Login to Cluster

NOTE

The following procedure require to register with ArunHPCC.
If you don't have and account yet, please register your account.

Login into Arun HPCC needs an user account on the cluster system. And by policy we do not allow login with a password into the system. The user authentication is done by SSH Public Key.

Once you register with Arun HPCC portal, you've to submit a SSH Public Key to login to Arun HPCC cluster.

Creating SSH key

SSH key comes with a key pair, private key and public key. To use SSH keys, public key must be distributed and added to the server to be log in as authorized key. Frist generate a SSH key pair as follows:

NOTE

Assuming you already have access to a linux based termimal. If you don't have Linux or MacOS you can also use Windows operating system. Installing git can provide a bash shell in Windows. In recent version of Windows there is native bash shell.

Generate SSH key pair

[user@machine] $ ssh-keygen -t rsa
1

Follow the instruction on the prompt and complete the key generation by pressing enter.

NOTE

The passphrase will provide one more layer of security. But please note, every time you login with the SSH key you've to enter the passphrase manually.

Here is an example of a SSH key generation without a passphrase: ssh-keygen It will create a SSH RSA key pair of 2048 bit long with SHA256 algorithm in default location:

  • Private key : ~/.ssh/id_rsa
  • Public key : ~/.ssh/id_rsa.pub

Check the SSH public key

Once you have SSH key generated, check the public key using simple cat command: ssh-pub-key

Share the public key

Now copy the public key string and email to Arun-HPCC admin. You can also send the id_rsa.pub file as an attachment. Once received the public key will be added to the authorized keys in the cluster. And as long as the private key available you can login to Arun-HPCC cluster without any password. After the user is created Arun-HPCC admin will notify you via Email. Your user name will be provided in the Email.

NOTE

Keep this SSH key pair very safely. If you run the ssh-keygen command again it will override any previously generated key (default keys). Without these key you can not login to the server. We recommend to rename the key to identify and keep a backup copy of the key somewhere safe. If for any reason the default key is lost you can restore from the backup.

Login into the Cluster

NOTE

Following login process is with default ssh_key pair, id_rsa and id_rsa.pub located in ~/.ssh/ directory.

To login into the Arun-HPCC cluster from a bash terminal use ssh command as follows:

[user@machine] $ ssh {user_name}@arun-hpcc.ru.ac.bd
1

Use the username given by the confirmation email from admin. If the login is successfull you will have a login shell. E.g. : ssh-login

Login into the Cluster using Private Key

NOTE

Assuming the registered key pair named arun-hpcc_id_rsa and arun-hpcc_id_rsa.pub located in ~/arun-hpcc-keys directory

Login into the cluster using private key as follows:

[user@machine] $ ssh -i ~/arun-hpcc-keys/arun-hpcc_id_rsa {user_name}@arun-hpcc.ru.ac.bd
1

Important

Do not loose the registered key pair. It is recommended to keep backup of the registered ssh key pair in a secure place. And the private key must not be shared with anyone. Using this registered key pair user can login from any computer terminal, so please take a very good care of the key pair.

NOTE

Please notify to Arun-HPCC admin in case of any problem at admin@arun-hpcc.ru.ac.bd.