Download and setup MobaXterm

Go to the MobaXterm website and download the free version. Make sure to select the Portable edition from the download page. Create a MobaXterm folder on your Windows user Documents one and uncompress inside it the contents of the downloaded zip file.

We chose to create the MobaXterm folder on that particular location and we will refer to that on this guide. You can, of course, select some other location of your preference if you wish.

Note

We will use my-ceci-cluster.example.com as a generic dummy address throughout the guide. When trying to follow the steps on your machine replace that by a real remote host of the CÉCI cluster you wish to use:

  • hmem (UCL): hmem.cism.ucl.ac.be
  • Lemaitre3 (UCL): lemaitre3.cism.ucl.ac.be
  • NIC4 (ULiège) : nic4.segi.ulg.ac.be
  • Hercules (UNamur): hercules.ptci.unamur.be
  • Dragon1 (UMons): dragon1.umons.ac.be
  • Vega (ULB): vega.ulb.ac.be

To decide which cluster is better suited for your kind of jobs, please check the details about them in the CÉCI clusters page.

1. Setup a shortcut for a remote session

  1. Double click the MobaXterm_Personal executable file inside the Documents\MobaXterm folder. You should see the MobaXterm main window like this one:
mobaxterm main
  1. Click on the Session icon on the top left corner.
  2. The Session settings configuration panel will open, select the SSH session type and you should see a window like this:
ssh settings window
  1. In the Remote host field introduce the cluster remote address my-ceci-cluster.example.com (check the note on top to find a valid address for your desired cluster). Tick the Specify username box and introduce your CÉCI username. Click the Advanced SSH settings tab and you will see these extra options:
advanced ssh options
  1. Tick the Use private key box and click on the icon on that field, a file browser will be opened, locate your id_rsa.ceci key file you received by e-mail. Take note that you should not change the location of the CÉCI key file. If you move it you will have to update its location in this setting section again, to allow MobaXterm to find it. Check that the SSH-browser type is set as SFTP protocol. The SSH settings tab should look like this at the end of the process:
ssh settings final options
  1. Press the OK button and you should be prompted for your passphrase. Enter here the passphrase you chose while filling the CÉCI web application form. The characters will be hidden and nothing at all will appear as you type (no circles, no symbols). You should connect to the cluster and be greeted by a screen similar to this one:

    hmem greeting

    On the left sidebar you will see on the Sftp tab a file browser of your home directory in the cluster. You will see by default many files whose names start with a dot (.) symbol. These are hidden files of the Linux environment and you should not delete nor move them. You can edit and customize them if you are aware of what you are doing.

  2. When you disconnect from the cluster (by typing exit or closing the terminal tab) you will find on the left sidebar on the Sessions tab a shortcut to the session you just setup. From now on, when you open MobaXterm, you can just double click that shortcut and you will start a remote session on my-ceci-cluster.example.com. If you wish you can also create a direct shortcut on your desktop. To do that, right click on the saved session name and choose Create a desktop shortcut, as shown below. An icon will appear on your Desktop which double clicking starts MobaXterm with a session on the cluster.

session desktop shortcut
  1. Now you can repeat these steps for the rest of the CÉCI clusters you are planning to use. You will have then a shortcut on the Sessions tab of the left sidebar for each of them to connect to.

2. Copying files to and from the cluster

After you succeeded to setup the shortcut for connecting to a cluster, as we noted on the step 6 of the previous section, you will see on the left sidebar on the Sftp tab a file browser on the cluster you are connected to.

You can simply drag and drop files from your computer to that panel and they will be copied to the cluster. The same is valid for retrieving files from the cluster to your computer.

If you right click on that panel, you will see different options to interact with the browser (see the figure below). Remember always to press the Refresh current folder button after you copied something or a new file or folder is created on the cluster.

session desktop shortcut

Note that you also have the right-click options directly available through the icons on the toolbar at the top of the panel.

3. Setup an SSH agent to avoid typing the passphrase at each login

After you successfully setup your cluster to connect by double clicking the shortcut, you will notice that you are prompted for the passphrase for each connection you make to a cluster. To avoid retyping it each time, you can setup an internal SSH agent in MobaXterm that will take care of unlocking the private key when you open the application.

and also choose to save the passphrase after having introduced it once.

  1. Open the MobaXterm program and go in the menu to Settings -> Configuration

  2. You should see the MobaXterm Configuration panel. In the General tab choose the MobaXterm passwords management option, a new panel will be opened, make sure that Save sessions passwords has the options Always and Save SSH keys passphrases as well selected as shown below and click OK.

    mobaxterm save passwords option
  3. Now go in the same MobaXterm Configuration panel to the SSH tab. Make sure that all the options below the SSH agents section are ticked.

  4. Press the + button in the Load following keys at MobAgent startup field and look for your id_rsa.ceci file, at the end the panel should like as this

    mobaxterm ssh agent setup

    Remember that you should not change the file location, otherwise you’ll have to come back to this settings to update it.

  5. Press OK and you will be prompted for restarting MobaXterm, choose to do so.

  6. When it is relaunched you will be asked for the private key passphrase at the beginning, after you introduced it correctly it will stay saved for all the forthcoming sessions. You should be able to double click in the shortcuts for the clusters and get connected directly.

4. Accesing the clusters from home or abroad

As the clusters are not accessible from outside the university networks, you will need to either use a VPN or an SSH gateway. Going through an SSH gateway can be entirely transparent provided your client is correctly configured. The CÉCI does not offer a gateway service so you need to refer to your local support team for more information:

  • UCL: you can use gwceci.cism.ucl.ac.be as SSH gateway using a CECI account. See the CISM documentation.
  • ULB: you can use hydra as SSH gateway. See the hydra documentation.
  • UMons: contact the local support team to learn how to setup the VPN.
  • UNamur: you can use hal.unamur.be using your UNamur identity or use the VPN (see UNamur intranet)
  • ULiège: you need to use the VPN service.

Note that you can use any Linux computer that is connected to your university network to which you have SSH access from your home or abroad to act as gateway.

4.1 Using a VPN

If you can setup a VPN on your machine no extra step is required. When enabling the VPN, the shortcuts you created previously will work transparently as if you were inside the university network.

4.2 Using a ssh gateway

If you have a ssh gateway available to use you will have to configure an additional shortcut for each cluster you plan to use outside the university network. Before starting to set up the gateway pass-through, make sure you followed the steps in the previous section to have an SSH agent running and forwarded.

Your local support team will provide you with the following information of the ssh gateway:

  • Gateway address: gateway.address
  • Port: 22 (this is the default if nothing is specified)
  • Username: <gatewayuser>
  • Password: <password if you connect with a password or passphrase if you connect with a passphrase-protected SSH key>
  • Private ssh key: <(optional) in case login is with SSH key pair authentication>

To access the clusters through it, you must create a new shortcut going through the same steps as explained before. But on the step 5, after doing the setup on Advanced SSH settings, you must go to the Network settings tab and introduce the information of the ssh gateway as shown below:

ssh gateway config

Note that if a private ssh key is required to access the gateway you should tick the Use private key box and then on the icon to browse for the key on your computer.

Press the OK button and the shortcut will be created.

Double clicking the shortcut on the Sessions tab will allow you to connect to the cluster from any location. You will be prompted for the gateway password or key-passphrase. If you are authenticated with a different private key from the CÉCI one, you can choose to also manage it by the MobatXterm Agent as explained before.

It is advisable to rename this new shortcut (by right clicking on it), introducing information to remind it is the one for external access.

It is important to note that you do not need to be outside the university network to test the SSH gateways. Going through a gateway works as well from within than from outside the university network. So be sure to test everything before you leave.