Remote Access

Accessing From Linux

Using jump host and SSH ProxyJump

To access an individual instance via a jump host/bastion server, the ProxyJump option (-J) of the SSH client can be used. This feature was introduced in SSH 7.3.

To use it, provide the username and hostname of the jump host as an argument to the -J parameter followed by the username and hostname of the target instance:

ssh -J user@jump.host user@target.host

To get more detail how a bastion is set up within a cloud project, check the example scripted in Terraform.

Setting Up VPN Tunnel Via Encrypted SSH With sshuttle

# terminal A
# Launch tunnel through jump-host VM
 
# Install sshuttle
if grep -qE 'ID_LIKE=.*debian' /etc/os-release; then
  # on debian like OS
  sudo apt-get update
  sudo apt-get -y install sshuttle
elif grep -qE 'ID_LIKE=.*rhel' /etc/os-release; then
  # on RHEL like systems
  sudo yum -y install sshuttle
fi
 
# Establish the SSH tunnel (and stay connected) where
# 147.251.21.72 is IP address of example jump-host
# 172.16.0.0/22 is IP subnet where example cloud resources are available
sshuttle -r centos@147.251.21.72 172.16.0.0/22

Accessing (Hidden) Project VMs Through VPN Tunnel

# terminal B
# Access all VMs allocated in the project in 172.16.0.0/22 subnet
$ ssh debian@172.16.0.158 uname -a
Linux freznicek-deb10 4.19.0-14-cloud-amd64
 
# Access is not limited to any protocol, you may access all services.
$ curl 172.16.1.67:8080
Hello, world, cnt=1, hostname=freznicek-ubu

Accessing From Windows

PuTTY is a client program for the SSH on Windows OS.

PuTTY Installer

We recommend downloading Windows Installer with PuTTY utilities as:

• Pageant (SSH authentication agent) - store the private key in memory without the need to retype a passphrase on every login
• PuTTYgen (PuTTY key generator) - convert OpenSSH format of id_rsa to PuTTY ppk private key and so on

Connect to Instance

• Run PuTTY and enter Host name in format “login@Floating IP address” where login is for example debian for Debian OS and Floating IP is IP address to access instance from internet.
• In Category -> Connection -> SSH -> Auth:
  • Select Attempt authentication using Pageant
  • Select Allow agent forwarding
  • Browse and select your private key file (convert OpenSSH format id_rsa to Putty ppk)
• Return to Session page and Save selected configuration with Save button
• Now you can log in using Open button
• Enter passphrase for selected private key file if Pageant SSH authentication agent is not used
  • We recommend using Pageant SSH Agent to store the private key in memory without the need to retype a passphrase on every login

Pageant SSH Agent

• Run Pageant from Windows menu
• Locate Pageant icon in the Notification Area and double click on it
• Use Add Key button
• Browse files and select your PuTTY Private Key File in format .ppk
• Use Open button
• Enter the passphrase and confirm OK button
• Your private key is now located in the memory without the need to retype a passphrase on every login

Key Generator

PuTTYgen is the PuTTY key generator. You can load in an existing private key and change your passphrase or generate a new public/private key pair or convert to/from OpenSSH/PuTTY ppk formats.

Convert OpenSSH Format to PuTTY ppk Format

• Run PuTTYgen, in the menu Conversion -> Import key browse and load your OpenSSH format id_rsa private key using your passphrase
• Save PuTTY ppk private key using button Save private key, browse destination for PuTTY format id_rsa.ppk, and save file

Convert PuTTY ppk Private Key to OpenSSH Format

• Run PuTTYgen, in the menu File -> Load private key browse and open your private key in format PuTTY ppk using your passphrase
• In the menu Conversion -> Export OpenSSH key browse destination for OpenSSH format id_rsa and save file

Change Password for Existing Private Key Pair

• Load your existing private key using button Load, confirm opening using your passphrase
• Enter a new passphrase in the field Key passphrase and confirm again in the field Confirm passphrase
• Save changes using button Save private key

Generate New Key Pair

• Start with Generate button
• Generate some randomness by moving your mouse over the dialog
• Wait while the key is generated
• Enter a comment for your key using “your-email@address”
• Enter a key passphrase, confirm the key passphrase
• Save your new private key in the id_rsa.ppk format using the Save private key button
• Save the public key with the Save public key button