Oracle Linux

The yum(Yellowdog Updater Modified) service is an automatic update tool to update the system each day. You can use both up2date/yum on Oracle Enterprise Linux/ Oracle Linux. Yum uses a configuration file at /etc/yum.conf. Additional configuration files are also read from the directory set by the reposdir option (default is ‘/etc/yum.repos.d’). Yum is an automatic […]

Question: How to change timezone in CentOS/RHEL 7 server from EST to CST. Follow the below steps to change the timezone to CST. (Execute the below commands as root user) 1. List all the available timezones using the below command: # timedatectl list-timezones 2. Locate the correct timezone you need that is in the central […]

Question: How to change the password policy on a system so that a user cannot choose any of the last 3 passwords previously used? 1. Make sure that the file /etc/security/opasswd has the default permission (600). # ls -l /etc/security/opasswd -rw——- 1 root root 116 Sep 8 14:52 /etc/security/opasswd 2. Ensure you backup the file […]

The Problem Some user directories cannot be deleted. For example: /root/.cache/doc/ directory /root/.cache/doc/by-app directory If we try to delete the directory, we get the below error: # rm -rf /root/.cache/doc/ rm: cannot remove ‘doc/by-app’: Function not implemented The Solution The directories are the mount points for /dev/fuse device. # mount –mount (ext, ocfs2, nfs, gfs, […]

The Problem Trying to login via SSH, the session hangs. Adding “-vvv” option, shows that it hangs with below messages: debug1: expecting SSH2_MSG_KEX_ECDH_REPLY The Solution MTU was set to 9000 : # ip add| grep -i eth0 2: eth0: mtu 9000 qdisc pfifo_fast state UP group default qlen 1000 inet x.x.x.x/24 brd x.x.x.x scope global […]

The Problem Under /etc/systemd/system the mount unit file was created with name “test.mount”. The mount point directory created is /home/test. Under the mount unit file options in the “Where=” the mount point configured is /home/test. The device where the filesystem will be mounted is /dev/xvdb1 and it was defined under “What=” option. When configuring mount […]

Disabling lvm2-lvmetad.socket/service on CentOS/RHEL 7 system works while the system is running, but after a reboot, it comes up again. This post will show you how to prevent this from happening. 1. Modify the /etc/lvm/lvm.conf file with your favorite file editor, like vi or nano, and switch the value of “use_lvmetad = ” from 1 […]

The scope of this post is to explain the steps involved in increasing the /boot filesystem, when no sufficient space available to install new kernel package. Though we have standard methods to reduce the size of /boot i.e. removing unused kernel and image files from boot, as an alternate approach, this post illustrate the steps […]

On a CentOS/RHEL 7, the network interface will be named like enoxxx. This post provides steps on how to disable such “Predictable Network Interface Device Names”. We can use the following ways to disable the predictable network interfaces: 1. Create your own manual naming scheme by defining your own udev rules file in /etc/udev/rules.d folder […]