Computing

Computing and software

Requirements

The participant should bring a laptop with Remote Desktop (RDP) client software installed. The client software is installed by default in Windows and in most linux distributions (remmina, xfreerdp in freerdp2-x11). With Mac, you have to install the free client from the standard Apple software sources (Microsoft Remote Desktop). x2go works also.

You can and should test the software by trying to connect tube.utu.fi, if you get a login screen, the client is working.

What is a container?

Instead of exposing our full computing server to the dangers of the internet, we have built a confined environment, like a virtual server inside a server called ’course’ container. Host tube.utu.fi is just an endpoint of a ’wormhole’ that leads to the course container.

Connecting to the container

You can use ssh, RDP and x2go to connect to the container.

Connecting with RDP

With RDP, you get a full desktop instead of one terminal like in ssh connection. The client software is installed by default in Windows and in most linux distributions (remmina, xfreerdp in freerdp2-x11). With Mac, you have to install the free client from the standard Apple software sources (Microsoft Remote Desktop).

If you terminate the connection without logging out, you will get the same session in the subsequent login. The session will not of course survive reboots, so save your data before leaving!

We will use the standard RDP port in the connection, so appending a port number (e.g 42000 in the images) is not necessary (you can leave it out).

In Mac:

In Linux (remmina):

In Windows 10

Use case 2 in the following link: Use Remote Desktop to connect to the PC you set up

https://support.microsoft.com/en-us/help/4028379/windows-10-how-to-use-remote-desktop

Using SSH to connect

In case of ssh, the command is

 ssh -Y USER@tube.utu.fi

on Linux.

Possible but not probable SSH key problem

If you get an error message like this:

 @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
 @    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
 @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
 IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
 Someone could be eavesdropping on you right now (man-in-the-middle attack)!
 It is also possible that a host key has just been changed.
 The fingerprint for the ECDSA key sent by the remote host is
 c4:98:bb:5e:73:fa:e7:0c:94:2c:5b:7c:33:e6:ea:7c.
 Please contact your system administrator.
 Add correct host key in /home/juanauh/.ssh/known_hosts to get rid of this message.
 Offending ECDSA key in /home/juanauh/.ssh/known_hosts:26
   remove with: ssh-keygen -f "/home/juanauh/.ssh/known_hosts" -R tube.utu.fi
 ECDSA host key for tube.utu.fi has changed and you have requested strict checking.
 Host key verification failed.

Then do what it says :-)! As an example:

 ssh-keygen -f "/home/juanauh/.ssh/known_hosts" -R tube.utu.fi

Of course you have to use the command line that is in the actual error message.

In Macs you have to figure out the offending key by yourself (no help is given).

Enjoy!