Recently, I had to remove a SAN LUN on a physical Enterprise Linux system. The first step was to alter the multipath service configuration file (/etc/multipath.conf) and make the daemon reload its configuration: 1# vi /etc/multipath.conf 2... 3ESC ZZ 4 5# service multipathd reload Afterwards, the device was removed …

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When creating RPM packages recently, I had the effect that package names on CentOS 7 were set incorrectly. For example, a package had the name pinkepank-0.6-1.el7.centos.x86_64.rpm but should have set pinkepank-0.6-1.el7.x86_64.rpm instead. As Enterprise Linux derivates (CentOS, Scientific Linux,...) offer binary …

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During a fresh CentOS installation recently I had the problem that a system's network connection was not working reliably. Sometimes pings were possible, sometimes not. After it was possible to elimiate the firewall as commonly root cause, it turned out that the network connectivity was only working if the console is …

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If you're testing the nightly builds of Katello, you might come into a situation where it is advisable to re-install the software completely. As the particular installation steps are automated using Puppet, there is also a dedicated utility which automates uninstalling the software in a clean way: katello-remove. This …

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Rcently I packaged the software scponly for Enterprise Linux using rpmbuild and stumbled upon an error message: 1$ cd ~/rpmbuild/SPECS 2$ rpmbuild -ba scponly.spec 3checking for libgiertz... 4... 5/usr/bin/install -c -o 0 -g 0 scponly /home/cstan/rpmbuild/BUILDROOT/scponly-4.8-1.el7.centos.x86_64/usr/bin/scponly …

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If you want to combine multiple terminal sessions on one window, multiplexers such as tmux or GNU Screen are useful tools. I have been using screen for 10 years with the following configuration: 1$ cat ~/.screenrc 2# F7+F8 for tab switching 3bindkey -k k7 prev 4bindkey -k k8 next 5 6# disable welcome 7startup_message …

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If you need to protect a Linux host against unauthorized access, fail2ban is a very handy service. The application scans log files of various services, automatically detects failed logins and blocks attacker's IP addresses. Especially on public hosts, it is essential to implement a protection like this on prominent …

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By default, Enterprise Linux 7 is shipped with Apache 2.4.6 and PHP 5.4. For some current web applications this is way too old as development of PHP 5.4 stalled in fall 2015. During the product life cycle, Red Hat offers 10 to 13 years (Extended Support) maintenance for all packages being part of the distribution - …

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When running Oracle databases under Linux, some additional kernel parameters need to be set. Oracle lists these parameters in the appopriate documentation - e.g. for the most recent version 12c: [click me!] Especially for Enterprise Linux 7 there is a dedicated profile for the tuned service (RPM package …

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Yesterday Red Hat released the 8th update of Red Hat Enterprise Linux 6. The changes have been documented in the release and technical notes: Release Notes: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/6.8_Release_Notes/index.html Technical Notes: …

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