Configure CentOS to Sync with NTP Time Servers

 CentOS 7 / RHEL 7, Clusterweb, ClusterWeb, Leitura Recomendada, Linux, Profissional de TI  Comentários desativados em Configure CentOS to Sync with NTP Time Servers
ago 012019
 

Over the years, We’ve encountered many questions on how to correctly configure our Linux hosts to sync time to our enterprise NTP Servers.

So, We thought why not create an article that outlines in the simplest form possible the correct way to configure the NTP Client to synchronize with NTP Servers.

Sync CentOS with NTP Time Servers

First of all, we need to install the ntpd and ntpdate clients on our Linux host. I’m using CentOS, but it’s the same in Ubuntu and so forth.

# yum install ntp ntpdate
# systemctl start ntpd
# systemctl enable ntpd
# systemctl status ntpd

Now let’s run the following command to configure the NTP Servers.

# ntpdate -u -s 0.centos.pool.ntp.org 1.centos.pool.ntp.org 2.centos.pool.ntp.org

What we’re doing is telling the ntpdate to use an unprivileged port for outgoing packets with the -u switch and to write logging output to the system syslog facility using the -s switch.

Next let’s restart the ntpd daemon.

# systemctl restart ntpd

Now let’s check if NTP synchronization is enabled and running.

# timedatectl

And for the last, we will set the hardware clock to the current system time using the -w switch.

# hwclock -w

Congratulations! You’ve now successfully set your NTP client on CentOS.

Migration of servers to Proxmox VE

 Clusterweb, Profissional de TI, Proxmox, Segurança, Virtualização  Comentários desativados em Migration of servers to Proxmox VE
jun 222018
 

Introduction

You can migrate existing servers to Proxmox VE. Moving Linux servers is always quite easy so you will not find much hints for troubleshooting here.

Windows systems specific P2V issues

inaccessible boot device

Booting a virtual clone (IDE) of a physical Windows system partition may fail with a BSOD referring to the problem

STOP: 0x0000007B (0xF741B84C,0xC0000034,0x00000000,0x00000000)
INACCESSIBLE_BOOT_DEVICE 

this means that the source physical windows machine had no support for IDE controller, or at least the one virtually replaced by kvm (see Microsoft KB article article for details): as Microsoft suggests, create a mergeide.reg file (File:Mergeide.zip) file on the physical machine and merge that in the registry, ‘before the P2V migration. Btw, it may not be necessary but should be no harm, anyway, and save you lots of time and headaches.

Continue reading »