Secure Shell (SSH)

Secure Shell is a cryptographic network protocol for operating network services securely over an unsecured network. Typical applications include remote command-line, login, and remote command execution, but any network service can be secured with SSH.

How to connect to your Ultra.cc slot via SSH

SSH, also known as Secure Shell, is a network protocol that gives users a secure way to access your slot remotely. With SSH, you can do the following:

All of our slot plans come with SSH access.

Please refrain from installing or running custom shell's here at Ultra.cc (zsh,eshell,fish etc) the shell currently running is customized to allow your applications and custom shell commands to function.

Changing your SSH Password

Before logging into your SSH, you should first set your own SSH/FTP password.

SSH Clients and How to Connect

OpenSSH

OpenSSH is an open-source alternative to the proprietary Secure Shell software suite offered by SSH Communications Security and is bundled with some Linux distributions and macOS. It is also an optional feature in Windows 10 since the October 2018 Update (Version 1809).

Installing OpenSSH in Windows 10

Installing OpenSSH in Linux

Some Linux distributions have OpenSSH client installed as part of their bundle. Provided below are the commands to install OpenSSH clients in some of the popular Linux distributions.

Ubuntu/Debian: sudo apt Install openssh-client

Arch Linux/Manjaro Linux: sudo pacman -Syyu openssh

Fedora: sudo dnf install -y openssh-client;

Accessing slot’s Terminal via OpenSSH

The following screenshots are from Windows' command prompt, but they should be the same on Windows, Linux, and macOS.

ssh username@IP_of_slot (your_username@123.456.789)
ssh username@servername.usbx.me (your_username@jupiter.usbx.me)
ssh username@username.servername.usbx.me (your_username@usbdocs.jupiter.usbx.me)

PuTTY

PuTTY is a free and open-source GUI SSH, Telnet, Rlogin, and serial port connection client for Windows. You may also use this to connect to your slot.

Installation

Setting up PuTTY

Termius

Installation

Setting up Termius

Termius default screen.png

Add New host highlight.png

New Host Settings.png

Ways to connect.png

Connecting to slot.png

SSH console screen.png

To read more about the Termius options in a detailed manner visit here

Public Key Authentication

SSH key pair authentication is a recommended method of logging into your slot via SSH for added security and convenience in place of our SSH password. You can place the public key on your slot, and then unlock it by connecting to it with a client that has the private key. When the two matches up, the system unlocks without the need for a password. The major advantage of this is that this authentication method provides greater cryptographic strength than long passwords, rendering it not prone to brute-force attacks. You can increase security even more by protecting your private key with a passphrase.

In this tutorial, we would be showing you on how to generate your own key pair using several tools, how to transfer your public key to your slot and how to login using key pair authentication.

OpenSSH

This should work on Linux, macOS and Windows 10 Users. If you haven't set OpenSSH up, you may refer to on how to connect to your slot via SSH for installation and setup of OpenSSH for Windows 10, Linux and MacOS.

Creating Public and Private Keys

$ ssh-keygen
Generating public/private rsa key pair.

$ ssh-keygen -b 4096
Generating public/private rsa key pair.
Enter file in which to save the key (/your_home/.ssh/id_rsa):

$ ssh-keygen -b 4096
Generating public/private rsa key pair.
Enter file in which to save the key (/your_home/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:

$ ssh-keygen -b 4096
Generating public/private rsa key pair.
Enter file in which to save the key (/your_home/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /your_home/.ssh/id_rsa.
Your public key has been saved in /your_home/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:x23Tr+Ee5TlowA+U9HEquagnog3O09EYHQ346WY xan@randomPC
The key's randomart image is:
+---[RSA 4096]----+
|=.=. . o+..      |
|.B  o  .oo.      |
|o.o  oo  o       |
|.+ . oo ...      |
| .. .  +S+ .     |
|.      =o==      |
|.o.   o.=o.      |
|o... oE.+o       |
| .. .++..o.      |
+----[SHA256]-----+

Importing Your Public Key into your slot

Now, we will import the keys you just generated to your slot. There are several methods for this and is described below.

ssh-copy-id

$ ssh-copy-id ultradocs@servername.usbx.me

$ ssh-copy-id ultradocs@servername.usbx.me
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/home/xanban/.ssh/id_rsa.pub"
The authenticity of host 'servername.usbx.me (46.182.109.120)' can't be established.
ECDSA key fingerprint is SHA256:9mQKWg1PVPZtzZ6d5nDjcWUb/Flkuq5VHYRrvwTeRTE.
Are you sure you want to continue connecting (yes/no)?

$ ssh-copy-id ultradocs@servername.usbx.me
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/home/xanban/.ssh/id_rsa.pub"
The authenticity of host 'servername.usbx.me (46.182.109.120)' can't be established.
ECDSA key fingerprint is SHA256:9mQKWg1PVPZtzZ6d5nDjcWUb/Flkuq5VHYRrvwTeRTE.
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
ultradocs@servername.usbx.me's password:

$ ssh-copy-id ultradocs@servername.usbx.me
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/home/xanban/.ssh/id_rsa.pub"
The authenticity of host 'servername.usbx.me (46.182.109.120)' can't be established.
ECDSA key fingerprint is SHA256:9mQKWg1PVPZtzZ6d5nDjcWUb/Flkuq5VHYRrvwTeRTE.
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
ultradocs@servername.usbx.me's password:

Number of key(s) added: 1

Now try logging into the machine, with: "ssh 'ultradocs@servername.usbx.me'" and check to make sure that only the key(s) you wanted were added.

Manually copying contents of your public key to your slot

This is another way is to manually copy the contents of your private key file to your slot should ssh-copy-id failed. This method works on Windows, Linux and macOS users.

 mkdir -p ~/.ssh

echo ssh-rsa AAAAB3NzaC1ycrandom_characters_here_lol xanban@randomPC >> ~/.ssh/authorized_keys

 chmod -R go= ~/.ssh

PuTTYgen

This method works for Windows users only.

Creating Key Pairs Using PuTTYgen

Importing Public Key to your slot

ultradocs@servername:~$ mkdir -p ~/.ssh

ultradocs@servername:~$ echo ssh-rsa AAAAAAAAlol rsa-key-2012-12-12 >> ~/.ssh/authorized_keys

ultradocs@servername:~$ chmod -R go= ~/.ssh

Setting PuTTY to use Key Authentication

Your Ultra.cc Shell - A Beginner's Guide

The terminal is your gateway to the inner workings of your Ultra.cc slot. It is essentially a remote computer running Linux, and when you SSH into it, you are connecting to that computer's terminal. For instructions on how to connect to your Ultra.cc slot via SSH, follow this link.

A terminal is a powerful tool where you can execute written commands to perform many simple or even very complicated tasks. This guide will help you understand a few simple commands to get you started navigating and using the Linux terminal; it can also serve as a cheat sheet later down the track if you need to recall anything you may have forgotten.

We are also keeping a curated list of pre-installed utility tools that you can use on your Ultra.cc slot. When you have familiarized yourself with the guide you are reading right now. The next step would be to check out the list of pre-installed tools, and it can be found here.

Introduction

Once you have connected to your Ultra.cc service via SSH, your terminal prompt will be placed in your home directory. This can be confirmed with the pwd command, which stands for "print working directory". By executing this command, you will see the absolute path of the current working directory, as shown below.

ultradocs@spica:~$ pwd
/home/ultradocs

However, the /home/ultradocs path is just a symbolic link. As there are multiple users on each server, and all of them require their own home directory. To see the physical home directory path of your home directory, you need to append the -P option to the pwd command. As you can see from the below output, the physical home directory path is different.

ultradocs@spica:~$ pwd -P
/home12/ultradocs

Just as in the Windows operating system where each local user have their files stored in C:/Users/username, Linux also has local users. Each user have their own individual home directory, which is /home/username where username is your Ultra.cc service username.

The absolute path of the Linux home directory is /home/username, but it can also be shortened to ~/, which can be useful when navigating the terminal. However, while editing scripts, or configuring application settings, it is always best to use the absolute path to avoid problems.

Default File/Folder Structure

In the home directory of your Ultra.cc service, there will be a set of default files and folders. Some of them are standard files that are included in every session of Bash, while some are unique to Ultra.cc. In your Ultra.cc service, the default file/folder structure would be what is stated below.

These files and folders are an integral part to keep your service functional, and should not be deleted. However, should you by mistake delete any of these files and folders, they can be restored by following the instructions in this guide.

As you can see in the above list of files and folders, some of them have a . prefixed in their name. These files are commonly known as "dotfiles" and usually serves the purpose of being important configuration files for your system. The dot signifies that a file or folder is hidden, and will therefor not show up by default when you browse the folder structure in your FTP client, or when executing the ls command. However, with ls -a, hidden files will be shown in the output.

Bash Startup Files

Whenever you are interacting with the terminal of your Ultra.cc service, you are using a shell called Bash aka Bourne Again Shell. To initialize Bash when you connect via SSH, your home directory must include a set of Bash startup files. The two most important are .bashrc and .profile. These files can be identified by having a prefixed . in their names. Below is examples of Bash files that you might find in your home directory.

Navigation

In this section, we will detail the commands used to move between directories in Linux; we will also cover how to find your location and the structure of your slot.

cd

The first thing you are going to want to do in your terminal is to navigate between directories. All tasks are performed within different directories, and your current directory affects how a command may run or how you may need to use a command.

When you first SSH into your slot, you will be in your personal home directory. This is the location of all your files; anything you wish to accomplish must be done within the home directory as this is the only folder you have read, write and execute permissions for. If, while navigating your terminal, you wish to return to your home directory, you can do so by typing cd ~.

This brings us to the command you will likely find yourself using a large amount of the time; cd. This command is used to navigate between different directories in Linux and stands for change directory. To use this command, you simply type cd followed by the directory you wish to navigate to.

In Linux, when navigating using the cd command, there are multiple ways to tell the operating system where exactly you want to be. If, for example, you want to move one directory deeper from a directory you are already in, you would use cd [directory]. If you know the directory structure already and you simply want to go to a path relative to your current location, you can use cd path/to/directory where each / stands for a directory deeper. Just like ~ refers to the home directory / refers to the root of the filesystem. If, for example, you wanted to navigate to a folder called media in your home directory, you would use the command cd ~/media.

It is also worth noting that in Linux, . refers to the current working directory and .. refers to the directory above. This is useful in if you want to go back one directory you can type cd .., or if you want to go back two you can use cd ../.. and so on.

ls

Knowing how to navigate your directories is all well and good, but how do you know where you actually want to go? For this, we use the ls command. Typing ls within any directory in Linux will instantly show you all the folders in said directory. You can also use ls to list the directories inside a different directory using ls path/to/directory.

pwd

The pwd command is used to show you the exact location you are currently in, fairly simple, really. Running pwd will print the full path to your current working directory. Very useful for when you may be lost.

File and Directory Manipulation

At some point, you are going to want to move files/directories around, copy or delete them. Here we will cover the commands involved in achieving this.

mv

The mv command stands for move; you can use it to move a file or directory to another directory. It is as simple as using the command mv [file or directory you wish to move] [where you wish to move it]. For example, if you wanted to move a directory called media to a directory called files, you would use the command mv media files. If, however, you wish to move all the files from the directory called media into the directory called files, you would use mv media/* files. This tells the operating system to move all the files (signified by /*) located in media directory.

cp

The cp command stands for copy; it is used in much the same way as mv; however, there are a few little details worth covering. The general Syntax is the same as mv; if you wish to copy a file in your current directory named Movie1.mkv to a subdirectory called media you'd used the command cp Movie1.mkv media. The difference comes when you wish to copy an entire directory, when you want to copy an entire directory, you need to tell the cp command to copy recursively. This is signified with a -r after the cp. For example, if you wished to copy the directory called media to files similar to the previous example, you'd use the command cp -r media files. Copying all the files within media to files is pretty much exactly the same; cp media/* files. However, if there are any sub-directories within media that you also wish to copy, you again need to use the -r flag; cp -r media/* files. The -r flag is used whenever you need to copy an entire directory.

rm

The rm command stands for remove, it is used to delete files or directories you no longer wish to use. It is very important to keep in mind that there is no recycling bin in Linux, any files you delete are permanently lost. Syntax for rm is much the same as cp if you wish to remove a file named Movie1.mkv you'd simply type rm Movie1.mkv. If you wish to remove an entire directory, once again, you need to use the -r flag; rm -r media would delete the entire media directory. If you wanted to remove all the files inside the media directory, you'd use rm media/* or rm -r media/* if there are directories inside the media.

unzip

The unzip command can be used to manually decompress a ZIP file via SSH terminal. The steps to unzip a file are simple, simply cd to a path where the ZIP file is located. For example, cd /path/to/location and execute unzip archive-name.zip. This will unpack the ZIP file in the current directory. Check the content using the ls command.

unrar

The unrar command can be used to manually decompress a RAR file via SSH terminal. The steps to unrar a file are simple, simply cd to a path where the RAR file is located. For example, cd /path/to/location and execute unrar x archive-name.rar. This will unpack the RAR file in the current directory. Check the content using the ls command.

For a full list of pre-installed utility tools, see this guide.

Further Info

For any commands, you need to find more information on; you can use the command man [command]. This displays a manual page for the specified command.

Ultra.cc Specific Commands

Application Management

When interacting with your slot through Secure Shell, you may wish to manipulate the applications we offer one-click installers for; to do this, you use the app-[appname] commands.

Installing and Uninstalling Apps

To install an application, we can use the command app-[appname] install. This can be helpful to gain further knowledge as to why certain installations are failing. When installing an application, you will be presented with an output in the SSH prompt showing either true or false.

Likewise, to uninstall an application, we can use the command app-[appname] uninstall. This is especially useful in the case of an application saying it's installed while not being accessible from the UCP.

Stop, Start and Restarting Apps

To change the running state of an application we use app-[appname] [start|stop|restart]. These commands will be useful for you throughout the usage of your USB slot for troubleshooting or further customize your experience.

Checking Used Space

To display your folder structure and space taken by individual files, the ncdu -x command is included in every Ultra.cc slot. After a short scan largest items are displayed top, and size is in descending order

Further Info

For further information regarding specific commands for a particular application run app-[appname] help. This will provide all sub-commands available for the said app.

SSH Troubleshooting Information

Connection Timed Out

The SSH connection will timeout after you have had multiple failed login attempts. This is a soft ban that only lasts for 10 minutes. In this case, please change your SSH password from the Control Panel and wait for 10 minutes. Then, try to log in via SSH using the newly set password. Attempting to log in even with the correct password when you are soft-banned will just get your IP banned again for 10 minutes. Therefore, it is important to wait patiently for 10 minutes.

How to check high disk IO utilization?

If your apps are slow and your slot is running sluggish, this is the most common cause.

Any file access on the disk creates IO load on the HDD, either by you or other clients on the server. This is not an issue with the NVME slots due to their incredibly high IO throughput.

Typical scenarios that cause high IO utilization:

To check the IO utilization of the disk your service is deployed on, execute the following command in your shell terminal and pay attention to the %util column.

iostat -xk 2 $(findmnt -T ~ | awk 'END {print $2}')

If the utilization is at 100% for a prolonged time, the disk is entirely saturated, which will affect the performance. We recommend reviewing the settings in your installed applications to prevent this, e.g. limiting concurrent activities by utilizing queuing when available. See the following section to find what application or process is causing high disk IO.

Check IO utilization per individual process:

If you suspect that you are the reason for the high IO utilization rather than one of your disk neighbors, you must find out which process is the culprit. There are two ways you can investigate this. The preferred way is to use htop.

See which process has the highest DISK R/W value, paying attention to whether it is B/s, K/s or M/s which is bytes, kilobytes, or megabytes per second respectively.

If the DISK R/W column is not visible in htop, you can enable it by following these instructions:

Besides using htop, you can also use pidstat to see the IO utilization per individual process. Execute the following command:

pidstat -dl 2

If the above steps do not identify any of your processes as causing high disk IO, the issue could still be your FTP activity; please check if your FTP client is downloading multiple streams and/or running without a speed limit. Failing that, another client on the same disk as you may be causing the high disk IO utilization. Please raise a support ticket if the issue continues. The support team will review all clients on the same disk as you.

How to clear up disk space or move data from my slot?

The easiest way to manage any data is by using your favorite S/FTP client. Filezilla is the most popular choice. We recommend using SFTP as your connection of choice because it is more flexible on which folders to manage. You can also drag and drop with an S/FTP client, which makes it incredibly useful as a whole. The downside of this is that it takes time for the client to process your moves. Our help guide for S/FTP is available here.

However, the fastest way is by using SSH, but this might be intimidating for inexperienced users. For starters, you can use Midnight Commander, which is a graphical user interface file manager in your slot. It can be started by executing mc in your shell. You can also read our basic Linux cheat sheet here.

Why am I unable to connect with SSH, and why is there an error "Resource Temporarily Unavailable"?

In most cases, this is your total proclimit being saturated. We implement resource limits in each slot to ensure fair resource usage on all users. Usually, apps like rclone or syncthing are responsible due to hundreds of worker threads spawned by the application. In most cases, restarting your applications before logging into SSH again should fix the issue. If it does not work, you may need to submit a ticket.

Some of my files have duplicates in ~/files or ~/downloads directory and ~/media directory. Are they using double disk space?

If you're using Radarr/Sonarr/Sickchill/Medusa etc., they should not be taking any additional space. By default, these applications create a hardlink of the file to the default root directory of your application. A hard link can be described as a single file located at two different paths but pointing at the same block of data on the disk. Think of it as two signposts from other streets that direct you to the same destination. Hardlinks do not take any extra space. You can compare the inode numbers for both files from the Terminal (SSH Access) with ls -I on both files'. The inode number will be the same.

You can read more about Hard Links here: https://en.wikipedia.org/wiki/Hardlink.