Howto::Access rlogin service

Introduction

Rlogin is our primary teaching resource. It allows faculty and students to work and develop software in a consistent Linux software environment.

Account

Access is controlled by a Computer Science specific account. Accounts for Non-CS students are disabled after each semester.

• New or returning students can create a CS account online at https://admin.cs.vt.edu/create/
• Students can reset their password online at https://admin.cs.vt.edu/reset/

Primary Access

The primary way of accessing rlogin is using an SSH client. Linux and Macs usually come with SSH client already active. Windows users can install the client following these directions: https://code.visualstudio.com/docs/remote/troubleshooting#_installing-a-supported-ssh-client

You can log into rlogin.cs.vt.edu using either your CS username/password OR your VT username/password.

Using just your VT account

Non-CS affiliates (such as a non-CS major taking a CS class) can log in using just their VT username and password.

• You need a SSH client.
• Run the following command
  • <username>@vt.edu@rlogin.cs.vt.edu replace <username> with your VT username
• You will be prompted for your VT password
• It will silently use your default VT Duo 2FA method. If you need to use an alternative Duo method, see VT's documentation: https://4help.vt.edu/sp?id=kb_article&sysparm_article=KB0010700&sys_kb_id=8377bde91bb4259063110f66624bcb3a&spa=1#ldap
• Once connected, we high recommend that you set up SSH key login Howto::SSH Key so you no longer need to use your VT password and Duo to log in every time.

Using your CS account

• Using ssh <username>@rlogin.cs.vt.edu will prompt for your CS password, not your VT password.
• You can still use your VT password by running ssh <username>@vt.edu@rlogin.cs.vt.edu
  • Note: your CS account and VT account are different UIDs, and have separate permissions. Your CS account can not access files owned by the VT account and vice-versa.

Access a Specific Node

Using the primary access will load balance users across all the nodes. Sometimes a user needs to access a specific node, such as running a tmux session. There are several ways you can access a specific node.

• List of node names: http://rlogin.cs.vt.edu/nodes.txt

Piggy Back

One of the easiest and quickest way to access a specific node is to simply SSH to rlogin.cs.vt.edu and use the SSH client there to directly connect to the specific node name.

• ssh <node>.rlogin

Portal

There is an additional SSH host that will give users a menu that allows access to a specific node.

• ssh <username>@portal.cs.vt.edu

IPv6

Each specific node has an IPv6 hostname of the format: <node>-rlogin.cs.vt.edu. If you have IPv6 access you can directly SSH to the node's IPv6 hostname. Note, that VT blocks port 22 at the border, so you will need to be on-campus or connect to the VT VPN to be able to connect.

• ssh <username>@<node>-rlogin.cs.vt.edu

SSH Bastion

With some client side configuration, portal can be used as a SSH bastion and allow access directly to a specific node name.

• Locate or create your client SSH config file, the location is OS specific. On Linux it is generally: ~/.ssh/config
• Edit the SSH config file and add the following block

Host *.rlogin
  ProxyCommand ssh -W %h:%p portal.cs.vt.edu

• Now directly SSH to a node name from your machine
  • ssh <username>@<node>.rlogin

Another way to Access

We have a new additional way to access rlogin/glogin through a web browser. This is still considered experimental, so some errors may occur. It allows both command line and graphical interfaces.

• https://portal.cs.vt.edu