Nowadays there are very few use-cases where bare metal should be preferred over virtualisation.

Linux professionals should have a thorough understanding of virtualization under Linux: Linux is a very good platform when it comes to virtualizing systems, enabling virtualisation even using simple suites such as libvirt with KVM. Figure out that even VMWare relied on Linux: the early version of its hypervisor, called ESX, included a Linux kernel, and there are several full-featured products, such as Red Hat’s RHEVM and Oracle’s VM, that still relies on it.

Virtualisation provided a great deal of resilience, but also added some complexity that professionals should be able to deal with: it speculates that the average resources consumption is far less than the sum of the provisioned capacity, but spikes happens, and professionals should know how to cope with them. Professionals should be able to design and implement 24×7 resilient virtualisation infrastructures, and be able to maintain and quickly troubleshoot them when issues arises.

Besides exploiting virtualisation to create virtual infrastructures, professionals should know how to take advantage of the power and resilience provided by virtualisation, for example to be able to quickly mock-up virtual environments to test what they are working onto, or to provide the required infrastructure to launch automated integration tests.

This requires the knowledge of automation tools targeted to manage virtualized environments such as Vagrant.

Kubernetes Prometheus And Grafana With kube-prometheus-stack

Posted on November 27, 2024November 30, 2024 by Marco Antonio Carcano

When using Kubernetes, it is mandatory to collect performance metrics so as to be able to plot them into meaningful graphs (a must-have during troubleshooting), visualize alerts in dashboards and get email notification of critical events. The best practice is to deploy Prometheus, Grafana and Alertmanager.

In the "Kubernetes Prometheus And Grafana With kube-prometheus-stack" post we see how to easily deploy and setup these three amazing components to setup a full featured alerting and performance monitoring solution.

The post also shows how to deploy additional Grafana Dashboards and how to deploy custom Prometheus rules to trigger application specific alerts.

NetApp Astra Trident Tutorial NFS Kubernetes CSI HowTo

Posted on November 20, 2024 by Marco Antonio Carcano

NetApp is certainly one of the most popular storage brands, with quite a big portfolio of cost-effective storage solutions. With the spreading of Kubernetes, they developed Trident, their own Container Storage Interface (CSI) compatible storage orchestrator.

In the "NetApp Astra Trident Tutorial NFS Kubernetes CSI HowTo" we see how easy it is to deploy and set it up.

RKE2 Tutorial – RKE2 Howto On Oracle Linux 9

Posted on November 6, 2024November 20, 2024 by Marco Antonio Carcano

Kubernetes is certainly the most popular and probably the best solution for orchestrating containerized workloads, but maintaining its vanilla distribution is certainly a challenge, so you must carefully guess pros and cons in terms of maintenance costs and operational risks.

A very cost effective and interesting alternative to running the vanilla Kubernetes is the "Rancher Kubernetes Engine 2" (RKE2), a certified Kubernetes distribution focused on security to adhere to the U.S. government’s compliance requirement. RKE2, besides providing a reliable Kubernetes distribution, smoothly integrates with Rancher.

In the "RKE2 Tutorial - RKE2 Howto On Oracle Linux 9" post we see it in action, installing a highly available multi-master Kubernetes cluster, exposing the default ingress controller using MetalLB for providing Load Balancing services.

Rancher Tutorial – Rancher Howto Install On Oracle Linux 9

Posted on October 29, 2024November 14, 2024 by Marco Antonio Carcano

Rancher is a complete software stack for managing multiple Kubernetes clusters either on a public cloud or on premises. With the first stable release issued in 2016, it has slowly improved its feature set and become more and more popular. Currently it is probably the best option for managing Kubernetes clusters.

In the "Rancher Tutorial - Rancher Howto Install On Oracle Linux 9" post we see it in action learning how to to quickly deploy and install it on a Oracle Linux 9 platform, so to be able to immediately start playing with it and learning how this amazing tool can really simplify your life when dealing with Kubernetes.

High Available HA Proxy Tutorial With Keepalived

Posted on October 3, 2024November 14, 2024 by Marco Antonio Carcano

HAProxy is certainly one of the most blazoned, fast and efficient (in terms of processor and memory usage) open source load balancer and proxy, enabling both TCP and HTTP-based applications to spread requests across multiple servers. In the "High Available HA Proxy Tutorial With Keepalived" we see not only how to install it in a High Available fashion, but also how to set the configuration in a clean and tidy way, having it automatically fetched from a Git remote repository.

Setup a GENEVE tunnel with OpenVSwitch and Podman

Posted on December 12, 2023November 14, 2024 by Marco Antonio Carcano

Overlay networking enables to implement tunnels to interconnect networks defined inside a host (such as Docker/Podman private networks): for example flannel based Kubernetes uses VxLANs to interconnect the Minion’s private networks. Anyway VxLAN is only one of the available technologies: other technologies such as GENEVE, STT or NVGRE are available.

In this post we setup a GENEVE tunnel with OpenVSwitch and Podman - the described set up goes beyond the simple interconnection on of layer 3 network segments, interconnecting two Podman’s private networks configured with the same IP subnet (so they share the same broadcast domain) - the layer 2 data are exchange between the OpenVSwitch bridges on the two hosts through the GENEVE tunnel.