Cloning KVM virtual machine using CLI

To clone your VM and spawn new instances in KVML

# virt-clone --original {Domain-Vm-Name-Here} --auto-clone

OR

# virt-clone --original {Domain-Vm-Name-Here} --name {New-Domain-Vm-Name-Here} --auto-clone

OR

# virt-clone --original {Domain-Vm-Name-Here} \
--name {New-Domain-Vm-Name-Here} --file {/var/lib/libvirt/images/File.Name.here}

Continue reading “Cloning KVM virtual machine using CLI” »

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Install Lancache on Debian 10

Step 1: Installing Docker

The Docker installation package available in the official Debian repository may not be the latest version. To ensure we get the latest version, we’ll install Docker from the official Docker repository. To do that, we’ll add a new package source, add the GPG key from Docker to ensure the downloads are valid, and then install the package.

First, update your existing list of packages:

sudo apt update

Next, install a few prerequisite packages which let apt use packages over HTTPS:

sudo apt install apt-transport-https ca-certificates curl gnupg2 software-properties-common

Then add the GPG key for the official Docker repository to your system: Continue reading “Install Lancache on Debian 10” »

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Upgrade Debian 9 to Debian 10

Update ALL existing installed packages

Before you upgrade your Debian version to 10, you must apply all security patches and pending upgrades to Debian 9 itself Hence, Type the following apt command or apt-get command:

sudo apt update
sudo apt upgrade
sudo apt full-upgrade
sudo apt --purge autoremove

OR

sudo apt-get update
sudo apt-get upgrade
sudo apt-get full-upgrade
sudo apt-get --purge autoremove

Reboot the Debian 9.x stretch to apply the kernel and other updates: Continue reading “Upgrade Debian 9 to Debian 10” »

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Large file split and join in linux

Let’s assume we have a large file of 102 GB and named as “vzdump-lxc-103-2021_07_19-12_05_06.tar.lzo”. We’d like to split this large file into 10GB of partial file. Let’s apply the split command as below-

split -b 102400M vzdump-lxc-103-2021_07_19-12_05_06.tar.lzo repo.

Wait for a while, the execution continues, and once over, you’ll find 11 split files altogether- Continue reading “Large file split and join in linux” »

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Using multiple gateways on Windows system

If Windows has multiple interfaces connected to several networks that use DHCP, it installs default gateways for all those interfaces.

By default, Windows sets the metric of the default gateways to the same, effectively leading to random selection of default gateway.

If you want to make Windows to select certain gateway always, you can change interface metrics for the interfaces’ configuration you don’t want to use:

  1. Go to your Network adapter properties.
  2. Select Internet Protocol v4.
  3. Click the Advanced button on General tab.
  4. Uncheck Automatic metric.
  5. Enter a number higher than 10 to the Interface metric field.
  6. The default automatic metric for interfaces is 10. The lower the metric, the higher the preference to use it.
  7. So, you have to enter metric higher than 10 for the interfaces you don’t want to use.

EDIT: These instructions are for Windows 7, XP might be different. You shouldn’t be using XP anyway.

Src: https://superuser.com/questions/735479/how-does-a-windows-computer-behave-when-it-has-multiple-default-gateways/735569

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CentOS 7 XFS disk resizing

Couldn’t find any article that explained step by step how to resize the main disks volume in a CentOS 7 vm. In my example I started witha single disk of 8GB and expanded to 20GB. I have two partitions on disk sda

sda1 type Linux for boot
sda2 type Linux LVM for the remaining logical volumes

Space utilisation as following:

[root@vcd-c1-s1 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 3.9G 0 3.9G 0% /dev
tmpfs 3.9G 0 3.9G 0% /dev/shm
tmpfs 3.9G 8.8M 3.9G 1% /run
tmpfs 3.9G 0 3.9G 0% /sys/fs/cgroup
/dev/mapper/centos-root 6.2G 1.9G 4.4G 31% /
/dev/sda1 1014M 179M 836M 18% /boot
tmpfs 783M 0 783M 0% /run/user/0

We basically need to: Continue reading “CentOS 7 XFS disk resizing” »

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Install Virtualbox 5.2/6.1 on Ubuntu 16 headless mode

Install Prerequisites

Before installing VirtualBox 5.2/6.1, please install these packages below if your systems don’t already have them installed….

sudo apt update
sudo apt-get install gcc make linux-headers-$(uname -r) dkms

Add VirtualBox Repository

If you want to always get the latest versions of VirtualBox when they become available, you’ll want to add its software repository to Ubuntu…

Run the commands below to add the repository key to your system…

wget -q https://www.virtualbox.org/download/oracle_vbox_2016.asc -O- | sudo apt-key add -
wget -q https://www.virtualbox.org/download/oracle_vbox.asc -O- | sudo apt-key add -

After adding the repository key above, run the commands below to add VirtualBox package repository.

sudo add-apt-repository "deb [arch=amd64] http://download.virtualbox.org/virtualbox/debian $(lsb_release -cs) contrib"

After that, run the commands below to update Ubuntu repositories.

Installing VirtualBox

At this point, the Ubuntu system should be ready to install the latest version of VirtualBox. First you may want to remove the previous 6.0 version if you’re still running it… to do that, run the commands below:

sudo apt remove virtualbox virtualbox-6.1

Finally, run the commands below to install the latest 6.1 (major) version of the software. Continue reading “Install Virtualbox 5.2/6.1 on Ubuntu 16 headless mode” »

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Reset user password of Discourse

Discourse is an excellent platform- super fast, super organized and super fresh looking. It has quite standarized and additional security options in the application UI. However, found a freat issue of updating any user of this platform as Admin (I was havign difficulties of self user password reset options, as the mail gateway was somewhat not working). 

So here goes the trick-

ssh into your server

cd /var/discourse
./launcher enter app
 rails c 
u = User.find_by_email('email@test.com') 
u.password='zKRR6vTZKvJAB84V9jdgeydS' 
u.save!
ctrl+d to exit
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