In this lesson you will learn:
You'll briefly be introduced to: RHEL (RedHat Enterprise Linux), Fedora, CentOS, AlmaLinux, Rocky Linux, Ubuntu, Debian, OpenSuse and SLES (SuSE Linux Enterprise Server).
In this lesson, you will learn:
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What is Linux Distribution or Linux Distro is
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What the most common Linux Distro are
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How to choose the right Linux Ditro
Specifically, you'll learn about the most popular Linux Distros including RHEL (RedHat Enterprise Linux), AlmaLinux, Rocky Linux, CentOS and Ubuntu.
Other Distros are mentioned, such as Linux Mint, Debian, Magento, OpenSUSE, Popl_OS, Fedora, Arch Linux, Fedora and Slackware.
In this lesson you will learn how to install, use and remove a Linux distro using Windows Subsystem for Linux ( WSL ) on Windows. You will also learn how to access the Linux files and directories using the Windows File Explorer.
In this lesson, you will learn how to install VirtualBox on Windows.
In this lesson you will learn why you need to know how to install Linux manually from scracth.
In this lesson, you will learn how to install ALmalinux 9 and RHEL ( RedHat Enterprise Linux ) 9. ( pptx 3 )
In this lesson, you will learn how to connect directly to a Linux system installed on physical hardware or inside a virtual machine. Graphical and text-based logins will be covered.
In this lesson, you will learn about the Linux directory structure. You'll learn where different components of the operating system are located. You'll also learn how application can employ the same conventions for their directory structures.
In this lesson, you will learn about the Linux directory structure. You'll learn where different components of the operating system are located. You'll also learn how application can empty the same conventions for their directory structures.
- Insert the installation disc into the DVD drive and restart the computer. Then the language selection screen will be displayed as shown below, so select the language you want to use. In this example, we will proceed in English.
- Select a keyboard layout. You can use the tab key to switch between items, the Enter key to display the list, and the arrow keys to select.
- Select the Ubuntu server configuration you want to install. The upper row is a general server configuration that includes frequently used software, and the lower row is the minimum server set.
- This is the item for network connections. If there is a DHCP server running in the local network, it will be obtained automatically, so you can proceed as it is.
- If necessary, enter the address of the proxy server. If you don't need it, you can leave it blank.
- Enter the address of the mirror server that you want to refer to when updating the Ubuntu server or installing new packages. Normally, the source location automatically selects a nearby mirror server, so you can continue.
- Storage settings. Set the partition layout of the disk and so on. If you don't have any special requirements, you can just proceed
- This is the screen to confirm the storage settings. If it's OK, choose Done to continue.
- It is a confirmation that you can proceed with the installation. If there is existing data on the disk, it will be overwritten, and so on. If you're satisfied, click Continue.
- This is the setting of the user account that will be the administrator. Enter a name and password of your choice and proceed to the next step.
- You have the choice to install an SSH server. Please select according to your needs. In this example, we will proceed without making a selection.
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A selection of applications and environment sets that are commonly used for server applications. Please select according to your needs. In this example, we proceed without selecting anything.
- When the installation is complete, the following screen will appear. Choose Reboot Now to finish.
- After the installation is complete, reboot and the login screen will be displayed as shown below. Authenticate and log in with the user and password you set during installation. This completes the installation of Ubuntu Server.
Adding a user
adduser userEnter password for newuser
Granting a User Sudo Privileges
groups userAdd newuser as ROOT / NON_ROOT
usermod -aG sudo userEnter newuser as NORMAL USER
ssh user@<server ip address>Enter newuser as ROOT
sudo su user
The SSH protocol (also referred to as Secure Shell) is a method for secure remote login from one computer to another. It provides several alternative options for strong authentication, and it protects communications security and integrity with strong encryption. It is a secure alternative to the non-protected login protocols (such as telnet, rlogin) and insecure file transfer methods (such as FTP).
Note
Port 22 - SSH
Using Putty or Linux Terminal
ssh username@ip address
Enter password
Sudo is a program for Unix-like computer operating systems that enables users to run programs with the security privileges of another user, by default the superuser. It originally stood for "superuser do", as that was all it did, and this remains its most common usage; however, the official Sudo project page lists it as "su 'do'". The current Linux manual pages for su define it as "substitute user", making the correct meaning of sudo "substitute user, do", because sudo can run a command as other users as well.
If on Root User,
passwdIf Normal User,
sudo passwdEnter new password
Note
Must update and upgrade server every login to make sure security update
sudo apt updatesudo apt upgradesudo apt update && sudo apt upgrade -yNote
-y will allow auto install upgrade and mean Yes
sudo reboot
What is SwapFile?
Swap is a portion of hard drive storage that has been set aside for the operating system to temporarily store data that it can no longer hold in RAM. This lets you increase the amount of information that your server can keep in its working memory, with some caveats. The swap space on the hard drive will be used mainly when there is no longer sufficient space in RAM to hold in-use application data.
The information written to disk will be significantly slower than information kept in RAM, but the operating system will prefer to keep running application data in memory and use swap for the older data. Overall, having swap space as a fallback for when your system’s RAM is depleted can be a good safety net against out-of-memory exceptions on systems with non-SSD storage available.
Before we begin, we can check if the system already has some swap space available. It is possible to have multiple swap files or swap partitions, but generally one should be enough.
We can see if the system has any configured swap by typing:
sudo swapon --showIf you don’t get back any output, this means your system does not have swap space available currently.
You can verify that there is no active swap using the free utility:
free -hAs you can see in the Swap row of the output, no swap is active on the system.
Before we create our swap file, we’ll check our current disk usage to make sure we have enough space. Do this by entering:
df -hThe device with / in the Mounted on column is our disk in this case. We have plenty of space available in this example (only 1.4G used). Your usage will probably be different.
Although there are many opinions about the appropriate size of a swap space, it really depends on your personal preferences and your application requirements. Generally, an amount equal to or double the amount of RAM on your system is a good starting point. Another good rule of thumb is that anything over 4G of swap is probably unnecessary if you are just using it as a RAM fallback.
Now that we know our available hard drive space, we can create a swap file on our filesystem. We will allocate a file of the size that we want called swapfile in our root (/) directory.
The best way of creating a swap file is with the fallocate program. This command instantly creates a file of the specified size.
Since the server in our example has 1G of RAM, we will create a 1G file in this guide. Adjust this to meet the needs of your own server:
Important
Disable running swapfile
sudo swapoff -aCreating swapfile
sudo fallocate -l 4G /swapfileWe can verify that the correct amount of space was reserved by typing:
ls -lh /swapfileOur file has been created with the correct amount of space set aside.
Now that we have a file of the correct size available, we need to actually turn this into swap space.
First, we need to lock down the permissions of the file so that only users with root privileges can read the contents. This prevents normal users from being able to access the file, which would have significant security implications.
Make the file only accessible to root by typing:
sudo chmod 600 /swapfileVerify the permissions change by typing:
ls -lh /swapfileAs you can see, only the root user has the read and write flags enabled.
We can now mark the file as swap space by typing:
sudo mkswap /swapfileAfter marking the file, we can enable the swap file, allowing our system to start using it:
sudo swapon /swapfileVerify that the swap is available by typing:
sudo swapon --showWe can check the output of the free utility again to corroborate our findings:
free -hOur swap has been set up successfully and our operating system will begin to use it as necessary.
Our recent changes have enabled the swap file for the current session. However, if we reboot, the server will not retain the swap settings automatically. We can change this by adding the swap file to our /etc/fstab file.
Back up the /etc/fstab file in case anything goes wrong:
sudo cp /etc/fstab /etc/fstab.bakAdd the swap file information to the end of your /etc/fstab file by typing:
echo '/swapfile none swap sw 0 0' | sudo tee -a /etc/fstabNext we’ll review some settings we can update to tune our swap space
There are a few options that you can configure that will have an impact on your system’s performance when dealing with swap.
The swappiness parameter configures how often your system swaps data out of RAM to the swap space. This is a value between 0 and 100 that represents a percentage.
With values close to zero, the kernel will not swap data to the disk unless absolutely necessary. Remember, interactions with the swap file are “expensive” in that they take a lot longer than interactions with RAM and they can cause a significant reduction in performance. Telling the system not to rely on the swap much will generally make your system faster.
Values that are closer to 100 will try to put more data into swap in an effort to keep more RAM space free. Depending on your applications’ memory profile or what you are using your server for, this might be better in some cases.
We can see the current swappiness value by typing:
cat /proc/sys/vm/swappinessFor a Desktop, a swappiness setting of 60 is not a bad value. For a server, you might want to move it closer to 0.
We can set the swappiness to a different value by using the sysctl command.
For instance, to set the swappiness to 10, we could type:
sudo sysctl vm.swappiness=10This setting will persist until the next reboot. We can set this value automatically at restart by adding the line to our /etc/sysctl.conf file
sudo nano /etc/sysctl.confAt the bottom, you can add:
vm.swappiness=10
Save and close the file when you are finished.
Another related value that you might want to modify is the vfs_cache_pressure. This setting configures how much the system will choose to cache inode and dentry information over other data.
Basically, this is access data about the filesystem. This is generally very costly to look up and very frequently requested, so it’s an excellent thing for your system to cache. You can see the current value by querying the proc filesystem again:
cat /proc/sys/vm/vfs_cache_pressureAs it is currently configured, our system removes inode information from the cache too quickly. We can set this to a more conservative setting like 50 by typing:
sudo sysctl vm.vfs_cache_pressure=50Again, this is only valid for our current session. We can change that by adding it to our configuration file like we did with our swappiness setting:
sudo nano /etc/sysctl.confAt the bottom, add the line that specifies your new value:
vm.vfs_cache_pressure=50
Save and close the file when you are finished.
Following the steps in this guide will give you some breathing room in cases that would otherwise lead to out-of-memory exceptions. Swap space can be incredibly useful in avoiding some of these common problems.
If you are running into OOM (out of memory) errors, or if you find that your system is unable to use the applications you need, the best solution is to optimize your application configurations or upgrade your server.
Remote Desktop Protocol (RDP) is a network protocol developed by Microsoft that allows users to remotely access and interact with the graphical user interface of a remote Windows server. RDP works on the client-server model, where an RDP client is installed on a local machine, and an RDP server is installed on the remote server.
RDP is widely used for Windows remote connections, but you can also access and interact with the graphical user interface of a remote Linux server by using a tool like xrdp, an open-source implementation of the RDP server.
In this tutorial, you will install and configure an RDP server using xrdp on a Ubuntu 22.04 server and access it using an RDP client from your local machine. You will understand how to establish access to a remote Linux server by configuring and using an RDP connection.
In this step, you will install and configure a desktop environment on your Ubuntu server. By default, an Ubuntu server comes with a terminal environment only. A desktop environment will need to be installed to access a user interface.
From the available options for Ubuntu, you will install the Xfce desktop environment. Xfce offers a lightweight, user-friendly desktop environment for Linux-based systems.
To begin, connect to your server using SSH and update the list of available packages using the following command:
sudo apt updateNext, install the xfce and xfce-goodies packages on your server:
sudo apt install xfce4 xfce4-goodies -yYou will be prompted to choose a display manager, which is a program that manages graphical login mechanisms and user sessions. You can select any option from the list of available display managers, but this tutorial will use gdm3.
After installing the desktop environment, you will now install xrdp on your server.
xrdp is an open-source implementation of the RDP server that allows RDP connections for Linux-based servers. In this step, you will install the xrdp on your Ubuntu server.
To install xrdp, run the following command in the terminal:
sudo apt install xrdp -yAfter installing xrdp, verify the status of xrdp using systemctl:
sudo systemctl status xrdpThis command will show the status as active (running):
If the status of xrdp is not running, you may have to start the service manually with this command:
sudo systemctl start xrdpAfter executing the above command, verify the status again to ensure xrdp is in a running state.
You have now installed xrdp on your server. Next, you will review the xrdp configuration to accept connections from remote clients.
In this step, you will review the default configuration of xrdp, which is stored under /etc/xrdp/xrdp.ini, and add a configuration for an RDP connection. You will also update the firewall settings.
xrdp.ini is the default configuration file to set up RDP connections to the xrdp server. The configuration file can be modified and customized to meet the RDP connection requirements.
Open the file in nano text editor or any editor of your choice:
sudo nano /etc/xrdp/xrdp.iniThe configuration file contains different sections:
- Globals defines some global configuration settings for xrdp.
- Logging defines logging subsystem parameters for logs.
- Channels defines multiple channel parameters that RDP supports.
- Session types defines multiple supported session types by xrdp. Every session type configuration is defined as a separate section under its session type name enclosed in square brackets, such as [Xorg] and [XVnc]. There is no [Sessions types] heading in the file; instead, it is written as a comment.
In the configuration file, navigate to the Session types section. You will find multiple supported session types and their parameters listed:
By default, the username and password parameters are set to ask, which means the user will be prompted to enter their username and password to connect over RDP. Parameters, such as name, username, and password. can be modified if necessary. For the initial RDP connection to the server, the default configuration will suffice.
Save and close the file when finished.
Now move to your user’s home directory if you are not there already:
cd ~Next, you will create a .xsession file under /home/sammy and add the xfce4-session as the session manager to use upon login:
echo "xfce4-session" | tee .xsessiontee writes the echoed string "xfce4-session" to the file .xsession. The above configuration ensures that xfce4-session is used as a session manager upon graphical login request. As a result of installing xfce as your desktop environment, xfce4-session serves as its session manager. If you don’t include this information in the .xsession file, no session manager is chosen, and the RDP session will fail to connect to the graphical display.
Restart the xrdp server:
sudo systemctl restart xrdpIn this step, you will test the RDP connection from your local machine. The sections below include actions for testing the connection on Windows, macOS, and Linux machines.
To test the connection using the Remote Desktop Connection client on Windows, first launch the Remote Desktop Connection app.
Enter your remote server’s public IP and username into the fillable text boxes for Computer and User name. You may need to press the down arrow for Show Options to input the username:
Press the Connect button. If you receive an alert that the Remote Desktop can't connect to the remote computer, check that you have turned on the Remote Desktop option in your system settings.
Press Yes if you receive the identity verification popup:
Then, enter your remote server’s username (sammy) and the password you created for user sammy during the initial server setup. Press Ok.
Once you have logged in, you should be able to access your Ubuntu Desktop environment:
Using RDP, you successfully connected to your remote Ubuntu server from your local machine. You can close it with the exit button when you have finished using your graphical desktop.
cd <to file directories>sudo nano <<filename>sudo touch <filename>sudo mkdir <foldername>sudo rm -rf <filename>
UFW (uncomplicated firewall) is a firewall configuration tool that runs on top of iptables, included by default within Ubuntu distributions. It provides a streamlined interface for configuring common firewall use cases via the command line.
This cheat sheet-style guide provides a quick reference to common UFW use cases and commands, including examples of how to allow and block services by port, network interface, and source IP address.
Verify the status of your UFW firewall:
sudo ufw statusDisable UFW Firewall
sudo ufw disableEnable UFW Firewall
sudo ufw enableAllow SSH
sudo ufw allow sshOr can be use,
sudo ufw allow 22Allow http
sudo ufw allow httpOr can be use,
sudo ufw allow 80Allow https
sudo ufw allow httpsOr can be use,
sudo allow 443Allow RDP
sudo ufw allow 3389Block Ip Address
sudo ufw deny from <ip address>Allow Ip Address
sudo ufw allow from <ip address>UFW Status Numbered
sudo ufw status numberedUFW Delete Numbered
sudo ufw delete <numbered>Allow Connection From Ip Address to Specific Port
sudo ufw allow from <ip address> to any port <port numbered>UFW MANUAL
sudo man ufwThe simplest form of the ping command is by following the syntax: ping [options] destination. Below are examples to get you started:
ping <ip address>This command will ping the device with the IP address and display the results.
ping <hostname.com>Similarly, you can ping by hostname which will resolve to an IP and perform the ping to that IP.
sudo apt install virt-managersudo reboot
sudo install htopsudo htop
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