THE COURSE OVERVIEW:
OS Linux is a special piece of Software running on your system to make it possible start and stop your program like work or Excel. Besides that it handles input and ouput for you and delivers file system hardware control. Examples of OS you may know Windows, MacOS, Android /IOS.Linux is not a specific or full working OS but implements the essentials in a go of it which is called kernel. Most type of Linux OS donot cost anything but provides thousands of programs and softwares in free of charge. Most of these programs are also open source which means you can view the exact blue print of the program has been created and can be changed by anyone.
One very important area where Linux is very popular and used heavenly are managing many network services.These are programs that runs in the background of any UNIX server continuously, waiting for external events to responsond continuously with some kind of action or information.Examples of popular internet services such as web server which presents websites to the user, mail server for email communications and Data servers to store and deliver the data.As said before linux is only the name of the kernel path and not full working OS, to make it complete you need to bundle it with kinds of programs which is thus refer to as distributions.There are pros and cons for all distributions, the main difference is the software selected and bundled together with linux kernel.
The most important linux family is REDHAT based and tech based linux distributions.CENTOS 7 is one of the most important REDHAT Based free linux server distribution all there at the moment. Its very stable,securable and reliable OS which is widely used in running very critical network services in enterprises environments. Also the development of this are very strong and updates are well selected and properly tested.
We are having 5 sections, In section1 we will be introducing you to the concept of Installation.Then we will be creating freecentos vitual machines called VM through software called Virtual Box.We will set ssh for forwarding so you can conviniently communicate between your main OS and your CENTOS VM installation.In Section 2 we will learn command lines.We will learn to navigate file system using commands, shortcut command lines and execution commands.
In Section 3 we will be learning about creating, deleting ,editing and storing files using command lines.In section 4 Working with command line, here we learn everyday work with command lines and we will introduce you to the art of shell scripting. Finally in Section 5 we will learn advance command lines.These are to show you how to update systems services ,understand how to update and install software on your system, have basics networking on your linux ,managing file systems, how you can troubleshoot errors and certificates for linux.We will end you showing what access control is all about and how they help you increasing the security of the system. Please ensure system with 64 bit ram, we will be using CENTOS 6311 which is derived from REDHAT enterprises 4113.
INTRODUCING CONCEPT OF VIRTUALIZATION:
viz the advance is the most g computer hardware such as multi purpose memory and disk space in the last 10 years. The concept of virtualization has become one more importance and useful. Virtualization is also differentiation of many new cloud technologies and is change in traditional jobs and it system administration practically. But what is actually virtualization,it is the technology to run seperate operating system parallel to main OS. For Example if you are running windows OS ,you can run mac or linux parallely in same OS.Modern virtualization Software doesnot implement to allow only one parallel OS but allows multiple OS parallely.The limits are only defined by your own computer hardware.The applications of virtualization of modern IT are endless and you will find them everywhere in cloud computing and data centers ,powerful virtualization server clusters are running many different OS simultaneously, instead of using dedicating server hardware. If you want to use linux before the age of virtualization, you need to access to dedicated physical computers , also mouse, VPCs, and we miss new linux installation,several times installing out of linux. Often times subsequent changes are hard to reboot and the only useful and efficient concequence is to reinstall complete system when getting stuck.
virtualization get rid of complete problem, we will work for conviniently working with all the exams throughout.Thanks to its powerful features such as cloudening ,taking snapshots or creating images which also elminates the fear of braking something. At the moment there is a broad range of different virtualization products available for bounce test of non-graphical server environment to choose from also the compasonate sourcing tool. Os running parallely in as system is refered to as VM. Our main OS running on VM which runs virtualization software on the physical machine is called the host system or Hypervisor. The virtual machine running on the host is the guest, copying and cloning is one of the most important feature of Virtualization.
If you need another technical machine or graph more audible just copy the image to your left top on different data center and you are done. The partible copy of VM is an image and the awesome feature is taking snapshot of your VM. Taking such snapshots will only take few seconds. But will take the complete state of VM at given point in time. This is very useful if you want to preserve giving version for your VM, you may later what to revert back to. The different modes of VM that connects to network can be
1.NAT:
All the incoming and outgoing Network traffic is VM will go through the networking adapter, which means the VM is not visible in an network and we only see our host naked IP address.
2.BRIDGED:
This network node exposes VM itself and connects itself to the connecting to surrounding physical network as it could be a normal physical machine with its own unique mac address. The Http server will give its own ip address for the server different from the host ip difference from host machine ,
3.HOST ONLY:
host only network, means that VM only communicate with and visible to its host and not with the rest of the network,
4. VIRTUAL NETWORK:
specific virtual netwoek and here we can find private and associated network address independent of the surrounding physical network.This can be very useful because only VM can see and talk to other machine within the network.
INSTALLING OF CENTOS IN VIRTUALBOX:
Open "www.virtualbox.org" in browser then click and download in specified target path, it this example we will use windows, Click and Download windows Virtual Box also Download the Virtual Box Extension Path.After Downloaded install it and run it.Now lets Create Centos Virtual box,we need to download minimal centOS ISO5 V611 from the official centOS website it contains most important software packages needed to run non graphical linux server.Open www.centos.org then click on get CentOS now, then click on minimal ISO tab then in next page Download URL based on location.
Download install and Open CentOS Virtual Box, once centos Virtal Box UI is opened click new and name as"Cent OS 7 Server", click next now choose how much Memory/ram required for VM.If you dont want any performance issues for your host systems please change the green area to display to you window for basic headless which means the non graphical server atleast need up a framework are recommended ,we can also change later.Click on the next button on next screen leave everything as it is and click on create and the next screen stay with the selected VDI option then click next and stay with dynamically allocated option, click on next. In the next screen double the hard disk to 60 GiB where as 8 GiB is too small, finally click create to get free empty VM, ready for installation centOS 7.
Now to create Cento7 VM click on empty VM created with config and click green start button, here insert our downloaded centO7 OS ISO which we will use to see the robo virtual box.Click on the folder symbol and choose the downloaded CentOS 7 minimal ISO.Then click on start button. Now your VM will provide you desktop menu use up arrow to choose install CentOS Linux and then press enter to start installation.After waiting for some time you will get the graphical Installation screen, we need to know how we can switch back to the host system. IF you click once inside guest window you will get a pop up window showing how you can switch back and forth.
Please read the information box carefully and donot skip any information. First choose the installation language default English, Choose continue.Now we are the main installation screen please wait for the all items to get loaded.Items with exclamation mark need to be done before installation likr setting your location information.Next we need to select installation and destination ,we need to provide full harddisk for installation as we use emtpy VM i.e 34 so just click on that. before installation we need to enable our network RDM, so we dont need to use command line for installation. It uses host internet, so make sure your internet is ready if you are using proxy please mention it here.Then click on bgin installation,while installing please suggest strong password, which the account uses for writing in the system and click done.
Here you can create Normal user account for everyday work.and click done if ready.Wait for installation to get finished. If the installation is done click on finish installation button to restart your system.press enter in the screen menu to get latest kernel. Now wait until you get login screen which is also called our servers terminal. Login using root user and password you set during installation.then in cursor type yaml update -y and type return key,which is a command.This command with update all latest softwares for your server.If you get UIL error while running command something wrong in internet connection and need to check connection.
IF the core of the system is updated we need to reboot the system.Type reboot and press return key.after returning press return key again to get the login screen and login again.Next we clear out all free space,we can create a backup of system. type
dd if =/dev/zero of=/dd.img; rm -f /dd.img then click return button. This text of command will overwrite all the free space by creating one big file containing zero until the disc is full.we will get text and error which is expected.
For setting up ssh ,we need to write down all the IP address of VM connected Network adapter. Type "ip addr list" press return key.In the output line please write down the IP address which the value of our Inet. For turning OFF the VM we should use "shutdown -h now press return key. wait for shutdown.
HOE TO WORK WITH VIRTUALBOX:
The most setting can directly translated from virtualbox to any other virtualization software such as kvn ,vmware workstation or parallel desktop. To start with import appliance go to File and click import appliance, which lets you to reimport image files. Once image is created export. In the upcoming screen select the VM you want to create.On next tab leave everything as it is and click next.
Comments
Post a Comment