SSH configuration for Mac and Linux

# goto your homedirectory

cd

# create a .ssh directory

mkdir .ssh

# goto .ssh directory

cd ~/.ssh

# create a ssh keypair

ssh-keygen -t rsa -C HPC -f id_rsa_hpc

# enter 2 times a secret word called "passphrase"
# Put this passphrase in a "digital safe" ( p.e. KeepAss see: https://keepass.info/ ) because you need this later on.

# now you created 2 files like this

-rw------- 1 wvanburen users 1766 Mar 27 11:47 id_rsa_hpc
-rw-r--r-- 1 wvanburen users 385 Mar 27 11:47 id_rsa_hpc.pub

# copy and paste the content of the public-key named id_rsa_hpc.pub
# and mail this to hpc-systems@lists.umcutrecht.nl
# After the admins configured your public key on the gateway you can try to login into the hpc gateway by

ssh -i ~/.ssh/id_rsa_hpc -l wvanburen hpcgw.op.umcutrecht.nl

and enter your selfmade passphrase.
Once you entered the gateway you can continue to log in into the HPC by:

ssh hpcs03

ssh hpcs04

You can automate this procedure to create a ssh-config files called "config" in your .ssh directory.
This is an example.
Copy and save this file in the .ssh directory and call it config.

#############################################
# file : ~/.ssh/config
# date : 20200327
# expl : default ssh config file example 
#############################################

# usage : ssh hpcgw
Host hpcgw
  HostName hpcgw.op.umcutrecht.nl
  User wvanburen
  Protocol 2
  Port 22
  IdentityFile ~/.ssh/id_rsa_hpc

# usage : ssh gw2hpcs03
Host gw2hpcs03
  HostName hpcs03.op.umcutrecht.nl
  User wvanburen 
  Port 22
  Protocol 2
  ProxyCommand ssh -i ~/.ssh/id_rsa_hpc -l wvanburen hpcgw.op.umcutrecht.nl nc %h %p 2>/dev/null

# usage : ssh gw2hpcs03X
Host gw2hpcs03
  HostName hpcs03.op.umcutrecht.nl
  User wvanburen 
  Port 22
  Protocol 2
  ForwardX11 yes
  ProxyCommand ssh -X -i ~/.ssh/id_rsa_hpc -l wvanburen hpcgw.op.umcutrecht.nl nc %h %p 2>/dev/null

# usage : ssh gw2hpcs04
Host gw2hpcs04
  HostName hpcs04.op.umcutrecht.nl
  User wvanburen 
  Port 22
  Protocol 2
  ProxyCommand ssh -i ~/.ssh/id_rsa_hpc -l wvanburen hpcgw.op.umcutrecht.nl nc %h %p 2>/dev/null

# usage : ssh gw2hpcs04X
Host gw2hpcs04
  HostName hpcs04.op.umcutrecht.nl
  User wvanburen 
  Port 22
  Protocol 2
  ForwardX11 yes
  ProxyCommand ssh -X -i ~/.ssh/id_rsa_hpc -l wvanburen hpcgw.op.umcutrecht.nl nc %h %p 2>/dev/null

# usage : ssh gw2hpct01
Host gw2hpct01
  HostName hpct01.op.umcutrecht.nl
  User wvanburen 
  Port 22
  Protocol 2
  ProxyCommand ssh -i ~/.ssh/id_rsa_hpc -l wvanburen hpcgw.op.umcutrecht.nl nc %h %p 2>/dev/null

# usage : ssh gw2hpct02
Host gw2hpct02
  HostName hpct02.op.umcutrecht.nl
  User wvanburen 
  Port 22
  Protocol 2
  ProxyCommand ssh -i ~/.ssh/id_rsa_hpc -l wvanburen hpcgw.op.umcutrecht.nl nc %h %p 2>/dev/null

# usage : ssh hpcs03
Host hpcs03
  HostName hpcs03.op.umcutrecht.nl
  User wvanburen 
  Port 22
  Protocol 2

# usage : ssh hpcs03X
Host hpcs03X
  HostName hpcs03.op.umcutrecht.nl
  User wvanburen 
  Port 22
  ForwardX11 yes

# usage : ssh hpcs04
Host hpcs04
  HostName hpcs04.op.umcutrecht.nl
  User wvanburen 
  Port 22
  Protocol 2

# usage : ssh hpcs04X
Host hpcs04X
  HostName hpcs04.op.umcutrecht.nl
  User wvanburen 
  Port 22
  Protocol 2
  ForwardX11 yes

# usage : ssh hpct01
Host hpct01
  HostName hpct01.op.umcutrecht.nl
  User wvanburen 
  Port 22
  Protocol 2

# usage : ssh hpct02
Host hpct02
  HostName hpct02.op.umcutrecht.nl
  User wvanburen 
  Port 22
  Protocol 2

# usage : ssh ft_gw2hpct01
#         then start a filezilla session on localhost
# for filetransfer from hpct01 to local machine
Host ft_gw2hpct01
  HostName hpct01.op.umcutrecht.nl
  User wvanburen 
  Protocol 2
  ProxyCommand ssh -X -i ~/.ssh/id_rsa_hpc -L 8888:hpct01.op.umcutrecht.nl:22 -l wvanburen hpcgw.op.umcutrecht.nl nc %h %p 2>/dev/null

# usage : ssh ft_gw2hpct02
#         then start a filezilla session on localhost
# for filetransfer from hpct01 to local machine
Host ft_gw2hpct02
  HostName hpct02.op.umcutrecht.nl
  User wvanburen 
  Protocol 2
  ProxyCommand ssh -X -i ~/.ssh/id_rsa_hpc -L 8888:hpct02.op.umcutrecht.nl:22 -l wvanburen hpcgw.op.umcutrecht.nl nc %h %p 2>/dev/null
#########################################

With this oneliner you can replace wvanburen in your own username int the file "~/.ssh/config"

sed -i 's/wvanburen/my_username/' ~/.ssh/config 

Try

ssh gw2hpcs04 

It will ask for your passphrase on the gateway hpcgw followed by your hpc-password on hpcs04 .

-- Rene Janssen - 2020-03-27