[MUSIC] All right, so I'll switch gears now to look at setting up to use the graphical user interface on Linux. And you'll find times that administration is easier using a built in Linux graphical tool, say or in applications administration must be done or is more easily done using a graphic tool so providing the data center supports. It's used the virtual network computing tool or VNC is the most popular way for administrators to gain graphical access to a Linux system. Now, this provides a remote desktop on the Linux system. These days the VNC server is installed separately after the initial system installation is done or smartly, it's installed as part of a bundle with the Linux operating system. So you may find it already installed we'll talk later about how to install it. The most popular VNC packages, and there are a number of them are TigerVNC and RealVNC. And the reason I mention them is because both provide support for Windows, macOS, and Linux operating systems, so a lot of flexibility and access there RealVNC supports Unix operating systems as well like Aix, HP-UX and Celeris. An interesting is included with the default Raspberry Pi operating system raspbian. All right, but for now, let's leave this alone. I'll be covering software installation later in the module. Let's talk more about VNC. So how does it work? Well, VNC uses a protocol called remote frame buffer to efficiently transfer frames of graphical images from a server system to a client. Now, the client is often referred to as the viewer system, so this is a client server protocol. You setup VNC on the server. This is the server on which you want to gain GUI access, and you install a viewer on the client system from which you want to gain access. VNC is based on ports, as you would imagine. It's network based, so any firewalls between the client and the server must be configured to allow the ports configured for VNC's use. Now, by default VNC uses ports 5,900 plus display numbers for each user added to 5,900. So for example, a user setup to use display number four would require port 5,904 to be open as well. Now, the port numbers can be changed if the administrator desires in a configuration file, and this is done differently depending on the VNC server package that's being used, all right? So let's get a little bit more detail. Once the VNC server packages installed, some configuration is required, the configuration boils down to basically four steps. The first one copy and update the sample configuration file, possibly more than one. If multiple users need unique VNC access, take the firewall rule VNC server traffic to flow. You said a VNC password for each user that will be using VNC and then you start the VNC server for each user that will be using VNC. Now, optionally, you can set the VNC server's service to start at reboot, and that's a pretty good idea. The configuration file steps are reflected on the screen. Now, take time to review these commands and take note that the exact start command is quite a bit different. Than what you'll see in the sample configuration file. This is taken from RHEL 7, where the syntax that's the sample syntax actually fails. I've pointed out the syntax that works on the screen. Now, the firewall in VNC server commands are reflected on the screen now and take even a little bit more time to review these commands. Notice I'm missing the VNC password setting. It's simple type the command VNC password, then type the password twice. Also, notice that I supplied a couple of extra bonus commands that will be useful as you use VNC. Okay so, to use VNC the previous stuff was setting up to use VNC, launched the viewer, and when prompted, supply the server's address in the display number that you've been assigned. Now, you obviously have installed the VNC viewer prior to this on whatever platform you're running the viewer from. Then you enter the VNC displays password and this should take you to the Linux Systems Desktop. Now, if the desktop session is not already logged in, you'll have to log into the session using a valid Linux user ID and password combination. Talked about that in previous videos. And now, with VNC configured and started the Linux desktop that is installed and started with the with VNC can vary. I'm going to display a couple of graphics that give you a feel for what you can expect. So what you see here is an example of the Gnome Desktop. You'll see the upper left hand corner contains links to menus for a couple of categories, applications and places. Applications is the place to start. Here, you'll find configuration tools, web browsers, office tools like a spreadsheet presentation app. As well as tools to manage the software in the system. Now, since I'm not going to focus on GUI management of Linux on power, I'll skip the details, but I found that the tools are rather intuitive and they're pretty easy to figure out. Also, note that what you see on the screen may vary depending on what packages have been installed, either during the installation of the operating system or after the install of the operating system was complete. Now, one of the GUI tools of particular interest that I'll highlight though before I wrap up this system. Wrap up is the system monitor what administrator hasn't been faced with the question of poor performance and needed to figure out what process or processes are using most of the systems resources. As you can see in my examples, there isn't a lot of system utilization at the time they were captured, but you can imagine seeing processes in the table with high processor or memory utilization and those would be the ones to focus on in a crisis moment. All right, so that wraps up my lesson on VNC. And graphical access to Linux. If you need more information. I'll be honest, there's plenty of very good supplemental documentation for, say, TigerVNC and the Gnome Desktop on Red Hat's support page. Very intuitive stuff.
