Lubos Rendek

How to install Google Chrome Browser on Ubuntu 16.04 Xenial Xerus Linux

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Objective

The objective is to install Google Chrome browser on on Ubuntu 16.04 Xenial Xerus Linux.

Requirements

Privileged access to your Ubuntu 16.04 Xenial Xerus Linux Desktop

Difficulty

EASY

Conventions

  • # – requires given linux commands to be executed with root privileges either directly as a root user or by use of sudo command
  • $ – requires given linux commands to be executed as a regular non-privileged user

Instructions

Install gdebi

The easiest way to install external *.deb packages such as google chrome, is by use of gdebi tool. gdebi will automatically fetch and install all chrome’s dependencies. If you have not done so yet, install gdebi now:

$ sudo apt-get install gdebi

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Howto install ifconfig on CentOS 7 Linux

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Objective

The the network command line tool ifconfig is not installed thus missing by default on CentOS 7 Linux. Users are instead encouraged to use ip command to do most of the network administration work.

For example the following ip command can be used to show IP address on CentOS 7:

# ip address show
OR SIMPLY
# ip a s
1: lo:  mtu 65536 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0:  mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether f2:d9:fc:79:72:d7 brd ff:ff:ff:ff:ff:ff
    inet 10.1.1.145/8 brd 10.255.255.255 scope global dynamic eth0
       valid_lft 861944sec preferred_lft 861944sec
    inet6 fe80::f0d9:fcff:fe79:72d7/64 scope link 
       valid_lft forever preferred_lft forever
3: virbr0:  mtu 1500 qdisc noqueue state DOWN 
    link/ether 52:54:00:e3:e3:3e brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
4: virbr0-nic:  mtu 1500 qdisc pfifo_fast master virbr0 state DOWN qlen 500
    link/ether 52:54:00:e3:e3:3e brd ff:ff:ff:ff:ff:ff

However, it is still possible to use the old-fashioned ifconfig command. Thus our objective is to install ifconfig on CentOS 7 Linux which is a part of net-tools package.

Requirements

Privileged access to your CentOS 7 Linux server/desktop.

Difficulty

EASY

Conventions

  • # – requires given linux commands to be executed with root privileges either directly as a root user or by use of sudo command
  • $ – requires given linux commands to be executed as a regular non-privileged user

Instructions

CentOS 7 ifconfig install

Execute the following yum command in order to install ifconfig on CentOS 7:

# yum install net-tools

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Docker installation on RHEL 7 Linux

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Objective

The objective is to install Docker engine on Redhat 7 Linux using native docker script.

Requirements

Internet connection as well as a privileged access to your Redhat 7 Linux is required.

Difficulty

EASY

Conventions

  • # – requires given linux commands to be executed with root privileges either directly as a root user or by use of sudo command
  • $ – requires given linux commands to be executed as a regular non-privileged user

Instructions

Install docker

Installation of docker using a native docker script is one command, straight forward process. Before you run the below docker installation command ensure that curl package is installed on your system:

# curl --version
curl 7.29.0 (x86_64-redhat-linux-gnu)

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Unbound cache-only DNS server setup on RHEL 7 Linux

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Introduction

Unbound is a validating, recursive, and caching DNS server. Having said that, Unbound DNS server cannot be used as an authoritative DNS server, which means it cannot be used to host custom domain name records. As a result, if your goal is to build a cache-only or forwarding DNS server, Unbound may be your preferred choice, as it does just that and it does it well.

Objective

The objective is to provide quick and easy to follow installation and configuration guide for the Unbound cache-only DNS server on Redhat 7 Linux. At the end of this guide you will be able to use Unbound DNS server from all clients on your local area network.

Requirements

Privileged access to your Redhat 7 Linux server with configured standard RedHat repositories.

Difficulty

MEDIUM

Conventions

  • # – requires given linux commands to be executed with root privileges either directly as a root user or by use of sudo command
  • $ – requires given linux commands to be executed as a regular non-privileged user

Instructions

Unbound and DNS tools installation

In the first step we are going to install the actual Unbound DNS server as well as DNS tools which will be eventually used to test your DNS cache-only server configuration. Given that you have your Redhat repository configured correctly you can install both by executing the following linux command:

# yum install unbound bind-utils

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

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

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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 instruct XenServer’s host virtual machine to boot from ISO CD/DVD image

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Objective

Here we assume that you have already created VM’s device to link to desired ISO image you wish to boot from. The objective is to instruct XenServer’s host virtual machine to boot from ISO CD/DVD image instead of default VDI disk. Failure to do so may result in following error message:

The bootloader returned an error
msg: Unable to find partition containing kernel

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How to refresh XenServer’s storage repository to include newly added items

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Objective

Suppose that we have included a new item to our Xenserver’s storage repository such as the newly downloaded ISO images. XenServer would not list this item immediately and thus this requires a manual action to include this new item into XenServer’s storage repository list. The objective is to rescan XenServer’s storage repository thus make all new items available for use.

Requirements

Administrative Local or Remote command line access to XenServer is required to complete this task.

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How to create a new virtual machine on XenServer using command line

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Objective

Deployment of XenServer virtual machine using command line.

Requirements

Privileged access to XenServer’s command line as well as configured ISO image storage containing an ISO image of the Linux distribution you wish to install.

Difficulty

MODERATE

Instructions

Deploy VM template and gather information

In this guide we will be creating a new Ubuntu Linux based virtual machine. However, the below procedure will fit any decent Linux distribution as along as it is supported by XenServer, meaning that the template for the Linux distribution you would like to install is part of the XenServer’s repertoire. Let’s first search XenServer’s database for a template name.

In this case we are looking for Ubuntu 16.04:

# xe template-list | grep name-label | grep -i 16.04
          name-label ( RW): Ubuntu Xenial Xerus 16.04

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