Teleport is software which provides an SSH Jump Host (or Bastion host) service in a secure, modern way, with support for role-based access control and single sign-on.

Overview

The Teleport It is used to access a number of services at ECMWF, including our Atos HPCF and ECS services. The service provides:

• Single SSH hop from client systems anywhere on the internet to servers inside ECMWF (ecGate, HPC, etc)
• Re-authentication required only every 12 hours (usually once per working day)
• Integration with standard tools such as the OpenSSH ssh client, scp, and ssh-agentWeb-SSH interface for in-browser terminal access, with scp
• X11 and Port forwarding

The single sign-on step is performed using an application called "tsh", every 12 hours.After . After that you use standard ssh or scp to connect to systems inside ECMWF.

Alternatively you can have simple terminal access in a web browser. 

Downloading tsh 

The tsh application is required to perform user authentication once every 12 hours.

tsh is open source, very portable, and has minimal dependencies.

• Download from the Gravitational website and place into your $PATH 

The binary is available for Linux 32-bit, 64-bit, and ARM, as well as Windows 64-bit and a signed package for MacOS.

MacOS users can also use homebrew for installation (brew install teleport).

User Authentication

Once every 12 hours, you will need to refresh your tokens with the tsh command, through your web browser.

First Time

Run tsh, giving the location of our gateway:

tsh login --proxy=shell.ecmwf.int:443

Your default web browser will open and you should login with your email address, ECMWF password, and then HID (ActivID) Token code.

Subsequent Occasions

tsh login

Connecting to hosts through the gateway

OpenSSH 7.3 or later has a simple command line option to connect via our gateway (shell.ecmwf.int) to the destination-host:

ssh -J username@shell.ecmwf.int username@destination-host

For example, if your username is ab0 and you wish to connect to ecgate:

ssh -J ab0@shell.ecmwf.int ab0@ecgate

The OpenSSH configuration setting for this is named ProxyJump:

Host ecgate
  User ab0
  ProxyJump ab0@shell.ecmwf.int

See the Legacy Configuration note below if your ssh client is older than 7.3.

If your connection fails after working for some time, it could be because your tokens have expired. You can check them:

$ tsh status
> Profile URL:  https://shell.ecmwf.int:443
  Logged in as: firstname.lastname@ecmwf.int
  Cluster:      shell.ecmwf.int
  Roles:        *
  Logins:       ab0
  Valid until:  2020-06-22 23:26:30 +0100 BST [EXPIRED]
  Extensions:   permit-X11-forwarding, permit-agent-forwarding, permit-port-forwarding, permit-pty

From OpenSSH 8.4 the client may refuse to connect with the cryptic message: "Connection closed by UNKNOWN port 65535".

This is because the Teleport system has to remain compatible with some old OpenSSH server versions. The problem will go away when our Bologna data centre is used instead.

The fix is to add this extra line to your OpenSSH configuration:

Host ecgate
  User ab0
  ProxyJump ab0@shell.ecmwf.int
  PubkeyAcceptedKeyTypes +ssh-rsa-cert-v01@openssh.com

Destination Hosts available

The hosts directly available through the Teleport gateway are:

• ECGATE (interactive node only)
• CCA and CCB login nodes
• HPC2020 TEMS

...

• Linux VDI (both legacy OpenSUSE and CENTOS 8 beta)
• Physical office workstations

To access any other host, the ProxyJump feature allows chaining by using a comma, like so:

ssh -J ab0@shell.ecmwf.int,ab0@ecgate ab0@lxc

You can also set password-less login, as below.

...

Configuring password-less login

Add the Teleport certificate authority to your ~/.ssh/authorized_keys file, on the relevant system at ECMWF, e.g. ecgate, cca:

curl -fs https://nexus.ecmwf.int/repository/internal-teleport-configs/prod/teleport_user_ca.pub >> ~/.ssh/authorized_keys

Here are the instructions on how to set it up depending on your platform:

• Teleport SSH Access - Mac configuration
• Teleport SSH Access - Linux configuration
• Teleport SSH Access - Windows Terminal and Powershell configuration
• Teleport SSH Access - Windows Subsystem for Linux (WSL)
• Teleport SSH Access - Windows MobaXterm configuration
• Teleport SSH Access - Windows Cygwin configuration

  
  

Terminal Access in a Web Browser

You can open a tabbed terminal in the web browser, with support for SCP upload and download.

...

...

Browse to  http://webshell.ecmwf.int/destination-host/username (replacing destination-host and username with your selection).

For example, if your username is ab0 and you wish to connect to ecgate:

http://webshell.ecmwf.int/ecgate/ab0

If you open another tab inside the web terminal, use the QUICK LAUNCH box and enter "username@destination-host:22", for example ab0@ecgate:22.

Windows Clients

There are various ways to initiate SSH from Windows 10, so it depends on your system and your preferences.

...

1. Install MobaXterm if it is not already on your system
2. Download tsh (you may need to instruct antivirus software to ignore the file)
3. Start MobaXterm
4. Login using tsh (you will always need to specify the --proxy setting)
5. Use the following in $HOME/.ssh/config (MobaXterm's home):

Host ecgate
  User ab0
  ProxyCommand ssh -q -i c:/users/ab0/.tsh/keys/shell.ecmwf.int/firstname.lastname@ecmwf.int -W %h:%p ab0@shell.ecmwf.int
  IdentityFile c:/users/ab0/.tsh/keys/shell.ecmwf.int/firstname.lastname@ecmwf.int

...

1. Start the Windows SSH Agent Service
2. Download tsh (you may need to instruct antivirus software to ignore the file)
3. Login using tsh (you will always need to specify the --proxy setting)
4. Use an SSH config as below:

# Windows currently has a bug, you need the full path to ssh or you will get:
# posix_spawn: No such file or directory

Host *.ecmwf.int
  User ab0
  ProxyCommand C:\Windows\System32\OpenSSH\ssh.exe -q -W %h:%p ab0@shell.ecmwf.int

# this assumes the SSH Agent is running, otherwise add:
# Host shell.ecmwf.int
#   IdentityFile ~/.tsh/keys/shell.ecmwf.int/firstname.lastname@ecmwf.int

...

The Windows 10 Terminal is a decent tabbed command line interface (albeit with no X11 support).

...

{
  "guid": "{717406b0-06cb-454c-a0c4-875267fa373d}", # run "[guid]::NewGuid()" in a PowerShell to generate this
  "name": "ecGate",
  "commandline": "ssh ab0@ecgate.ecmwf.int"
  "suppressApplicationTitle": true,
  "hidden": false,
  "fontSize": 10,
  "fontFace": "Fira Code",
  "cursorShape": "filledBox",
  "cursorColor": "#073642",
  "colorScheme": "Solarized Dark",
},

Other Notes

SSH Agent is required

If you have logged in but ssh fails to connect, it may be that your SSH agent is not running.

The Agent can be started and tokens refreshed this way:

eval $(ssh-agent -s)
tsh logout
tsh login

And this will make sure the Agent continues to run in your environment:

echo 'eval $(ssh-agent -s)' >> ~/.bash_profile

SCP, X11, Agent, and Port Forwarding

SCP, Agent forwarding, X11 forwarding, and Port forwarding (including SOCKS proxy), all work through the Teleport gateway. A nice application of port forwarding with Teleport is the use of the ecflow_ui client on your local system to follow ecflow suites running at ECMWF.  See Teleport - using local ecflow_ui for more details.

For scp you can use the -o option:

scp -o ProxyJump=ab0@shell.ecmwf.int ab0@ecgate:/remote/file/path /local/file/path

X11 under macOS

$ brew cask install xquartz
# start xquartz app
$ export DISPLAY=:0
$ ssh -X ....

Legacy Configuration

For OpenSSH clients older than 7.3, the following configuration can be used:

# ~/.ssh/config file:
Host ecgate
  User ab0
  ProxyCommand /usr/bin/ssh -q -W %h:%p ab0@shell.ecmwf.int

Difficult client environments

You might not be able to download and run tsh, or access our web login service, or run the SSH Agent, from where you wish to use ssh.

Instead you can use (or copy) the identity files which tsh stores in $HOME:

# ~/.ssh/config file:
Host ecgate
  User ab0
  IdentityFile ~/.tsh/keys/shell.ecmwf.int/firstname.lastname@ecmwf.int
  ProxyCommand /usr/bin/ssh -q -i ~/.tsh/keys/shell.ecmwf.int/firstname.lastname@ecmwf.int -W %h:%p ab0@shell.ecmwf.int

This is a good way to access Teleport credentials via a shared file system from any host.

Even more difficult client environments

Recent Fedora Linux distributions (such as Fedora-33) using OpenSSH 8.4p1 no longer accept the "ssh-rsa" signature scheme using the SHA-1 hash algorithm in conjunction with the RSA public key algorithm.

As a workaround for this problem, you  may need to add ssh-rsa as a PubkeyAcceptedKeyTypes to your ~/.ssh/config file: