Question: How to change bonding Network configuration to simple network configuration? The high level steps are: stop the bonding interface. change the network configuration from the bonding to simple network interface. then start the simple network interface. For example, if the bonding interface is: bond0, and it is bonded with eth0 and eth1. And you […]
CentOS/RHEL 6
Configure dnsmasq to use different DNS Servers for some Domains (CentOS/RHEL)
By default, the operating system uses the dns servers configured in /etc/resolv.conf and for each lookup it will ask the same set of dns servers. It is possible to configure dnsmasq to use different dns servers for specific domains. When looking for entries in xyz.com dnsmasq should ask dns server 192.168.1.1, and when using abc.com, […]
How to Stop “sudo” from Sending Emails on Failures in CentOS/RHEL
The Problem When a sudo command fails a mail is triggered when the messages below appears: Apr X 04:30:28 XXX2 sudo[12591]: pam_vas: Authentication for user: account: service: reason: Apr X 04:30:28 XXX2 sudo: rtp : pam_authenticate: Conversation error ; TTY=unknown ; PWD=/home/rtp ; USER=root ; COMMAND=/sbin/ethtool public:2 Apr X 04:30:28 XXX2 sudo: rtp : command […]
How to Install SSHFS on CentOS/RHEL/Ubuntu
Whats is SSHFS There are several ways to share a directory across a network. In enterprise settings, you’ll find the Network Filesystem (NFS), Samba, and various distributed filesystems. SSHFS isn’t used in enterprises quite as much, but it can still come in handy. The beauty of it is that all of its network traffic is […]
Integrate Linux Servers with Active Directory using Samba, Winbind, and Kerberos
In this tutorial, we will discuss how to integrate Linux Servers(Centos/RHEL) with Windows Active Directory for authentication purposes. In my case, I have Centos/RHEL 6 servers. Follow the below steps to integrate these servers with AD using samba, winbind, and Kerberos. Step 1: Install the samba-winbind and kerberos packages. # yum install samba-winbind samba-winbind-clients samba […]
Zenoss Core Installation & Configuration on CentOS/RHEL 6.X
Zenoss is an open-source real-time monitoring tool and comes under GNU General Public License (GPL) version 2. It provides a web interface that allows system administrators to monitor availability, inventory/configuration, performance, and other events. Most Common Features: Application, Network and Systems Monitoring and Management Alerting and Automatic Remediation System Log Monitoring and Event Management Automated […]
Set Password for Single User Mode on Linux (CentOS/RHEL)
Setting Password for Single User Mode in Linux adds security to Linux boxes. If someone accesses your server physically & reboots the server and then tries to change the root password from single-user mode. In that case, if the password is set on single-user mode, one has to first enter the root password, then only […]
Spacewalk Installation Steps On CentOS/RHEL
Spacewalk is an open-source configuration management tool sponsored by Red Hat. Spacewalk is an alternate of the Redhat network satellite server on Centos/Fedora/Scientific Linux. Spacewalk is the upstream project for the source of the Red Hat Network Satellite. It provides a management interface for software content across registered servers. Some of important Features of Spacewalk […]
Couldn’t find device with uuid [UUID] – LVM Not Active on Reboot
The Problem After a reboot the system will not start or activate one of the LVM volume groups. Trying to activate the group manually produces the message: Couldn’t find device with uuid ‘[UUID]’ The Solution The string LABELONE at the metadata location marks the device as being part of an LVM device. Without this string, […]
“VFS: Cannot open root device “UUID=[UUID]” or unknown-block(0,0)” – Booting issue CentOS/RHEL/OEL 6
The Problem Server fails to boot with latest kernel with the below errors from console logs: Initializing network drop monitor service md: Waiting for all devices to be available before autodetect md: If you don’t use raid, use raid=noautodetect md: Autodetecting RAID arrays. md: Scanned 0 and added 0 devices. md: autorun … md: … […]