If you currently do not hold a Red Hat Subscription and yet you need to enable EPEL ( Extra Packages for Enterprise Linux ) repository on your RHEL 7 Linux you need to download and install following file directly from Fedora project:
epel-release-7-5.noarch.rpm
There are number of ways how to find you what Redhat Linux version is my server running on. First check /etc/os-release file:
# cat /etc/os-release NAME="Red Hat Enterprise Linux Server" VERSION="7.0 (Maipo)" ID="rhel" ID_LIKE="fedora" VERSION_ID="7.0" PRETTY_NAME="Red Hat Enterprise Linux Server 7.0 (Maipo)"
In this config we are going to configure a network interface to receive an IP configuration settings from DHCP server. First get the name of the network interface you would like to set as DHCP client. To do this you can run command:
# ip addr show
2: enp0s3: mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 08:00:27:15:38:b7 brd ff:ff:ff:ff:ff:ff
valid_lft forever preferred_lft forever
inet6 fe80::a00:27ff:fe15:38b7/64 scope link
valid_lft forever preferred_lft forever
Once we have located a name of the network interface in question open a corresponding configuration file. So as an example, for network interface epn0s3 vi will edit a /etc/sysconfig/network-scripts/ifcfg-enp0s3. Open this file and enter the minimum configuration settings in order to make this network interface act as a DHCP client:
DEVICE=enp0s3 BOOTPROTO=dhcp ONBOOT=yes
Instead of changing a hostname on your Redhat 7 server manually by editing /etc/hostname you may preferably use a dedicated command hostnamectl to do this job. By default when no other options are supplied the hostnamectl command will display basic information including static hostname:
[root@rhel7 ~]# hostnamectl
Static hostname: rhel7
Icon name: computer
Chassis: n/a
Machine ID: 75387b56d72b44b380810499805ec28a
Boot ID: 6ad251d0e12a10e3af1894eae5fe5cb6
Virtualization: oracle
Operating System: Red Hat Enterprise Linux Server 7.0 (Maipo)
CPE OS Name: cpe:/o:redhat:enterprise_linux:7.0:GA:server
Kernel: Linux 3.10.0-123.el7.x86_64
Architecture: x86_64
The following linux command will list all available locales currently available on the Redhat 7 system:
[root@rhel7 ~]# localectl list-locales
The list of all available locales on your system my be quite long so use grep command to narrow down your search. Bellow command will display for example all German available locales:
[root@rhel7 ~]# localectl list-locales | grep ^de de_AT de_AT.iso88591 de_AT.iso885915@euro de_AT.utf8 de_AT@euro de_BE de_BE.iso88591 de_BE.iso885915@euro de_BE.utf8 de_BE@euro de_CH de_CH.iso88591 de_CH.utf8 de_DE de_DE.iso88591 de_DE.iso885915@euro de_DE.utf8 de_DE@euro de_LU de_LU.iso88591 de_LU.iso885915@euro de_LU.utf8 de_LU@euro deutsch
Use localectl to see your currently active locale on Redhat 7 Linux. For example:
[root@rhel7 ~]# localectl
System Locale: LANG=en_AU.UTF-8
VC Keymap: us
X11 Layout: us
Changing a timezone on Redhat 7 Linux server is a easy task which can be done on a command line with a few commands. First find your timezone using timedatectl command. The following linux command will list all timezones:
[root@rhel7 ~]# timedatectl list-timezones
To narrow down the search you can use grep to search for a specific city. For example:
[root@rhel7 ~]# timedatectl list-timezones | grep -i bratislava Europe/Bratislava
When not using NTP you may need to set your system time manually. You have two options to set time and date on your RHEL7 linux. First option is to use date command to do this job or engage dedicated systemd timedatectl command. By default and without any arguments timedatectl will display a current time, local, universal and RTC times:
[root@rhel7 ~]# localectl
System Locale: LANG=en_AU.iso88591
VC Keymap: us
X11 Layout: us
[root@rhel7 ~]# timedatectl
Local time: Thu 2014-09-04 18:30:11 WST
Universal time: Thu 2014-09-04 10:30:11 UTC
RTC time: Thu 2014-09-04 10:30:10
Timezone: Australia/Perth (WST, +0800)
NTP enabled: n/a
NTP synchronized: no
RTC in local TZ: no
DST active: n/a
I would like to know how to check gnome desktop manager version on my Redhat 7 Linux server/desktop?
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 pool.ntp.org timeserver to synchronize our time. This is be done with ntpdate command:
[root@rhel7 ~]# ntpdate pool.ntp.org 11 Dec 06:08:13 ntpdate[2225]: step time server 173.230.144.109 offset 8426822.014383 sec
Once you configure NTPD service on your RHEL7 linux you will need to allow traffic through the firewall on port 123. Te following linux command will enable all public traffic on UDP port 123:
# firewall-cmd --zone=public --add-port=123/udp --permanent success
Resetting the root password in RHEL7/CentOS7/Scientific Linux 7
RHEL7 / CentOS7 / Scientific Linux 7
MODERATE
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.