.. _compute_canada:

Compute Canada (DRAC)
---------------------

The `Digital Research Alliance of Canada <https://www.alliancecan.ca/en>`_, commonly referred to simply as 'Compute Canada', is the nation-wide HPC system for Canadian research institutions.
Compute Canada is not a single cluster, but rather is a consortium of different HPC clusters that are all accessed by a shared interface. If you are based at a
research institution in Canada, you most likely use a Compute Canada cluster.

Compute Canada clusters support either password or SSH key-file based logins, and all clusters currently mandate two-factor authentication using the DUO authentication system.

For general instructions on getting started with Compute Canada, please see `<https://docs.alliancecan.ca/wiki/Getting_started>`_.

Digichem supports both password-based and key-file-based logins for Compute Canada.

Password Logins
_______________

If you normally login to Compute Canada using a password, you can follow these setup instructions.

#. Follow the first steps of the :ref:`getting started guide <get_started_connect>` as normal.
#. When you are asked 'How do you normally login?', you should *untick* the **I use a password** option, and *tick* the **I use a one-time password** option instead. Leave the **I use a key file** option *unticked*:
    
   .. image:: /_static/installation/setup/OTP.png

   .. hint::
    Even though you are using a password, you should **not** use the 'I use a password' option. This is because all passwords for Compute Canada are provided 'on-demand'
    (which is what a 'one-time password' is) even though your password rarely changes.

#. When you click **Next**, you will first be prompted for your normal password:
   
   .. image:: /_static/installation/setup/OTP_prompt.png

   Enter this, and then click **Submit**.
#. Next, you will be prompted for your DUO second factor:

   .. image:: /_static/installation/setup/OTP_duo.png

   You can either enter a passcode from the DUO app directly, or enter a number to send a push notification to one of your supported devices.
   Enter your passcode or device number, and then click **Submit** once more.
#. Digichem will then log you in, and you can continue with the remainder of the :ref:`getting started guide <get_started_license>`.


SSH Key Logins
______________

If you normally login to Compute Canada without using a password, you can follow these setup instructions.

#. Follow the first steps of the :ref:`getting started guide <get_started_connect>` as normal.
#. When you are asked 'How do you normally login?', you should *untick* the **I use a password** option, and *tick* both the **I use a one-time password** and **I use a key file** options:

   .. image:: /_static/installation/setup/OTP_keyfile.png

#. Select your private key file from your local machine. If your private key is encrypted, remember to also specify the password in the **Key file password** box:
    
   .. image:: /_static/installation/setup/OTP_keyfile_filled.png

   .. admonition::
        On Windows machines

        If you generated your private key using PuttyGen, you may receive an error in Digichem like this:

        .. image:: /_static/installation/setup/bad_key_format.png
        

        Don't panic, your private key is simply saved in the wrong format. See how to convert it :ref:`here <convert_putty_keys>`.

#. When you click **Next**, you will be prompted for your DUO second factor:

   .. image:: /_static/installation/setup/OTP_keyfile_duo.png

   You can either enter a passcode from the DUO app directly, or enter a number to send a push notification to one of your supported devices.
   Enter your passcode or device number, and then click **Submit** once more.
#. Digichem will then log you in, and you can continue with the remainder of the :ref:`getting started guide <get_started_license>`.


.. _convert_putty_keys:


Converting Putty Keys
_____________________

Digichem cannot directly read private keys stored in the Putty format (the .ppk file). Fortunately, it's easy to convert them using PuttyGen.

#. Open PuttyGen.
#. Click on **Conversions** and then **Import key**, and load your private key file (.ppk):

   .. image:: /_static/installation/setup/puttygen_import.png

#. Next, click on **Conversions** and then **Export OpenSSH key**, and save your new private key file somewhere you can remember:

   .. image:: /_static/installation/setup/puttygen_export.png

#. You can now use your freshly converted private key file to connect to your server in Digichem.