Test your deployments locally with minikube

A chapter of the courses that I give demonstrates how easy it is to implement a multi-tier application on Rancher / Kubernetes (thanks to the Rancher Catalog). The recipe is the same, whether you are on Rancher 1.x or 2.0! The exercise also uses a storage driver that allows application deployment with persistent storage.

My application is on Github, it is simply an application in Node.js with a MongoDB backend, which displays “Hello MyApp from MongoDB!” in the browser when it is called on the route /myapp. To familiarize yourself a bit with Kubernetes, I decided to deploy this application directly on a cluster, with CLI.

You can use any K8s cluster, a deployed with Rancher, or with kubeadm (see my previous blog), or do it locally with kinikube. This is the last option that I chose because it allows to test our deployment locally. For the installation of minikube and kubectl, I invite you to read this tutorial.

If I consider that my application is a MongoDB backend and a Node.js frontend, what will I need in K8s? First of all a volume for persistence. With minikube, I use local storage. A volume claim, to make this volume available to MongoDB. A MongoDB deployment. One service, to make MongoDB available to other third parties. Another deployment for Node.js, as well as its service. And finally an ingress rule to access my application outside my cluster. I will even push the vice a little further by using a configMap for my Node.js environment varaibles (MongoDB URI). Ready?

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Setup a secured redis-cluster on centos7

Setup a secured redis-cluster on centos7

What is redis exactly?

Redis is an open source (BSD licensed), in-memory data structure store, used as a database, cache and message broker.

Redis Sentinel provides high availability for Redis. In practical terms this means that using Sentinel you can create a Redis deployment that resists without human intervention to certain kind of failures.

⚠️ You need at least three Sentinel instances for a robust deployment.

Sentinel constantly checks if your master and slave instances are working as expected.

If a master is not working as expected, Sentinel can start a failover process where a slave is promoted to master, the other additional slaves are reconfigured to use the new master, and the applications using the Redis server informed about the new address to use when connecting.

ℹ️ Sentinel manages the failover, it doesn’t configure Redis for HA. It is an important distinction.

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Ansible – how to collect information about remote hosts with Gathers facts

 Anisble – how to collect information about your remote hosts

In order to do so, we will discuss about ansible modue: Gathers facts

:information_source: Official webpage: https://docs.ansible.com/ansible/setup_module.html

Display facts from all hosts and store them at /tmp/facts indexed by hostname

ansible all -m setup --tree /tmp/facts

➡ now check the file to have a clear view off all variables (facts) collected by ansible for your host like the well known {{ inventory_hostname }}

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Usefulness of an MQ layer in an ELK stack

Usefulness of an MQ layer in an ELK stack

First things first, disambiguation; let’s talk about these strange words.

What does ELK means?

An ELK stack is composed of Elasticsearch, Logstash, and Kibana; these 3 components are owned by the elastic.co company and are particulary useful to handle Data. (ship, enrich, index and search your Data)

What does MQ means?

In computer science, The message queue paradigm is a sibling of the publisher/subscriber pattern.
You can imagine an MQ componant works like several mailboxes; meaning that publisher(s)/subscriber(s) do not interact with the message at the same time, many publishers can post a message for one subsriber and vice versa.

➡ Redis or Kafka or RabbitMQ can be used as buffer in the ELK stack.

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Package manager tools for Debian like


The needs are simple, create local repository and mirror the official one for Debian like systems.

RedHat like systems got multiple, Debian like, well not so much.

In this case we need to manage Ubuntu servers, well Canonical has Landscape, but we want to keep it simple.

The possibilities

For Debian Like there’s 2 possibilities :

  • aptly which can seems to be integrate with ansible
  • pulp_deb which is a community project to add to an installation of Katello/Pulp

Persistent volumes with Rancher/Kubernetes on AWS

Volume persistence in Kubernetes (and other orchestrators) is in full swing, and for good reason, Kubenetes is no longer satisfied today to be a stateless runtime environment, but also and more often stateful … Let’s see how with Rancher and AWS we may have volumes provisioned automatically.

High level architecture on AWS

For this blog I use a single group of ec2, all in the same security group, which allows all traffic between instances.

I’ve bootstrapped ec2 instances with the last RancherOS version available on AWS, which is currently v1.0.2.

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Hosman-Lemeshow in Python

Test a model before putting it into production and verify that the model we have assumed is correctly specified with the right assumptions. In this article I present a method to test its model: the test of Hosmer-Lemeshow.

To perform the Hosmer-Lemeshow test, you’ll need a dataset.


This dataset contain relevant information about the scored for people who wants a credits.

First, we need to load the dataset from the CSV file to a new Python dataframe with the Pandas library.

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Hands on Kubernetes with kubeadm

Passionate for Docker? Curious to learn more about Kubernetes, the Google orchestrator? Kubeadm is the solution! Kubeadm is a new tool to deploy painlessly kubernetes on Centos 7, Ubuntu 16.0′ or even Hypriot v1.0.1 on RPi! To learn more about kubeadm: http://kubernetes.io/docs/getting-started-guides/kubeadm/

In this technical blog, I’ll show you how to:

  • Create four ec2 instances on AWS with Centos 7.2
  • Install Docker on Centos with LVM devicemapper
  • Install Kubernetes and Kubeadm on each instance
  • Run your Master and join with the minion
  • Launch your first nginx Pod
  • Create your first Replication Controller
  • Expose your Replication Controller  with a Load Balancer Service

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Introducing the Rancher Partner Network

on Oct 18, 2016

This morning, we’re excited to follow on the launch of the Rancher Partner Network – a group of leading organizations focused on building top-notch cloud and container solutions for their customers. These are vendors with whom we collaborate, and whom we trust and endorse to help enterprises bring containers into their development workflows and production environments. The Rancher Partner Network includes consulting partners, systems integrators, resellers, and service providers from the Americas, Europe, Asia, and Australia.
Rancher Partners

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FinTechMeets: Unlocking the Power of Big Data

FinTechMeets: Unlocking the Power of Big Data

How harnessing big data & machine learning will change the face of business

Yesterday, on September 22, 2016, lux future lab held its second FinTechMeets at BGL BNP Paribas in Kirchberg, focusing on what has become a hot topic: big data and how to harness it.

Roughly 350 IT and financial professionals attended the lunchtime gathering, which centered on a global overview of big data, machine learning and their practical applications.

Jonathan Basse, Founder of Data Essential, and Jed Grant, CEO & Founder of KYC3, shared their insights based on years of experience developing solutions that access this wealth of information.

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