Use local dev tools on remote files with SSHFS

TJ Kolleh — Sat, 14 Nov 2020 03:31:22 +0000

I often have to work with virtual machines or remote hosts. To utilize my local development environment while doing so I configure SSH and SSHFS. Enabling the use of tools on the local host while working with files on the remote, with the security of ssh.

SSHFS (SSH filesystem) enables the mounting of a remote directory over a normal ssh connection to the local filesystem. Prior to installing, make sure SSH is setup with the appropriate keys.

Download & Install FUSE for macOS
Download & Install SSHFS

Mount remote filesystems

The following command mounts the remote directory to a specified mount point.

sshfs username@remotesystem:/remote/path/to/directory ~/mount/point

The rmount and rumount bash scripts facilitate convenient mount and unmounts using sshfs. To begin using the scripts.

Create a folder named mounts in your user home directory, ~/mounts.
Download the scripts and make them executable, chmod u+x <path-to-script>.

The functions reference host named in the local ~/.ssh/config file, configured with a key pair (without a password). See earlier blog post on the subject for reference.

Host ml
  HostName ec2-*.compute-1.amazonaws.com
  User ubuntu
  PreferredAuthentications publickey
  IdentitiesOnly yes
  IdentityFile ~/.ssh/aws
  Port 22

Executing rmount ml - will mount the entire filesystem to a local ml (~/mounts/ml) folder. A folder created by the function. The default "mounts" path, created earlier, can be changed by modifying the function. Executing rmount ml:/home/ec2-user mounts the ec2-user directory in ~/mounts/ml/. Running rumount ml, removes the ml folder and unmounts the remote filesystem.

With a remote filesystem mounted locally, local development tools can be used without having to download each file or having to remember to sync files. Its a secure tunnel to your remote filesystem where files behave almost as if they're local.

I'm publishing this as part of 100 Days To Offload. You can learn more by visiting #100DaysToOffload.

Original post...

SSH To Guest or Remote OS

TJ Kolleh — Wed, 22 Apr 2020 17:17:10 +0000

I often have to work with virtual machines and/or remote servers. When its more convenient to use local developer tools, I rely on SSH and SSHFS. This post describes how to setup SSH to connect to a Ubuntu VirtualBox VM. The information can also be applied to other remotes hosts. Connecting to a remote OS via SSH is the first step in extending the use of your local tools for remote development. A subsequent blog post describes how to configure SSHFS.

Setup Virtual Box
Communicate with the guest OS (SSH)
Login with SSH keys

Setup Virtual Box

Download and install VirtualBox to the host operating system (host OS). Create or import a new virtual machine with your preferred OS. For this post, Ubuntu OS (guest OS) will be running inside of Oracle VirtualBox.

Communicate with the guest OS (SSH)

SSH provides secure login to remote machines over a network, and more. From the VirtualBox Manager start the Ubuntu VM (graphically) and open the terminal application in Ubuntu.

Install the OpenSSH daemon/server (sshd) with the command sudo apt-get install openssh-server. Then run the following commands to - enable SSH, start the SSH daemon, and check it's status.

Check the Ubuntu OS version per the output of the cat /etc/*release* command.

Ubuntu version 16.04 LTS or newer

sudo systemctl enable ssh
sudo systemctl start ssh
sudo systemctl status ssh

Ubuntu versions 14.04.4 LTS

sudo service ssh start
sudo service ssh status

Allow SSH through the Ubuntu firewall (ufw), if active. Check firewall status with the command sudo ufw status. Allow SSH through the firewall (port 22) using the command sudo ufw allow ssh.

To find the guest OS on the network we can use its IP address or use port forwarding to send all traffic from host to guest via a designated port.

Connect via port forwarding

Select settings from the VirtualBox manager then network -> advanced -> port forwarding.

Add a new port forwarding rule that maps host OS port 2222 to guest OS port 22 such that;

Protocol: TCP
Host IP: 127.0.0.1
Host Port: 2222
Guest IP: N/A (empty)
Guest Port: 22

From the host OS - open a terminal/command prompt window and SSH to the guest OS;

ssh <guest username>@localhost -p 2222

Connect via IP address (optional)

If port forwarding doesn't work or you prefer to connect via IP address, find the guest OS IP from the output of the ifconfig command. Open the settings window, shown above, select network -> attached to -> host-only adapter save selection. Using the guest OS IP address, create a SSH connection;

ssh <guest os username>@<guest os ip>

Login with SSH keys

Copy your public key to the guest/remote host using ssh-copy-id. See references for generating a RSA key pair. To facilitate the use of scripts, don't include a passphrase while generating keys.

ssh-copy-id <remote username>@<remote ip> -i ~/.ssh/<public key>.pub

Example command for a guest OS running in VirtualBox:

ssh-copy-id ubuntu@localhost -i ~/.ssh/gen-nopass_ras.pub -p 2222

User authorization with RSA public key has been achieved. The command ssh ubuntu@localhost -p 2222 no longer prompts for a password.

References

The Secure Shell Protocol

SSH and SSH2

Ubuntu 18

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