Tuned is a set of tools and a daemon that tunes your system’s settings automatically depending on its usage. It periodically collects data from its components through plugins, which it uses to change system settings according to the current usage. You can find the system’s tuned profiles used in /lib/tuned/. When you create your own, […]
CentOS/RHEL 7
tuned-adm and Oracle
To offer the best possible performance right from the start, CentOS/RHEL 7 and 8 come with tuned. It offers a daemon that monitors system activity and provides some profiles. In the profiles, an administrator can automatically tune a system for the best possible latency, throughput, or power consumption. Based on the properties of an installed […]
“-bash: route: command not found” on CentOS/RHEL 7
The route command is used to show/manipulate the IP routing table. The simplest command with ‘route’ is to run it without any options or arguments which will return the IP routing table. The equivalent command with ip is as follows: $ ip r where r stands for route. The route command was deprecated in CentOS […]
‘error opening class fc_host’ – systool Command Error on CentOS/RHEL 7 and 8
The Problem When running the systool command on CentOS/RHEL 7, the following error message is reported: # systool -c fc_host -v Error opening class fc_host The Solution The error occurs because the scsi_transport_fc module that is responsible for populating the contents of /sys/class/fc_host/ directory is not loaded on the system. 1. Manually load the scsi_transport_fc […]
Dependency failed for NFS server and services
The Problem Attempting to start the NFS (nfs-server.service) on CentOS/RHEL 7 fails as follows: # systemctl status nfs-server.service nfs-server.service – NFS server and services Loaded: loaded (/usr/lib/systemd/system/nfs-server.service; enabled; vendor preset: disabled) Drop-In: /run/systemd/generator/nfs-server.service.d ‘-order-with-mounts.conf Active: inactive (dead) Mar 09 16:17:10 hostname systemd[1]: Dependency failed for NFS server and services. Mar 09 16:17:10 hostname systemd[1]: nfs-server.service: […]
How to Change Default Port of Apache On RHEL/CentOS 7
If you want to change Port in the Apache configuration file it’s easy to do. You can also run a website on a different port rather than the default port. 1. Let’s check which is listening to which service: # nmap -sT -O localhost 2. Check whether Port 8000 is free or not: # lsof […]
“cannot install the best update candidate for package” – error on running dnf update
The Problem Running the ‘dnf update’ command fails with below error: # dnf update Error: Problem 1: package perl-4:5.26.3-419.el8.x86_64 requires perl-interpreter(x86-64) = 4:5.26.3-419.el8, but none of the providers can be installed – cannot install both perl-interpreter-4:5.26.3-419.el8_4.1.x86_64 and perl-interpreter-4:5.26.3-419.el8.x86_64 – cannot install the best update candidate for package perl-interpreter-4:5.26.3-419.el8.x86_64 – cannot install the best update candidate […]
How To Configure sssd To Work With Multiple Active Directory Domains in Different Forests (CentOS/RHEL)
This post describes an approach to configuring sssd in order to interact with multiple Active Directory Domains located in different forests. This method involves altering /etc/krb5.conf and /etc/sssd/sssd.conf files. 1. Join the first domain (domain1.com) from the first forest. # realm join –verbose domain1.com -U LinuxAD@DOMAIN1.COM 2. Edit /etc/krb5.conf file and add the secondary domain […]
“error: Bind to port 2222 on 0.0.0.0 failed: Permission denied” – error while starting sshd service on CentOS/RHEL
The Problem On CentOS/RHEL, the OpenSSH SSH Daemon (sshd) utilizes port 22 for incoming connection requests from remote OpenSSH SSH (ssh) and Secure File Transfer (sftp) clients. In some cases, however, System Administrators prefer to utilize separate ports to service ssh and sftp activity. In One such case, system administrator is facing below error while […]
Configure MySQL Router to Auto Restart of Failure using systemd
The systemd unit file that ships with the MySQL Router 8.0 RPM’s will not automatically restart mysqlrouter on failure. It can be modifed to do so, though, by editing the file /usr/lib/systemd/system/mysqlrouter.service and adding this line: Restart=on-failure Put it right after the “ExecStart” line, so that the file ooks like this: [Unit] Description=MySQL Router After=syslog.target […]