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Author: Albert

Disable and enable ceilometer in OpenStack

Stop telemetry on the overcloud controllers. systemctl stop openstack-aodh-evaluator openstack-aodh-listener openstack-aodh-notifier openstack-ceilometer-central openstack-ceilometer-collector openstack-ceilometer-notification openstack-gnocchi-metricd openstack-gnocchi-statsd Next stop the mongod service. systemctl stop mongod You should now backup MongoDB files. tar Jcf /tmp/mongodb-backup-$HOSTNAME-$(date +%F_%H%M%S).tar.xz /var/lib/mongodb Delete the content of /var/lib/mongodb folder as follows: rm -r /var/lib/mongodb/* Run mongodb on all controllers. systemctl start mongod Create …

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can’t find command `multiboot2′ – TBOOT fails in UEFI system

In a UEFI system, after installing TBOOT, the TBOOT GRUB menu entries fail to boot the kernel. The following error message will be output on the screen. error: ../../grub-core/fs/fshelp.c:218:file`/EFI/centos/x86_64-efi/multiboot2.mod' not found.Loading tboot 1.10.2 ... error: ../../grub-core/script/function.c:120:can't find command `multiboot2'.Loading Linux 4.18.0-305.10.2.el8_4.x86_64 ...error: ../../grub-core/script/function.c:120:can't find command `module2'.Loading initial ramdisk ...error: ../../grub-core/script/function.c:120:can't find command `module2'. Press any …

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Bitcoin

Cryptocurrency Mining Explained

What is Cryptocurrency mining Cryptocurrency mining or crypto mining uses computational power to generate new cryptocurrency units by solving complex mathematical problems or algorithms. The cyber currency transactions are verified, and the miners (like auditors) distributed globally are rewarded with a small percentage of cyber currency. e.g., Bitcoin, Etherium, BTC, Dogecoin, etc. Cryptomining can be …

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How to change the color of the default black Font Awesome icons

You can add the color to the HTML element as follows: <i class="fa fa-car" style="color:#DDDDDD;"><!-- icon --></i> You can also change the size of the icon as follows: <i class="fa fa-car fa-lg" style="color:#DDDDDD;"><!-- icon --></i> <i class="fa fa-car fa-4x" style="color:#DDDDDD;"><!-- icon --></i> You can also make site-wide changes with CSS as follows: .fa {color: black;}.fa-car …

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How to disable bash shell history

You can use two methods to disable saving shell history in bash. Method 1: Add the following line at the end of /etc/profile or make a new file in /etc/profile.d/ with .sh extension. unset HISTFILE With the above option, the user’s bash shell will not save history unless manually configures the HISTFILE variable. Method 2: …

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How to configure system wide proxy for all users shells and yum

http_Proxy environment variable is used to specify proxy settings to wget and curl. To find the proxy server already set on a Linux machine, use the following command: echo $http_proxy To set http_proxy without username and password: export http_proxy=http://SERVER-NAME:PORT/ To set http_proxy with username and password: export http_proxy=http://USER-NAME:PASSWORD@SERVER-NAME:PORT/ To set http_proxy with username, password, and …

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How to log all bash history commands to syslog

shopt is a built-in bash variable that enables bash history to be written to /var/log/messages. shopt -s syslog_history If you want to unset it, run the following command. shopt -u syslog_history In order for these audit activities to persist in all bash sessions, append the following to the bottom of /etc/bashrc file. shopt -s syslog_history

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Bash Shell Scripting Cheat Sheet for AlmaLinux, CentOS, and Ubuntu

Bash is by default installed on most Linux distributions like AlmaLinux, CentOS, Kali, and Ubuntu. The following cheat sheet outlines some important features of bash scripting. Bash Script Header #!/usr/bin/env bashecho “Hello World” Variables #!/usr/bin/env bashMSG=”Hello World”echo “$MSG Albert” # Hello World Albertecho ‘$MSG Albert # $MSG Albert Strings MSG=”hello world” Replace echo ${MSG/w/W} # …

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How to install Nvidia drivers on Kali linux

First, update Kali Linux based server as follows: sudo apt updatesudo apt -y full-upgrade Reboot server as follows: reboot Find out which video card is installed in the Kali Linux server and verify using the nouveau open-source driver. lspci | grep -i vga You will get the following output: 00:02.0 VGA compatible controller: NVIDIA Corporation …

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