Articles
"Resizing" a PVC and its PV in Microk8s
With the storage addon enabled, microk8s can automatically provision a PV when a PVC is created. The size of the PV is set according to that of the PVC. However, PVCs cannot be resized after creation. The PVC could be deleted and recreated with a larger size but this would result in the deletion of the PV and, by extension, all the data stored so far in it. This article presents a workaround to resize a PVC and its corresponding PV without any loss of data.
K8s NGINX Deployment for Ingress test
An NGINX container can be quite useful to test whether one's Kubernetes setup is working. Here is one example manifest file that deploys such container with an appropriate service and ingress.
Cert-manager Certificate Issuer
With cert-manager installed, SSL certificates can be automatically obtained for Ingresses deployed in a Kubernetes cluster. To achieve this, one must deploy the appropriate ClusterIssuers to the cluster. Here are example manifests to do so.
Encrypting Mosquitto using Certbot
This article presents how to encrypt a Mosquitto MQTT broker using SSL certificates obtained with Let's Encrypt
Getting Python's requests library to use a local DNS (Core-DNS, Docker-compose, etc.) while behind a proxy
When using Python's requests library, the requests are send through the proxy set as environment variables. Consequently, if the DNS to be used comes before said proxy, the host might not be resolved. This typically happens when resolving a host in Kubernetes using Core-DNS. If the request first leaves the Kubernetes cluster to reach the proxy, then the DNS server becomes unreachable, making the request fail.
Loading an Neo4J 3.X database in a Neo4J 4.X instance
Importing data from a Neo4J v3 database into a v4 one can be a hassle. Here are the steps to achieve the migration.
RESTful API design
There are four main kind of operations when working with a database: Create, Read, Update and Delete (CRUD). However, databases are usually not exposed directly to the clients. Instead, those operations are performed by a server side application with a client-facing API. The most common type of APIs nowadays are based on HTTP. An HTTP API can be built with complete freedom. However, guidelines for best-practice HTTP API design have been created. An API following those guidlines is called a REST (or RESTful) API.
Self-hosted GitLab instance for DevOps on Ubuntu 18.04
GitLab provides a great number of tools needed for the DevOps cycle of an application. In this guide, we'll install a GitLab instance on our own server and configure it to fit our DevOps needs. Here, we will use a fresh install of Ubuntu 18.04 as a base.
Deploying a TensorFlow model on a Jetson Nano using TensorFlow serving and K3s
The Nvidia Jetson Nano constitutes a low cost platform for AI applications, ideal for edge computing.However, due to the architecture of its CPU, deploying applications to the SBC can be challenging. In this guide, we'll install and configure K3s, a lightweight kubernetes distribution made specifically for edge devices. Once done we'll build and deploy an TensorFlow model in the K3s cluster.
Containerization of a Flask application
Flask can be seen as the equivalent of Express for Python. However, although an express application is basically production ready, a Flask app outputs the following when executed by itself: