Posts

How to expand VM memory, CPU and disks

In this article we’ll cover three practical cases for expanding resources in a VM managed with libvirt/KVM: Increase the number of vCPUs (cores) Increase RAM memory Expand disk and filesystem inside the guest We’ll use virsh commands, libguestfs tools where applicable, and standard utilities inside the guest (growpart, resize2fs, xfs_growfs, LVM). I’ll include “hot” methods when the system supports them and safe cold alternatives. Note: To run without sudo, your user must belong to the libvirt and kvm groups.

Thursday, October 16, 2025 | 4 minutes Read

06 - Create domains, projects, users and roles in OpenStack

Identity (Keystone) is OpenStack’s authentication and authorization service. In this step I prepare the minimal Identity configuration we need to continue the installation and to test OpenStack. Although the default domain already exists after keystone-manage bootstrap, I explicitly create the projects and users we use in the guides: service (for service users) and demo (for non‑admin user tests). I also create an example role and assign it to the demo user.

Sunday, November 23, 2025 | 2 minutes Read

07 - Install and configure Glance

At first glance, Glance may seem simple: it stores, manages, and serves images to the compute service (Nova). In this post I install and configure Glance on the controller01 node, explain key components, and leave a minimal flow to upload a test image. Glance architecture Components you’ll see during installation: Glance API: exposes the REST API to store, list, and retrieve images. Glance Store: manages backends where image files are stored (file, Swift, Ceph, …). Metadata / registry service: stores image metadata (in many deployments this functionality is integrated into the API and DB). Glance uses an SQL database for state, here we use MySQL/MariaDB on the controller. In this guide we use the file backend for simplicity.

Sunday, November 23, 2025 | 2 minutes Read

How to create a Debian 13 virtual machine template

A virtual machine template is a preconfigured OS image that we use to quickly deploy new VMs, avoiding repetitions and errors. Here we’ll see how to create a Debian 13 master template ready for cloning. 1 Create and install the base VM Create a clean Debian 13 VM, apply all updates and add the common software you want on all clones (guest agent, utilities, etc.). Minimal example: # Create the base VM (adjust CPU, RAM, disk, ISO and network to your environment) virt-install \ --name debian13-base \ --memory 4096 \ --vcpus 2 \ --disk path=/var/lib/libvirt/images/debian13-base.qcow2,size=20,format=qcow2 \ --cdrom /var/lib/libvirt/images/debian-13.1.0-amd64-netinst.iso \ --os-variant debian12 \ --network network=default,model=virtio \ --noautoconsole Once the VM is created, install all the components you want this template to have: users, packages, etc.

Saturday, October 18, 2025 | 6 minutes Read

08 - Configure Placement in OpenStack

Placement tracks available physical resources and helps Nova schedule allocations. In this guide I will install and configure Placement on controller01 using Ubuntu packages and provide the minimal steps to verify it. Prerequisites Before starting, make sure you have: Keystone installed and reachable. A MySQL/MariaDB database available. Administrative credentials (admin-openrc) to create users and services. Create the database Connect to the database server as root to create the Placement database:

Sunday, November 23, 2025 | 2 minutes Read

09 - Install and configure Nova on the controller node

This document describes how to install and configure the Compute service (Nova) on the controller node (controller01). Prerequisites Before starting, make sure you have the basic Keystone credentials and databases created (admin-openrc available). Create the databases (on controller01) Connect to the SQL server as root to create the necessary databases: vagrant@controller01:~$ sudo mysql Create the nova_api, nova, and nova_cell0 databases: CREATE DATABASE nova_api; CREATE DATABASE nova; CREATE DATABASE nova_cell0; Grant permissions to the nova account (replace NOVA_DBPASS with your password):

Sunday, November 23, 2025 | 3 minutes Read

Basic Auth in Kong

Basic Authentication may seem like a trivial mechanism because it only uses a username and a password. However, using it correctly means separating three ideas: the HTTP standard, the validation performed by Kong Gateway, and the identity that Kong associates with valid credentials. In this article we will look at those three layers and build a reproducible lab with Kong Ingress Controller. The goal is not simply to copy files and blindly apply them. First we will understand what each resource represents, then we will apply it, and finally we will check what happens inside Kong.

Sunday, July 26, 2026 | 8 minutes Read

10 - Install and configure Nova on compute nodes

On this page I configure a compute node (for example compute01) so it can run instances with Nova. I use QEMU/KVM when the hardware supports it, if not, I configure pure QEMU. Before starting, make sure you have: Added the controller name and IP in /etc/hosts on the compute node. Service credentials (admin-openrc) and access to the database server. Install and configure the components (on the compute node) vagrant@compute01:~$ sudo apt install nova-compute -y Edit /etc/nova/nova.conf and point the connection strings to the controller databases:

Sunday, November 23, 2025 | 2 minutes Read

Key Auth in Kong

An API key may look like little more than a random string that a client adds to every request. To use it correctly, however, it helps to separate three ideas: the credential presented by the client, the validation performed by Kong Gateway, and the identity of the Consumer associated with that credential. This article covers those three layers and builds a reproducible lab with Kong Ingress Controller. We will first understand each resource, then apply it, and finally verify what happens inside Kong.

Sunday, July 26, 2026 | 8 minutes Read

11 - Configure Neutron on the controller node

This page installs and configures the Neutron networking service on the controller node (controller01). Neutron manages virtual networks, routers, subnets, and other networking components for instances. Prerequisites Before starting, ensure you have: Keystone installed and reachable. A MySQL/MariaDB database available. Administrative credentials (admin-openrc) to create users and services. Create the database Connect to the database server as root to create the Neutron database: Access the SQL client: vagrant@controller01:~$ sudo mysql Create the neutron database: MariaDB [(none)]> CREATE DATABASE neutron; Grant privileges to user neutron (replace NEUTRON_DBPASS with your password): MariaDB [(none)]> GRANT ALL PRIVILEGES ON neutron.* TO 'neutron'@'localhost' \ IDENTIFIED BY 'NEUTRON_DBPASS'; MariaDB [(none)]> GRANT ALL PRIVILEGES ON neutron.* TO 'neutron'@'%' \ IDENTIFIED BY 'NEUTRON_DBPASS'; Exit the client when finished. Create the user and service endpoints Load your admin credentials to work with the OpenStack CLI:

Sunday, November 23, 2025 | 4 minutes Read

HMAC Auth in Kong

HMAC Authentication proves that a request was created by a client that knows a shared secret without sending that secret in the request. In addition to authenticating the client, the signature detects changes to the signed elements while they are in transit. This article explains how an HMAC signature is built and validated by Kong Gateway, and how the Consumer relates to its credential. We then build a reproducible Kong Ingress Controller lab and protect /hmac-auth.

Sunday, July 26, 2026 | 7 minutes Read

12 - Configure Neutron on compute nodes

On this page, we configure Neutron on the compute node (compute01). The compute node manages network connectivity and security groups for the instances that run on it. Prerequisites Make sure you have completed all previous posts before starting. Install the components vagrant@compute01:~$ sudo apt install -y neutron-linuxbridge-agent Configure the common component Edit /etc/neutron/neutron.conf to configure authentication and the message queue. In [DEFAULT], configure access to RabbitMQ and the authentication strategy:

Sunday, November 23, 2025 | 3 minutes Read