Using SSH agent to login on remote clusters
===========================================

::

    $ ssh-keygen -t rsa -b 4096 -f ~/.ssh/marconi
    Generating public/private rsa key pair.
    Enter passphrase (empty for no passphrase):
    Enter same passphrase again:
    Your identification has been saved in /home/leon/.ssh/marconi.
    Your public key has been saved in /home/leon/.ssh/marconi.pub.
    The key fingerprint is:
    SHA256:Teq9Lu4Lcw3E7IhKVfDIdpXZ1fTathq1MJktAWQ8Nl0 leon@dell5520a
    The key's randomart image is:
    +---[RSA 4096]----+
    |    ... .+o=oooE |
    |   . + +o o=.... |
    |    = o + o o.  .|
    |   o o + +    =o |
    |  . . . S .  *.oo|
    | . .   . +    =.o|
    |  .   o o o  . o |
    |       +.  .  o  |
    |       o++o  .   |
    +----[SHA256]-----+


Now we copy public key to remote machine.

    $ ssh-copy-id -i ~/.ssh/marconi g2kosl@s38.eufus.eu
    /usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/home/leon/.ssh/marconi.pub"
    The authenticity of host 's38.eufus.eu (130.186.25.38)' can't be established.
    ECDSA key fingerprint is SHA256:8bFSzd26+BVm5Bz/TufbMFqPcFghziUyYJsrXdFRwFI.
    Are you sure you want to continue connecting (yes/no)? yes
    /usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
    /usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
    g2kosl@s38.eufus.eu's password:

     Number of key(s) added: 1

     Now try logging into the machine, with:   "ssh 'g2kosl@s38.eufus.eu'"
     and check to make sure that only the key(s) you wanted were added.

.. note::

   Please note that the ``$HOME\.ssh`` directory must have the correct
   permissions. Only the user can have ``write`` permission to ``$HOME\.ssh``
   directory. To unset write permission for others write

   chmod go-w ~/.ssh

   This goes the same for ``$HOME`` directory.