Category: Linux
Heap Memory
Heap Memory, it starts from lower address and increases to higher address malloc malloc(size) allocate memory, return a pointer realloc(pointer, size) resize currently allocated memory for bigger or lower by relocating, return a pointer free() remove allocated memory calloc() like malloc but create a memory with zeros, better for security to prevent memory leaks! dlmalloc()
Run MySQL Cluster Multi Masters For High Availability
Hello Folks, it’s has been a while I didn’t write new articles, it’s has been a while I didn’t write new articles, so time to give back to the community, I will describe how to implement MySQL cluster for high-availability and disturbed workload MySQL Cluster Architect comes with new process ndbd and ndb_mgmd ndb is used
Linux Performance Co-Pilot with WebUI
Performance Co-Pilot allow sysadmins to collect and measure data from various systems, it comes in RPM packages for Red Hat 6 to 7 website http://pcp.io/ installing Performance CO-Pilot
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yum -y install pcp |
pcp packages comes with different services pmcd,pmlogger pmcd : performance metrics collector daemon
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[root@localhost ~]# systemctl enable pmcd ; systemctl start pmcd ; systemctl status pmcd pmcd.service - Performance Metrics Collector Daemon Loaded: loaded (/usr/lib/systemd/system/pmcd.service; enabled) Active: active (exited) since Sat 2016-07-23 07:17:24 EDT; 1min 1s ago Docs: man:pmcd(8) Main PID: 4717 (code=exited, status=0/SUCCESS) CGroup: /system.slice/pmcd.service ├─4862 /usr/libexec/pcp/bin/pmcd ├─4865 /var/lib/pcp/pmdas/root/pmdaroot ├─4866 /var/lib/pcp/pmdas/proc/pmdaproc -d 3 ├─4867 /var/lib/pcp/pmdas/xfs/pmdaxfs -d 11 └─4868 /var/lib/pcp/pmdas/linux/pmdalinux Jul 23 07:17:24 localhost.localdomain systemd[1]: Starting Performance Metrics Collector Daemon... Jul 23 07:17:24 localhost.localdomain pmcd[4717]: Rebuilding PMNS ... Jul 23 07:17:24 localhost.localdomain pmcd[4717]: Starting pmcd ... Jul 23 07:17:24 localhost.localdomain systemd[1]: Started Performance Metrics Collector Daemon. Jul 23 07:18:26 localhost.localdomain systemd[1]: Started Performance Metrics Collector Daemon. [root@localhost ~]# |
pcp packages come with many commands to gather information about the machine like
IPtables PREROUTING, POSTROUTING for mixed interfaces via DNAT & SNAT
hello world, let’s hit the point directly 1 – we have traffic coming from Source IP to our box and we need to Route it to another destination ( traffic forwarding ) 2- we have traffic coming from Source IP to our box and we need to Route it to another destination ( traffic forwarding )
phpMyAdmin error #1146
#1146 – Table ‘phpmyadmin.pma_tracking’ doesn’t exist this error indicates that phpmyadmin pages failed in setup and you just ignored it in the setup process you need to reconfigure the package again
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root@ubuntu:~# dpkg-reconfigure phpmyadmin |
after you follow the reinstall steps it will setup the missing sql files for pma tables
phpMyAdmin no password dev env
if you setup your development environment with no mysql root password after you setup phpmyadmin package it will land you with this error Login without a password is forbidden by configuration (see AllowNoPassword) to fix this error vi /etc/phpmyadmin/config.inc.php find line : 96 ” /* $cfg[‘Servers’][$i][‘AllowNoPassword’] = TRUE;” remove the comment /* $cfg[‘Servers’][$i][‘AllowNoPassword’] = TRUE;
Fix Mcrypt WARNING Ubuntu Server
today I faced problem in setup a mcrypt module I did install it via
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apt-get install mcrypt php5-mcrypt |
when i did try to enable it via
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php5enmod mcrypt |
I got this error root@ubuntu:/etc/php5/apache2/conf.d# php5enmod mcrypt WARNING: Not enabling the mcrypt module for apache2 SAPI since module symlink WARNING: already exists in /etc/php5/apache2/conf.d with different content. WARNING: Not enabling the
Docker Containers Crash Course
Docker Crash Course As Hypervisor is slow to boot and use a lot of resources and needs full installation the Container Technology not that old we used to use LXC – openVZ extra but what a cool about Docker is it really lightweight with awesome images build and we can ship many services in one
audit keystrokes with pam
The pam_tty_audit PAM module is used to enable or disable TTY auditing. By default, the kernel does not audit input on any TTY this module is part of auditd and it takes 3 parameters 1 – disable is a pattern to disable the module in specified users u can use =* to disable it globally
Protect Boot & Single user mode
as a physical security is the main factor in our security perspective we all need to protect unauthorised access to our Linux box after we protect bios and we all know that anyone can rest the root password via accessing the single mode so we have 3 ways 1st thing to disable single user mode entirely