- Jupyter Notebooks and Lab e.g. on `Jupyterhub@srvx1` or `jupyterhub@jet`
and `atom`. This is simple editor available on any platform and it can be extended with packages to become a full grown IDE with the power of open source.
## Q: How to transfer files between two VPN networks?
## General Access
Please use these methods to access the servers:
1. SSH
2. JupyterHub
3. VNC
## SSH
**From any computer in the IMGW subnet**: Log in via ssh by typing either of the following in a terminal (there are two redundant login nodes, jet01 and jet02). Replace `[USERNAME]` with your own.
```bash
ssh -X[USERNAME]@srvx1.img.univie.ac.at
ssh -X[USERNAME]@srvx8.img.univie.ac.at
ssh -X[USERNAME]@jet01.img.univie.ac.at
ssh -X[USERNAME]@131.130.157.215
ssh -X[USERNAME]@jet02.img.univie.ac.at
ssh -X[USERNAME]@131.130.157.216
```
The `-X` option enables X11 forwarding via ssh, i.e., permits opening graphical windows.
**From eduroam**: You should be able to log in as above.
**From the outer world**: First connect to the [UniVie VPN](https://zid.univie.ac.at/en/vpn/), then start up a terminal and log in as above.
If you are a guest, you can apply for a [guest u:account](https://zid.univie.ac.at/uaccount/#c11096). This will give you access to eduroam and to the VPN. Your application needs to be endorsed by a staff member, who also determines the expiration date of the account.
## VNC
**Be aware! Everyone with the VNC password will get access to your account**
It is recommended not to use VNC. Use **jupyterhub** or **screen** instead.
The VNC (Virtual Network Computing) allows to view a graphical user interface (GUI) from a remote server in an viewer application. This can be used to launch GUI programs on the servers.
Xvnc is the Unix VNC server. Applications can display themselves on Xvnc as if it were a normal display, but they will appear on any connected VNC viewers rather than on a physical screen. The VNC protocol uses the TCP/IP ports 5900+N, where N is the display number.
### Connecting, setting the window manager
Use a VNC client (e.g. the [RealVNC VNC Viewer](https://www.realvnc.com/en/connect/download/viewer/windows/) on Windows, or [Remmina](https://remmina.org/) on any Linux distribution) and connect to `131.130.157.215:[DISPLAY]`.
The VNC server will automatically start a graphical window manager/desktop environment. Details are stored in `.vnc/xstartup`. Your default configuration will load GNOME, and `.vnc/xstartup` will be something like this:
```bash
#!/bin/sh
unset SESSION_MANAGER
unset DBUS_SESSION_BUS_ADDRESS
/etc/X11/xinit/xinitrc
# Assume either Gnome will be started by default when installed
# We want to kill the session automatically in this case when user logs out. In case you modify
# /etc/X11/xinit/Xclients or ~/.Xclients yourself to achieve a different result, then you should
# be responsible to modify below code to avoid that your session will be automatically killed
if[-e /usr/bin/gnome-session ];then
vncserver -kill$DISPLAY
fi
```
It is recommended to use IceWM instead. This is a more lightweight alternative to GNOME. To switch to IceWM, first log out from GNOME and disconnect from your VNC viewer, then change your `.vnc/xstartup` to this:
`xrandr` gives you a list of available resolutions, that can be used.
Change the resolution to e.g. 1920x1080 (HD):
```
xrandr -s 1920x1080 -d $DISPLAY
```
Adding resolutions according to your display's resolution have a look here: [add_xrandr_resolution.sh](add_xrandr_resolution.sh)
## Screen
[Screen](https://wiki.ubuntuusers.de/Screen/) is terminal session manager, that allows to start processes and reconnect to these processes after disconnection.
This starts a new session
```bash
screen -S longjob
```
You can detach from this session with `CTRL + A + D` and reconnect again with `screen -r`.
Multiple Sessions can be created and the output saved.
## Jupyterhub
On SRVX1 the TeachingHub and on Jet01 the ResearchHub is running and available to users and students. Connect to either [https://srvx1.img.univie.ac.at](https://srvx1.img.univie.ac.at) from everywhere or [https://jet01.img.univie.ac.at](https://jet01.img.univie.ac.at) from within the university network.
# Q: ssh using key authentication?
In order to connect passwordless to a remote server a key needs to be generated.
