memtest+ redhat 7 grub menu available

Installation of Memtest+ RAM memory test tool on Redhat 7 Linux

Installation of Memtest+ RAM memory test tool on Redhat 7 Linux

Memtest is a quite handy tool when troubleshooting hardware problem and specifically problems related to Random Access Memory (RAM). After installation the memtest+ tool will become available among other boot options. To install memtest+ on RHEL 7 Linux server execute the following linux command:

# yum install memtest86+
...
Running transaction
  Installing : memtest86+-4.20-12.el7.x86_64      1/1 
  Verifying  : memtest86+-4.20-12.el7.x86_64      1/1 

Installed:
  memtest86+.x86_64 0:4.20-12.el7

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Open http port 80 firewall rule on RHEL7 linux httpd

How to open http port 80 on Redhat 7 Linux using firewall-cmd

By default the port 80 for http connection is filtered on Redhat 7 as you can only access this port from the actual localhost and not from any other public host. To open a port 80 on RHEL 7 Linux we need to add an iptables rule. For this RHEL7 uses firewall-cmd. First add your port 80 rule with a following linux command:

[root@rhel7 ~]# firewall-cmd --zone=public --add-port=80/tcp --permanent

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Monitor CPU temperature on Redhat 7 Linux

How to monitor a CPU temperature on Redhat 7 Linux system

Here is a short config to show you how to display and monitor CPU temperature on a Linux system running Redhat 7 Linux. First we need to install lm_sensors:

# yum install lm_sensors

Next, use sensors command to display CPU temperature:

$ sensors | grep Core
Core 0:         +43.0°C  (high = +86.0°C, crit = +100.0°C)
Core 1:         +43.0°C  (high = +86.0°C, crit = +100.0°C)

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How to install, manage, start and autostart ssh service on RHEL 7 Linux

systemctl command is used on RedHat 7 linux to manage services system wide. It allows administrators to manage ssh service to start, restart, stop or enable autoload after system startup.

In install ssh service on your RHEL 7 linux run a following linux command:

# yum install openssh

By defalt SSH service or to be more precise sshd ( daemon ) is disabled. Once the opensshd package installed, you can check the status of SSHD service by using the below command:

# systemctl status sshd
sshd.service - OpenSSH server daemon
   Loaded: loaded (/usr/lib/systemd/system/sshd.service; disabled)
   Active: inactive (dead)

To start ssh daemon (sshd) on RHEL 7 run:

systemctl start sshd

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

Objective

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

Requirements

RHEL7 / CentOS7 / Scientific Linux 7

Difficulty

MODERATE

Instructions

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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