Alen Komljen

Building and automating infrastructure with Docker, Kubernetes, kops, Helm, Rancher, Terraform, Ansible, SaltStack, Jenkins, AWS, GKE and many others.

Kubernetes upgrade – kubeadm

kubeadm is still in beta, but if you already deployed a Kubernetes cluster on some environment using it and now want to upgrade, you can do that manually. In some of previous posts, I wrote about Kubernetes deployment with kubeadm and it is available here https://crondev.com/kubernetes-installation-kubeadm. Currently kubeadm does not have support for cluster upgrade.

Reprovision on terraform apply

Terraform is a great tool for cloud provisioning and if you are not already I highly suggest to look into it. When cloud resources are already provisioned with Terraform sometimes we need to do reprovisioning, ideally each time we run terraform apply. That is not supported in Terraform, at least not yet. However, it has

ELK stack on Kubernetes

Having a good logging solution for almost any project is crucial. It is much easier to debug application logs. ELK (Elasticsearch / Logstash / Kibana) stack is popular among different platforms and often is a choice for in-house logging solution. Unlike Docker compose or Swarm, with Kubernetes we don’t have a possibility to specify logging

Kubernetes environment file

For all those who used docker-compose and similar tools, sometimes having environment files is crucial to keep docker-compose.yaml file organized and to make it easier to use and understand. When you move from docker-compose to Kubernetes you will probably search for this kind of feature. Prior to Kubernetes version 1.6, it was not possible to

Kubernetes installation with kubeadm

In my previous post, I presented an easy way how to deploy Kubernetes cluster with Rancher. Kubernetes is hard to install without using third party tools, but luckily they released an official tool for simple deployment kubeadm. Please note that kubeadm is still in Alpha and not ready for production use, but it is good

Docker orchestration with Kubernetes and Rancher

When it comes to Docker containers and orchestration there are a lot of available options. Almost every few months some new Docker orchestration tool is available. At least that was the case at the beginning. Most of those tools are opensource projects, but of course, there are some enterprise orchestration tools. However, Google’s Kubernetes is

Running Docker behind a proxy

When it comes to Docker and proxies, you will mostly not need them for running things locally or just to test something. However, we at Cron spend a lot of time managing production environments at corporations where everything is behind a proxy. Here in this post, I will share some basics and few tips on

SaltStack and Docker with reusable salt states

SaltStack can be used to provision almost anything. I also find it useful for provisioning of Docker containers and orchestration. However, with a lot of salt states, I’ve noticed that there are a lot of similarities in them. Salt states for building images are almost the same for every Docker image. The best solution I

Persistent PostgreSQL inside Docker

Most recommended way to persist data inside docker is to create data only container. However to simplify things it is also possible just to mount a directory from the host and to use that location as persistent storage. Also, this way it is easy enough to dockerize existing Postgres installations.