Configuring SSH

OpenSSH, sftp, rsync, VSCode, …

The OpenSSH configuration file is a plain text file that defines Hosts with short, easy to type names and corresponding full DNS names (or IPs) and advanced configuration options, which private key to use, etc. This file being picked up and read by multiple SSH clients or other applications that use the SSH protocol to connect to the cluster. Most clients let you override the defaults in this file for any given login.

Config file location

It is usually located in your home directory or user profile directory under .ssh/config, i.e.

OpenSSH config location

~/.ssh/config
/home/$USERNAME/.ssh/config

~/.ssh/config
/User/$USERNAME/.ssh/config

%USERPROFILE%\.ssh\config
C:\Users\your_username\.ssh\config

OpenSSH config file format

After general options that apply to all SSH connections, you can define a line Host my_shorthand, followed by options that will apply to this host only, until another Host xyz line is encountered. See the OpenSSH documentation for a full list of available options.

Simple configuration examples

Here are different blocks of configuration options you can copy-paste into your config file. You can mix-and-match these, choose the ones you need. Just make sure to replace User xyz with your respective username and if necessary, the path/filename of your private key.

SCC with VPN/Wireguard or inside GÖNET

Host SCC
	Hostname login-mdc.hpc.gwdg.de
	User jdoe1
	IdentityFile ~/.ssh/id_ed25519

Host SCC-transfer
	Hostname transfer-scc.hpc.gwdg.de
	User jdoe1
	IdentityFile ~/.ssh/id_ed25519

SCC from outside GÖNET, without VPN

Host gwdg-login # not part of the HPC-cluster!
	Hostname login.gwdg.de
	User jdoe1
	IdentityFile ~/.ssh/id_ed25519

Host gwdg-login-transfer # not part of the HPC-cluster!
	Hostname transfer.gwdg.de
	User jdoe1
	IdentityFile ~/.ssh/id_ed25519

Host SCC
	Hostname login-mdc.hpc.gwdg.de
	User jdoe1
	IdentityFile ~/.ssh/id_ed25519
	ProxyJump gwdg-login

Host SCC-transfer
	Hostname transfer-scc.hpc.gwdg.de
	User jdoe1
	IdentityFile ~/.ssh/id_ed25519
	ProxyJump gwdg-login-transfer

Note

The gwdg-login and gwdg-login-transfer hosts are not usable if your HPC access is granted via the HPC Project Portal

NHR / HLRN

Host Emmy-p1
	Hostname glogin-p1.hpc.gwdg.de
	User nimjdoe
	IdentityFile ~/.ssh/id_ed25519

Host Emmy-p2
	Hostname glogin-p2.hpc.gwdg.de
	User nimjdoe
	IdentityFile ~/.ssh/id_ed25519

Host Emmy-p3
	Hostname glogin-p3.hpc.gwdg.de
	User nimjdoe
	IdentityFile ~/.ssh/id_ed25519

Host Grete
	Hostname glogin-gpu.hpc.gwdg.de
	User nimjdoe
	IdentityFile ~/.ssh/id_ed25519

KISSKI

Host KISSKI
	Hostname glogin9.hpc.gwdg.de
	User u10123
	IdentityFile ~/.ssh/id_ed25519

Advanced configuration examples

Here are more advanced example configuration for all our clusters with convenient shortcuts for advanced users. Adapt to your needs. To understand this, remember ssh parses it’s config top-down and first-come-first-serve.

That means, if for a given Host the same option appears multiple times, the first one counts and later values are ignored. But for options not defined earlier, values will apply from successive appearances. Note that if Hostname is not specified, the host value is used.

All frontend nodes, individually specified

# SCC jumphosts
Host gwdu19.gwdg.de gwdu20.gwdg.de login.gwdg.de transfer.gwdg.de
	User jdoe1
	IdentityFile ~/.ssh/id_ed25519

# SCC login nodes
Host gwdu101.gwdg.de gwdu102.gwdg.e gwdu108.gwdg login-mdc.hpc.gwdg.de
	User jdoe1
	IdentityFile ~/.ssh/id_ed25519
	# ProxyJump login.gwdg.de  # Uncomment if not on GÖNET

# SCC transfer node
Host transfer-scc.gwdg.de transfer-mdc.hpc.gwdg.de
	User jdoe1
	IdentityFile ~/.ssh/id_ed25519
	# ProxyJump transfer.gwdg.de  # Uncomment if not on GÖNET


# NHR/HLRN and KISSKI
Host glogin*.hpc.gwdg.de glogin*.hlrn.de
	User nimjdoe
	IdentityFile ~/.ssh/id_ed25519


# CIDBN
Host login-dbn02.hpc.gwdg.de
	User jdoe1
	IdentityFile ~/.ssh/id_ed25519
	# ProxyJump login.gwdg.de  # Uncomment if not on GÖNET


# sa/hh
Host ngs01.hpc.gwdg.de
	User jdoe1
	IdentityFile ~/.ssh/id_ed25519
	# ProxyJump login.gwdg.de  # Uncomment if not on GÖNET

Complex example using config file tricks

Host SCC
	Hostname login-mdc.hpc.gwdg.de
Host SCC-transfer
	Hostname transfer-mdc.hpc.gwdg.de
Host SCC SCC-transfer gwdu101 gwdu102 gwdu108
	Hostname %h.gwdg.de
	User jdoe1
	IdentityFile ~/.ssh/id_ed25519

Host myNHRproject1
	User u10123
Host myNHRproject2
	User u10456
Host NHR myNHRproject1 myNHRproject2
	Hostname glogin.hpc.gwdg.de
Host kisski
	Hostname glogin9.hpc.gwdg.de
	User u10789
Host glogin* glogin-gpu glogin-p3 kisski NHR myNHRproject1 myNHRproject2
	Hostname %h.hpc.gwdg.de
	User nimjdoe
	IdentityFile ~/.ssh/id_ed25519