Server before everything times out.

As before, the RStudio Server is available at http://127.0.0.1:20612.

Scenario 3: Remote machine with direct access to our local machine

Assume you can SSH to the remote server, directly or via a login host, and that the remote server can access your local machine directly via SSH. This is an unusual setup, but it might be the case when your local machine is connected to the same network as the server, e.g. a desktop and compute cluster at work. In this case, we can ask rsc to set up a reverse SSH tunnel to our local machine at the same time it launches the RStudio Server;

[ab@local ~]$ ssh -l alice server.myuniv.org
[alice@server ~]$ rsc start --revtunnel=ab@local.myuniv.org:20612
alice, your personal RStudio Server 2023.03.0+386 running R 4.3.1 is available on:

  <http://127.0.0.1:20612>

Any R session started times out after being idle for 120 minutes.
WARNING: You now have 10 minutes, until 2023-04-17 17:30:33+01:00, to connect
and log in to the RStudio Server before everything times out.