December 2017 – Cornucopia of Ideas…

SSL Client Certificate Authentication with Apache

24/12/2017

Creating CA Certificate We use this certificate for only signing certificates that we use for the clients and our web servers. It should be kept very secure. If it is disclosed other certificates signed with this certificate will be disclosed as well.

openssl genrsa -des3 -out ca.key 4096
openssl req -new -x509 -days 365 -key ca.key -out ca.crt

1 2	openssl genrsa -des3 -out ca.key 4096 openssl req -new -x509 -days 365 -key ca.key -out ca.crt

Creating a Key and CSR for the Client Creating a client certificate […]

Fake Kernel Panic for Testing(Magic SysRq)

18/12/2017

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Sometimes we need to crash the system for testing of cluster fencing functionality and fail-over functionality. Actually in Linux we can create a fake kernel panic by issuing below commands.

root@ankara # echo 1 > /proc/sys/kernel/sysrq  #1 - enable all functions of sysrq
root@ankara # echo "c" > /proc/sysrq-trigger   #

1 2	root@ankara # echo 1 > /proc/sys/kernel/sysrq #1 - enable all functions of sysrq root@ankara # echo "c" > /proc/sysrq-trigger #

c Will perform a system crash by a NULL pointer dereference. A crash dump will be taken if configured. Reference: https://www.kernel.org/doc/html/v4.11/admin-guide/sysrq.html

System Restore with Rsync

12/12/2017

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Rsync is one of the super-duper *nix utility for synchronizing or transferring files among the computers. It has so much functionality that I could not explain it to you in one post. In this post, I will use rsync utility to backup and restore my system. In this activity, I am using CentOS7(virtual guest) on […]