Sync an accurate time using ntpdate on RHEL7 Linux server

To sync a correct time on your Redhat server with a NTP publicly available time servers first you need to install ntpdate package:

[root@rhel7 ~]# yum install ntpdate

To check your current time use date command:

[root@rhel7 ~]# date
Thu Sep  4 17:20:42 WST 2014

Next, we can use timeserver to synchronize our time. This is be done with ntpdate command:

[root@rhel7 ~]# ntpdate
11 Dec 06:08:13 ntpdate[2225]: step time server offset 8426822.014383 sec

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Update GRUB2 menu timeout on RHEL 7 Linux

The default settings for the GRUB2 timeout menu selection during the system boot is 5 seconds. To change this value open /etc/default/grub grub default config file. The content of the file looks similar the the one shown below:

GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_CMDLINE_LINUX=" crashkernel=auto  \ vconsole.font=latarcyrheb-sun16 vconsole.keymap=us rhgb quiet"

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Persistent/Automatic after reboot kernel module loading on CentOS/Redhat Linux

This config will describe a procedure on how to persistently load kernel modules during a boot time on CentOS or Redhat Linux system. In the below commands will use nf_conntrack_pptp as a sample module. Replace the name of this module with a module name you wish to load.

First, create a script within /etc/sysconfig/modules/ directory with a file extension modules. Where the name of the script can be any name of your choice. In our case the script will be called nf_conntrack_pptp.modules. Enter a following code into your new nf_conntrack_pptp.modules script while replacing the name of the module with the one you wish to load:

exec /sbin/modprobe nf_conntrack_pptp  >/dev/null 2>&1

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How to reset the root password in RHEL7/CentOS7/Scientific Linux 7- based systems


Resetting the root password in RHEL7/CentOS7/Scientific Linux 7


RHEL7 / CentOS7 / Scientific Linux 7




Things have changed in the RHEL7 world and so has the preferred way of resetting the root password. Although the old way of interrupting the boot process (init=/bin/bash) still works, it is no longer bulletproof and recommended.
‘Systemd’ uses ‘rd.break’ to interrupt the boot. Let’s have a quick walk through the whole procedure.

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VNC connection to RHEL

Configuring VNC Server Access on a Redhat Linux

Most of the time as a Linux system administrator you are managing your servers over the network. It is very rare that you will need to have a physical access to any of your managed servers. In most cases all you need is to SSH remotely to do your administration tasks. In this article we will configure a GUI alternative to a remote access to your RHEL server, which is VNC. VNC allows you to open a remote GUI session to your server and thus providing you with a full graphical interface accessible from any remote location.

In this tutorial you will learn:

  • How to install required VNC packages
  • How to setup and start the VNC server on RHEL
  • How to connect to a graphical session remotely
  • How to run graphical programs in the xterm session

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