Basic NFS Installation and Configuration on Linux

Sharing files between computers and servers is an essential networking task. Thankfully, Linux’s NFS(Networked File System) makes it extremely easy. With NFS properly configured, moving files between machines is as easy as moving files around on the same machine. Since NFS functionality is built directly into the Linux kernel, it is both powerful and available on every distro, though the configuration differs slightly between them.

Setting Up The Server

Installing The Packages

Linux NFS uses the Client-Server model, so the first step in getting NFS set up is setting up the server. Because the core NFS capabilities are rooted in the kernel, there isn’t much required in the way of packages, but there are still a few regardless of the distribution as well as some configuration.
Almost all major distributions have NFS enabled, so unless you’re running a custom one, it should already be set up. The next step in getting the server set up is to install the packages.

On Ubuntu/Debian:

$ sudo apt-get install nfs-kernel-headers

On Fedora

$ sudo yum install nfs-utils system-config-nfs

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Getting The RX 480 Running With AMDGPU on Linux

AMD’s RX 480 has been out for a little over a week now, and in that week Linux gamers have been clamoring or information on whether and how the card works on their favorite distribution. Sure, Ubuntu 16.04 is officially supported by AMD’s proprietary Pro drivers, but what about everyone else, and what if you want to use those AMDGPU open source drivers that have been in the works for so long? Well, it’s definitely possible, but it’s not all that easy.

WARNING: Here be dragons, big ones. They’re pretty much the kind you’d expect to see flying around Mereen, so if you don’t want to take the chance of breaking your install and some singed eyebrows, turn back now.

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How to take and restore VM snapshot using command line on XenServer

Objective

The objective is to create a new snapshot of a XenServer virtual machine and later restore from this snapshot.

Requirements

Privileged access to XenServer’s command line.

Difficulty

EASY

Instructions

Identify VM’s UUID

First, we need to identify a VM’s UUID we wish to take a snapshot from. Use xe vm-list to list all available VM:

# xe vm-list
uuid ( RO)           : 7371124f-7d4d-66b7-cbc7-a98b1457543e
     name-label ( RW): Debian Jessie 8.5
    power-state ( RO): halted


uuid ( RO)           : bad8e456-df88-435d-ba12-3f0f6e54b2c6
     name-label ( RW): Control domain on host: xenserver
    power-state ( RO): running

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How to export/import VM to/from a backup file using command line on XenServer

Objective

The objective is to first export XenServer’s virtual machine into a regular backup file and later import a new virtual machine from the previously generated backup file.

Requirements

Privileged access to XenServer’s command line.

Difficulty

EASY

Instructions

Identify VM’s UUID

We start by identifying a virtual machine we would lake to export to as a regular backup file. Run xe vm-list to list all available virtual machines and take a note of the virtual machine in question:

# xe vm-list
uuid ( RO)           : 7371124f-7d4d-66b7-cbc7-a98b1457543e
     name-label ( RW): Debian Jessie 8.5
    power-state ( RO): halted


uuid ( RO)           : bad8e456-df88-435d-ba12-3f0f6e54b2c6
     name-label ( RW): Control domain on host: xenserver
    power-state ( RO): running

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Installing NVIDIA Drivers All Major Linux Distributions

Intro

NVIDA supports Linux with its proprietary drivers nearly as well as it does Windows. That said, it’s no secret that NVIDIA has long been the go-to choice for gaming on Linux. Unfortunately, even though the drivers support Linux well, installing them can become more complicated when dealing with different distributions. In many cases, the process is very simple but not well documented. In others, it’s a bit tougher, but there is no reason that you can’t get the latest NVIDIA drivers for your graphics card working on most major distributions.

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I2P – Anonymity for the Masses

Introduction

For many years people have wanted to protect their right to privacy. As technology changes, it seems that privacy evolves away more and more. I2P is a protocol used for an encrypted multi-proxy on the Internet. While, this sounds simple, there is actually a lot of work going on with I2P to achieve this. Unlike some multi-proxies, I2P will allow you to tunnel many more applications through it than just web browsing, making it a very robust protocol.

I2P is available for all platforms, not just Linux. For this example I have used Debian Sid to perform the installation. With the exception of ‘apt-get’, these instructions should work fine with any Linux distribution. But if you experience problems, please seek documentation for your distro.

Legal Disclaimer

As I explain this to help you maintain priviacy, there will always be a few bad apples in the crowd. I do not condone this use of this article for anything illegal. Even if you are not passing illegal information on I2P, please check your country’s laws on encryption and it’s exportation before you begin.

The Problem with Tor

One would probably see I2P as an overkill without knowing the downfalls of its predecessor. Tor was once a wonderful multi-proxy used for hiding ip addresses and bouncing off servers all over the world. At one time, it was even trusted by most governments for strong anonymity. All of that seemed to change after an article was posted in 2600 Hacker Quartley. One author exposed how becoming an exit node for Tor allowed all the traffic on the Tor network to pass right through your machine. Becoming an exit node was the same as performing a Man-In-The-Middle attack. All one had to do was open up a packet sniffer and see all the traffic going through encrypted. Tor is still used by people trying to protect their privacy. But at the same time it has become a playground for hackers and governments monitoring what they consider suspicious. I2P has secured this problem while adding more functionality.

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introduction to wine on linux

Introduction to WINE

Introduction

One of the main concerns for people making the switch to Linux is how to run the programs that they’ve become accustomed to on other operating systems, mainly Windows. For most, there are one or two programs of games that aren’t available on Linux, and that puts a major hold on adopting Linux full time. Thankfully, WINE can help to solve this problem. introduction to wine on linux

WINE is a piece of software for Unix-like systems, including Linux, OSX, and the BSDs, that allows you to run native Windows applications. WINE stands for, WINE Is Not an Emulator. That’s because it isn’t. WINE isn’t a full Windows install or some kind of VM. It is a compatibility layer that essentially translates Windows binaries. This extends to graphics libraries like DirectX 9, which is converted to OpenGL. WINE allows Linux users to run many popular Windows applications and games at similar performance to if they were running on Windows itself.

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How To backup data with rsync command under Linux

As a system administrator or just a backup-conscious home user, sooner or later (usually sooner) you will have to deal with backups. Disasters do happen, ranging from electrical storms to drive failures, and one needs to be prepared. We cannot stress enough the importance of having copies of important data. While the whole concept of backup is too long for this article, we will focus on rsync for what’s called incremental backups.

Incremental backups are based on the idea that, once you have a copy of the data you need to backup, consequent backups of the same data should be incremental, meaning that you only update the backup copy with the differences since the last operation occurred, not create another full copy. We will detail here a setup we have at home for backing up important data, but the examples here can be used at larger facilities. Once you get started, you will know what, where and when you need.

If you have a backup server that’s up 24/7, you can create a cronjob to backup your data periodically. Since our example is home-based, we have a backup server, but since it’s not up all the time, we will show you how to do it manually. rsync needs to be installed on both systems, and that’s about it, no other setup chores must be performed, at least in simple cases. Please remember that you are not by all means tied to Linux or other Unix platform : rsync is available also for Windows. If you are worried about security, rsync is working over SSH and can be regarded as a secure replacement for rcp (remote copy) command, so it’s all good.

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How to extract XZ compressed archive on Linux

XZ is another compression method used to compress data. There are several ways on how to decompress XZ archive on Linux. For a tarball XZ compressed archive first try a tar command with xf options. This way a tar command will try automatically guess a compression method. Before you run the above command firs install XZ tools:

# apt-get install xz-utils

Otherwise, you will receive error message output:

tar (child): xz: Cannot exec: No such file or directory
tar (child): Error is not recoverable: exiting now
tar: Child returned status 2
tar: Error is not recoverable: exiting now

To extract XZ tarball run:

$ tar xf myarchive.tar.xz

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How to rename VDI/Virtual disk on XenServer Linux

Objective

The Virtual Machine creation using template provisioner may spawn unnamed VDI disks. Usually, the VID description states Created by template provisioner at most.
Example:

uuid ( RO)                : 093e128a-2632-43bd-bb45-8f864bc69d6f
          name-label ( RW): 0
    name-description ( RW): Created by template provisioner
             sr-uuid ( RO): 3ef7b35b-5d39-7414-0c91-bbb281b9a521
        virtual-size ( RO): 21474836480
            sharable ( RO): false
           read-only ( RO): false

The objective is to set a proper name and description to VDI disk.

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Secure SSD data deletion

Normal data deletion does not erase all data from SSD as same parts are reserved and omitted by removal process. The function secure erase function allows for a complete data removal from all cells. The secure erase function is offered by SSD manufactures and not all hard drives or Linux kernels support it. In the below examples we will refer to /dev/sda block device as our test drive. To find whether your SSD hard drive supports secure erase run a following linux command:

Warning:

ATA Security Feature Set
These switches are DANGEROUS to experiment with, and might not work with some kernels. USE AT YOUR OWN RISK.

# hdparm -I /dev/sda | grep erase
		supported: enhanced erase

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