MySphere

openshift

Configure Haproxy as a load balancer for Openshift 4.16

07 Feb, 2025

I set up an OpenShift 4.16 cluster using UPI on top of VMware. The cluster has 3 Masters, 3 Worker Nodes, and 3 InfraNodes. The infra nodes were necessary to install IBM Storage Fusion. After the setup, I needed to create a load balancer in front of the OpenShift cluster. There are several options, and one of them is HAProxy. I just installed an RHEL 9 server, added 3 ips to the network card and setup the haproxy. Prerequisites - A system running RHEL 9 - Root or sudo privileges - A basic understanding of networking and load balancing Step 1: Install HAProxy First, update your system packages: sudo dnf update -y Then, install HAProxy using the package manager: sudo dnf install

06 Feb, 2025

The watch command is a useful utility in Unix-like systems that allows you to execute a command periodically and display its output. However, macOS does not come with watch pre-installed. If you're running macOS Sequoia and want to use watch, follow the steps below to install it. Recently i switch my mabook to a new MacBook Pro M2 and try to use the command to watch some openshift logs and i got the following result: !(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAA6gAAAC6CAYAAACjt2AlAAAAAXNSR0IArs4c6QAAAJBlWElmTU0AKgAAAAgABgEGAAMAAAABAAIAAAESAAMAAAABAAEAAAEaAAUAAAABAAAAVgEbAAUAAAABAAAAXgEoAAMAAAABAAIAAIdpAAQAAAABAAAAZgAAAAAAAACQAAAAAQAAAJAAAAABAAOgAQADAAAAAQABAACgAgAEAAAAAQAAA6igAwAEAAAAA

openshift

Manage OpenShift virtual machines with GitOps

04 Feb, 2025

Managing virtual machines in an Infrastructure as Code (IaC) environment requires efficiency and reliability. One of the central ideas for this is having a single source of truth (SSoT) in order to ensure consistency in resources, improve automation, and leverage processes such as version control. In this type of secluded environment, we can track and test changes and increase our scalability with ease. This learning path will showcase how to use Red Hat OpenShift GitOps with a Git repository as a single source of truth for our infrastructure, thereby enhancing automation, consistency, and efficiency for VMs in Red Hat OpenShift Virtualization. https://developers.redhat.com/learn/manage-op

machine-learning

Free Machine Learning Book

04 Feb, 2025

Understanding Machine Learning, by Shai Shalev-Shwartz and Shai Ben-DavidPublished 2014 by Cambridge University Press PDF of manuscript posted by permission of Cambridge University Press.Users may download a copy for personal use only. Not for distribution. https://www.cs.huji.ac.il/w~shais/UnderstandingMachineLearning/understanding-machine-learning-theory-algorithms.pdf(https://www.cs.huji.ac.il/w~shais/UnderstandingMachineLearning/understanding-machine-learning-theory-algorithms.pdf)

openshift

How to remove a worker node from Red Hat OpenShift Container Platform 4 UPI?

28 Jan, 2025

When you delete a node using the CLI, the node object is deleted in Kubernetes, but the pods that exist on the node are not deleted. Any bare pods not backed by a replication controller become inaccessible to OpenShift Container Platform. Pods backed by replication controllers are rescheduled to other available nodes. You must delete local manifest pods. - To delete the node from the UPI installation, the node must be firstly drained and then marked unschedulable prior to deleting(https://access.redhat.com/bounce/?externalURL=https%3A%2F%2Fdocs.openshift.com%2Fcontainer-platform%2Flatest%2Fnodes%2Fnodes%2Fnodes-nodes-working.html) it: $ oc adm cordon $ oc adm drain --force --delete-loca

openshift

Isolating Infrastructure Nodes

24 Jan, 2025

Applying a specific node selector to all infrastructure components will guarantee that they will be scheduled on nodes with that label. See more details on node selectors in placing pods on specific nodes using node selectors(https://access.redhat.com/bounce/?externalURL=https%3A%2F%2Fdocs.openshift.com%2Fcontainer-platform%2Flatest%2Fnodes%2Fpods%2Fnodes-pods-node-selectors.html), and about node labels in understanding how to update labels on nodes(https://access.redhat.com/bounce/?externalURL=https%3A%2F%2Fdocs.openshift.com%2Fcontainer-platform%2Flatest%2Fnodes%2Fnodes%2Fnodes-nodes-working.html%23nodes-nodes-working-updatingnodes-nodes-working). Our node label and matching selector for

openshift

Infrastructure Nodes in OpenShift 4

23 Jan, 2025

Infrastructure nodes allow customers to isolate infrastructure workloads for two primary purposes: 1. to prevent incurring billing costs against subscription counts and 1. to separate maintenance and management. This solution is meant to complement the official documentation(https://access.redhat.com/bounce/?externalURL=https%3A%2F%2Fdocs.openshift.com%2Fcontainer-platform%2Flatest%2Fmachinemanagement%2Fcreating-infrastructure-machinesets.html) on creating Infrastructure nodes in OpenShift 4. In addition there is a great OpenShift Commons video describing this whole process: OpenShift Commons: Everything about Infra nodes(https://access.redhat.com/bounce/?externalURL=https%3A%2F%2Fyoutu.be

openshift

Is it possible to change the domain name of OpenShift 4 cluster post installation?

14 Jan, 2025

It is not possible to change the domain for the API, internal or external. Starting with OpenShift 4.8, it is possible to change the domain of the console and downloads routes after cluster installation. Choose your domain name with carrefully. More information see this document from RedHat https://access.redhat.com/solutions/4853401(https://access.redhat.com/solutions/4853401)

linux

rsync is faster than scp to copy files between machines

31 Dec, 2024

rsync is generally faster than scp for copying files, especially when transferring a large amount of data or syncing directories. Here's why: 1. Incremental Transfers - rsync: Only transfers the parts of files that have changed, rather than the entire file. This makes subsequent transfers much faster. - scp: Always transfers the entire file, even if only a small part of it has changed. 2. Compression - rsync: Supports compression during the transfer (using the -z option), which reduces the amount of data sent over the network. - scp: Also supports compression (using the -C option), but it doesn't have the same efficiency in skipping unchanged data. 3. Resume Support - rsync: Can

linux

OpenMediaVault error when try to mount a shared folder

30 Dec, 2024

I follow the instructions to create and share a folder on OMV but i can't access the shared folder using my MAC or Linux Manchines. On the Mac i got the error : The operation can't be completed because the original item for "foder name" can't be found. When i try to mount the shared folder on a Linux machine i got Permission Denied. I discovered that only the first user created during the initial setup can access the shared folders. I opened a terminal session and ssh to the omv machine. The permissions for the disks are shown bellow: !(https://www.mysphere.com.br/wp-content/uploads/2024/12/image.png) The failed disk have the permission drwx----- The only way i found was to change the

13 Dec, 2024

Yesterday i was helping a customer to deploy his OpenShift 4.16.x cluster. The first step was the bastion host preparation. This includes the setup of the OCP CLI. We do the default instalation of the CLI on top of RHEL 8.x but after the installation we got the following error: oc version oc: /lib64/libc.so.6: version GLIBC2.33' not found (required by oc) oc: /lib64/libc.so.6: version GLIBC2.34' not found (required by oc) oc: /lib64/libc.so.6: version GLIBC2.32' not found (required by oc) We tried to compile the new GLIBC .but without success. The solution: Download the CLI version compiled for RHEL 8. Link here(https://access.redhat.com/bounce/?externalURL=https%3A%2F%2Fmirror.opensh

openshift

CPU Throttling in Kubernetes

28 Nov, 2024

In the context of a Kubernetes cluster, CPU throttling still refers to the process of limiting the amount of CPU time a container or pod can use, but it's slightly different than throttling within an individual CPU or device, as Kubernetes manages resources at the container level. Here’s a breakdown of how CPU throttling works in a Kubernetes environment: 1. CPU Resources in Kubernetes Kubernetes allows you to specify how much CPU a container can request and how much it is allowed to consume. This is done through resource requests and limits: - CPU Request: The minimum CPU resource that the container is guaranteed to have. - CPU Limit: The maximum CPU resource the container can use. Ku