Systemd – run a script before system shutdown

Here systemd will execute /srv/app_shutdown_script.sh before the system reboots. Refer to the following steps. Create a systemd Unit file with the following content. # cat /etc/systemd/system/exec-before-shutdown.service [Unit] Description=Shutdown run script…

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logrorate: error: lines must begin with a keyword or a filename (possibly in double quotes)

Logrotate command returns the following error: # logrotate -vf /etc/logrotate.d/mylog reading config file mylog reading config info for /var/log/mylog.log error: iptables:1 lines must begin with a keyword or a filename…

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OpenSSL

How to convert a .cer to .pem format

The following OpenSSL command will convert a .cer file to .pem format. $ openssl x509 -inform der -in certificate.cer -outform pem -out certificate.pem

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Squid Kerberos Authentication

Squid configuration to allow internet access to specific AD group

Squid is a caching web proxy server helps in speeding up a web server by caching repeated requests, caching web, DNS and other computer network lookups for a group of…

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Squid Kerberos Authentication

Squid Kerberos authentication configuration on Linux/Debian/Ubuntu/CentOS

Squid is a caching web proxy, provides a wide variety of uses, including speeding up a web server by caching repeated requests, caching web, DNS and other computer network lookups…

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Linux Wifi Router

Configure a Linux system as a wifi router or hotspot

This article provide a simple and precise steps to create a Wi-Fi Hotspot or router on Ubuntu / Debian / Fedora / CentOS / RHEL/ Arch Linux system using nmcli…

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sudo log configuration on Linux

Enabling sudo log helps system administrators to track the activities of sudo users and this helps in system auditing. sudo logging logs all sudo commands executed on Linux system. This... Read more »
Linux sudo-io

sudo-io configuration on Linux

sudo-io is needed to log all sudo commands executed on Linux system with the command input and output stream. This article provides a step by step instruction to configure sudo-io... Read more »
DRBD Replication

DRBD Cheat Sheet

DRBD is a distributed replicated storage system for the Linux platform. It is implemented as a kernel driver, several userspace management applications, and some shell scripts. This article describes about... Read more »
Remove a faulty node and add a new node on Pacemaker cluster

Remove a faulty node and add a new node on Pacemaker cluster

Sometimes cluster nodes may fail from cluster due to disk failure, operating system crash or some other reason. Here in this demonstration we will configure, how to remove a failed... Read more »