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How to use SSH to interact with ISS-AF cluster#

Strong preference for SSH key-based authentication.

Command line: ssh -p 60000 <username>@issaf.spacescience.ro

SSH key-based authentication#

On client device (and for each client device):

  1. Generate a local SSH key 

    cd $HOME/.ssh
ssh-keygen -t ed25519 -N ''

  2. Content of $HOME/.ssh/id_ed25519.pub is either sent to admin for addition to user .ssh/authorized_keys

    OR

    the key is copied with ssh-copy-id command:
    ssh-copy-id -i ~/.ssh/id_ed25519 -p 60000 <username>@issaf.spacescience.ro

  3. Now test the passwordless authentication

SSH alias definition#

For convenience (especially for usage within IDEs and other graphical tools)
is useful to define an SSH alias within $HOME/.ssh/config file
(if absent, create with touch $HOME/.ssh/config)

Host issaf
HostName issaf.spacescience.ro
User <username>
Port 60000

Now, the alias issaf can be used in any and all programs that use libssh (rsync, sftp, scp, and various other graphical tools)

SSH default configuration#

It is useful to have some good defaults set up.
Add (and keep) as a last stanza in $HOME/.ssh/config the following: 

Host *
ControlMaster auto
ControlPath ~/.ssh/%C.sshsock
ControlPersist 600
VerifyHostKeyDNS no
CheckHostIP no
ServerAliveInterval 5
ServerAliveCountMax 10
TCPKeepAlive no
ConnectionAttempts 5
IPQoS af21 throughput
ForwardAgent yes
ForwardX11 no
ForwardX11Trusted no
ForwardX11Timeout 0
ExitOnForwardFailure yes
PreferredAuthentications publickey,password,keyboard-interactive

SSHFS - mount a remote filesystem using SFTP#

For detailed information see sshfs page

Installation#

  • For RedHat(EL) based distros : dnf install fuse-sshfs.x86_64
  • For Debian based distros : apt install sshfs

Usage#

Mounting#

With issaf alias defined previously:
sshfs issaf:</directory_on_issaf> <local_mountpoint>

Additional arguments can be set, see sshfs --help
Useful to use : 

-o compression=yes,sshfs_sync,noatime,reconnect,follow_symlinks,transform_symlinks,auto_unmount

Unmounting#

fusermount -u <local_mountpoint>