Purdue University

Open OnDemand

Open OnDemand is an open-source HPC portal developed by the Ohio Supercomputing Center. Open OnDemand allows one to interact with HPC resources through a web browser and easily manage files, submit jobs, and interact with graphical applications directly in a browser, all with no software to install. Anvil has an instance of OnDemand available that can be accessed via ondemand.anvil.rcac.purdue.edu.

Link to section 'Logging In' of 'Open OnDemand' Logging In

To log into the Anvil OnDemand portal:

• Navigate to ondemand.anvil.rcac.purdue.edu
• Log in using your ACCESS username and password

  

• ACCESS Duo authentication is required to login to OnDemand. Consult Manage Multi-Factor Authentication with Duo for account setup instructions

  

The Anvil team continues to refine the user interface, please reach out to us in case of any queries regarding the use of OnDemand.

SSH Keys

Link to section 'General overview' of 'SSH Keys' General overview

To connect to Anvil using SSH keys, you must follow three high-level steps:

1. Generate a key pair consisting of a private and a public key on your local machine.
2. Copy the public key to the cluster and append it to $HOME/.ssh/authorized_keys file in your account.
3. Test if you can ssh from your local computer to the cluster directly.

Detailed steps for different operating systems and specific SSH client software are given below.

Link to section 'Mac and Linux:' of 'SSH Keys' Mac and Linux:

1. Run ssh-keygen in a terminal on your local machine.

   localhost >$ ssh-keygen
   Generating public/private rsa key pair.
   Enter file in which to save the key (localhost/.ssh/id_rsa):
   

   You may supply a filename and a passphrase for protecting your private key, but it is not mandatory. To accept the default settings, press Enter without specifying a filename.
   Note: If you do not protect your private key with a passphrase, anyone with access to your computer could SSH to your account on Anvil.

   Created directory 'localhost/.ssh'.
   Enter passphrase (empty for no passphrase):
   Enter same passphrase again:
   Your identification has been saved in localhost/.ssh/id_rsa.
   Your public key has been saved in localhost/.ssh/id_rsa.pub.
   The key fingerprint is:
   ... 
   The key's randomart image is:
   ...
   

   By default, the key files will be stored in ~/.ssh/id_rsa and ~/.ssh/id_rsa.pub on your local machine.

2. Go to the ~/.ssh folder in your local machine and cat the key information in the id_rsa.pub file.

   localhost/.ssh>$ cat id_rsa.pub
   ssh-rsa XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
   XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX= localhost-username@localhost
   

3. For your first time login to Anvil, please log in to Open OnDemand ondemand.anvil.rcac.purdue.edu using your ACCESS username and password.

4. Once logged on to OnDemand, go to the Clusters on the top toolbar. Click Anvil Shell Access and you will be able to see the terminal.

   

   =============================================================================
   ==                    Welcome to the Anvil Cluster                         ==                                            
   ……               
   =============================================================================
   
   **                        DID YOU KNOW?                                    **
   ……
   *****************************************************************************
   
   x-anvilusername@login04.anvil:[~] $ pwd
   /home/x-anvilusername
   

5. Under the home directory on Anvil, make a .ssh directory using mkdir -p ~/.ssh if it does not exist.
   Create a file ~/.ssh/authorized_keys on the Anvil cluster and copy the contents of the public key id_rsa.pub in your local machine into ~/.ssh/authorized_keys.

   x-anvilusername@login04.anvil:[~] $ pwd
   /home/x-anvilusername
   
   x-anvilusername@login04.anvil:[~] $ cd ~/.ssh
   
   x-anvilusername@login04.anvil:[.ssh] $ vi authorized_keys
   
   # copy-paste the contents of the public key id_rsa.pub in your local machine (as shown in step 2) to authorized_keys here and save the change of authorized_keys file. Then it is all set! #
   

6. Test the new key by SSH-ing to the server. The login should now complete without asking for a password.

   localhost>$ ssh x-anvilusername@anvil.rcac.purdue.edu
   =============================================================================
   ==                    Welcome to the Anvil Cluster                         ==
   ...
   =============================================================================
   x-anvilusername@login06.anvil:[~] $
   

7. If the private key has a non-default name or location, you need to specify the key by ssh -i my_private_key_name x-anvilusername@anvil.rcac.purdue.edu.

Link to section 'Windows:' of 'SSH Keys' Windows:

PuTTY:

1. Launch PuTTYgen, keep the default key type (RSA) and length (2048-bits) and click Generate button.

   

2. Once the key pair is generated:

   Use the Save public key button to save the public key, e.g. Documents\SSH_Keys\mylaptop_public_key.pub

   Use the Save private key button to save the private key, e.g. Documents\SSH_Keys\mylaptop_private_key.ppk. When saving the private key, you can also choose a reminder comment, as well as an optional passphrase to protect your key, as shown in the image below. Note: If you do not protect your private key with a passphrase, anyone with access to your computer could SSH to your account on Anvil.

   

   From the menu of PuTTYgen, use the "Conversion -> Export OpenSSH key" tool to convert the private key into openssh format, e.g. Documents\SSH_Keys\mylaptop_private_key.openssh to be used later for Thinlinc.

3. Configure PuTTY to use key-based authentication:

   Launch PuTTY and navigate to "Connection -> SSH ->Auth" on the left panel, click Browse button under the "Authentication parameters" section and choose your private key, e.g. mylaptop_private_key.ppk

   

   Navigate back to "Session" on the left panel. Highlight "Default Settings" and click the "Save" button to ensure the change is in place.

4. For your first time login to Anvil, please log in to Open OnDemand ondemand.anvil.rcac.purdue.edu using your ACCESS username and password.

5. Once logged on to OnDemand, go to the Clusters on the top toolbar. Click Anvil Shell Access and you will be able to see the terminal.

   

   =============================================================================
   ==                    Welcome to the Anvil Cluster                         ==                                            
   ……               
   =============================================================================
   
   **                        DID YOU KNOW?                                    **
   ……
   *****************************************************************************
   
   x-anvilusername@login04.anvil:[~] $ pwd
   /home/x-anvilusername
   

6. Under the home directory on Anvil, make a .ssh directory using mkdir -p ~/.ssh if it does not exist.
   Create a file ~/.ssh/authorized_keys on the Anvil cluster and copy the contents of the public key id_rsa.pub in your local machine into ~/.ssh/authorized_keys.

   x-anvilusername@login04.anvil:[~] $ pwd
   /home/x-anvilusername
   
   x-anvilusername@login04.anvil:[~] $ cd ~/.ssh
   
   x-anvilusername@login04.anvil:[.ssh] $ vi authorized_keys
   
   # copy-paste the contents of the public key id_rsa.pub in your local machine (as shown in step 2) to authorized_keys here and save the change of authorized_keys file. Then it is all set! #
   

   and copy the contents of public key from PuTTYgen as shown below and paste it into ~/.ssh/authorized_keys. Please double-check that your text editor did not wrap or fold the pasted value (it should be one very long line).

    

   

7. Test by connecting to the cluster and the login should now complete without asking for a password. If you chose to protect your private key with a passphrase in step 2, you will be prompted to enter the passphrase when connecting.

ThinLinc

For your first time accessing Anvil using ThinLinc client, your desktop might be locked after it has been idle for more than 5 minutes. It is because in the default settings, the "screensaver" and "lock screen" are turned on. To solve this issue, please refer to the FAQs Page.

Anvil provides Cendio's ThinLinc as an alternative to running an X11 server directly on your computer. It allows you to run graphical applications or graphical interactive jobs directly on Anvil through a persistent remote graphical desktop session.

ThinLinc is a service that allows you to connect to a persistent remote graphical desktop session. This service works very well over a high latency, low bandwidth, or off-campus connection compared to running an X11 server locally. It is also very helpful for Windows users who do not have an easy to use local X11 server, as little to no setup is required on your computer.

There are two ways in which to use ThinLinc: preferably through the native client or through a web browser.

Browser-based Thinlinc access is not supported on Anvil at this moment. Please use native Thinlinc client with SSH keys.

Link to section 'Installing the ThinLinc native client' of 'ThinLinc' Installing the ThinLinc native client

The native ThinLinc client will offer the best experience especially over off-campus connections and is the recommended method for using ThinLinc. It is compatible with Windows, Mac OS X, and Linux.

• Download the ThinLinc client from the ThinLinc website.
• Start the ThinLinc client on your computer.
• In the client's login window, use desktop.anvil.rcac.purdue.edu as the Server and use your Anvil username x-anvilusername.
• At this moment, an SSH key is required to login to ThinLinc client. For help generating and uploading keys to the cluster, see SSH Keys section in our user guide for details.

Link to section 'Configure ThinLinc to use SSH Keys' of 'ThinLinc' Configure ThinLinc to use SSH Keys

• To set up SSH key authentication on the ThinLinc client:

  • Open the Options panel, and select Public key as your authentication method on the Security tab.

    

  • In the options dialog, switch to the "Security" tab and select the "Public key" radio button:

    

  • Click OK to return to the ThinLinc Client login window. You should now see a Key field in place of the Password field.

  • In the Key field, type the path to your locally stored private key or click the ... button to locate and select the key on your local system. Note: If PuTTY is used to generate the SSH Key pairs, please choose the private key in the openssh format.

    

• Click the Connect button.
• Continue to following section on connecting to Anvil from ThinLinc.

Link to section 'Connecting to Anvil from ThinLinc' of 'ThinLinc' Connecting to Anvil from ThinLinc

• Once logged in, you will be presented with a remote Linux desktop running directly on a cluster login node.
• Open the terminal application on the remote desktop.
• Once logged in to the Anvil login node, you may use graphical editors, debuggers, software like Matlab, or run graphical interactive jobs. For example, to test the X forwarding connection issue the following command to launch the graphical editor geany:

  $ geany

• This session will remain persistent even if you disconnect from the session. Any interactive jobs or applications you left running will continue running even if you are not connected to the session.

Link to section 'Tips for using ThinLinc native client' of 'ThinLinc' Tips for using ThinLinc native client

• To exit a full-screen ThinLinc session press the F8 key on your keyboard (fn + F8 key for Mac users) and click to disconnect or exit full screen.
• Full-screen mode can be disabled when connecting to a session by clicking the Options button and disabling full-screen mode from the Screen tab.