OpenShift's oc debug and parallel execution

A colleague reported some issues in the OpenShift troubleshooting and diagnosis scripts at OpenShift-checks. Some time ago I did contribute some changes to use functions and allow using the RISU wrapper to the scripts, helping consuming the results via RISU’s HTML interface. As my colleague reported, for some plugins, the output of the command was not shown in the HTML Interface. After some investigation, it was found that parallel execution for the plugins was causing no output to be shown, but when filtering to individual ones via risu -i XXXXXXX/plugin -l it was working fine… the problem was not the check itself, as both of them worked fine when executed individually but failed when executing them together....

November 3, 2022 · 2 min · Pablo Iranzo Gómez

[Book] Red Hat Enterprise Linux 9 Administration

Last year, together with my colleagues Miguel and Scott, we released with the help of Packt team the RHEL8 Administration. During this one, with the collaboration of Pedro, a long-time colleague from the University LUG, we worked on the updated Red Hat Enterprise Linux 9 Administration book that it’s now available for preorder on Amazon. As with the previous version, the book targets users willing to learn skills to administer Red Hat Enterprise Linux or compatible systems....

October 12, 2022 · 1 min · iranzo

Setup a Quay mirror for offline installations with mirror-registry

In order to setup disconnected registry for installation, follow this blog post by Daniel at Introducing Mirror Registry for Red Hat OpenShift. At the end of the process it will output something like: INFO[2022-08-19 07:10:22] Quay installed successfully, permanent data is stored in /etc/quay-install INFO[2022-08-19 07:10:22] Quay is available at https://${HOSTNAME}:8443 with credentials (init, ${PASSWORDSTRING}) Once the setup is done, remember several steps: Edit /etc/containers/registries.conf to add relevant entries for our registry as required:...

August 19, 2022 · 2 min · Pablo Iranzo Gómez

RHCE and RHCSA tips and tricks

I did the RHCE exam some time ago, and still there are some tricks and advices I tell the people to bear in mind some of the things I used and that were also provided in the Red Hat Enterprise 8 Administration book: Don’t remember every step, it’s not effective, for example as I don’t recall syntax for BIND, I do remember package that has some files with examples and I use that one to check what I need to do Install mlocate and run updatedb as soon as you start, then you can use locate <file> to find out files in your system Use your preferred editor… it’s common to use vi or vim as it’s pretty standard, but if you’re used to another, make yourself comfortable in the system....

July 13, 2022 · 2 min · Pablo Iranzo Gómez

Unsupported upgrade for RHEL-based distributions without reinstallation

Most systems, based on RHEL, were not able to upgrade without reinstallation, or best said, not supported. The new version, that was released at around 18 months later contained so many changes that it was hard to test the upgrades themselves until leapp was introduced. Check the lifecycle here: https://access.redhat.com/support/policy/updates/errata However, the biggest problem could be the incompatibility of packages or package formats… but as usually there were some middle layers it was possible to upgrade without reinstallation by performing some manual steps....

April 23, 2022 · 15 min · Pablo Iranzo Gómez
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