Ales Nosek - The Software Practitioner

Helping you navigate the world of Kubernetes.

Bootstrapping a Galera Cluster on RHEL7

The MariaDB Galera packages provided by the RDO project in their OpenStack repositories don’t seem to include a command or script to bootstrap the cluster. Let’s look at an alternative way to bring the cluster up.

Monitoring OpenStack Cluster with Icinga

If you don’t monitor it, it’s not in production! To get an OpenStack cloud ready for production, monitoring is a must. Let’s take a look at two projects providing Nagios/Icinga plugins for checking the health of OpenStack services.

Assigning Roles to Nodes Directly in RDO

RDO Manager defines multiple roles that nodes can play in OpenStack deployment. For large-sized installations, RDO features automatic assignment of roles to nodes. This assignment is based on the facts that RDO obtained about each node during the introspection. However, for smaller deployments, you might prefer to assign the roles to the available nodes by hand. It was not straight forward for me to find out about this manual option even when it is described in the TripleO documentation. Let’s review the required configuration steps in this blogpost.

Bridging VLAN Trunk to the Guest

In this article, we’re going to make an entire VLAN trunk on the host accessible to the guest machine. The guest machine can then create VLAN subinterfaces in order to access a particular VLAN.

Multiple RHEL Mirrors on a Single Machine

Reposync can mirror the yum repository to which your machine is subscribed to. However, you cannot subscribe your machine to the RHEL6 and RHEL7 at the same time. Let’s take a look at how Docker can help us here.

Improving Ansible’s ini_file Module

Update 3/31/2016: The implementation of the ini_file module described in this blogpost has been merged into Ansible version 2.0.

For editing Windows INI files, Ansible comes with an ini_file module built in. Unfortunately, this module uses Python’s ConfigParser module which reformats the entire INI file whenever you want to change a single line. It removes all the comment lines, too. For me this was not acceptable. After looking for a possible solution I decided to improve the ini_file module and created ini_file2. I realized how easy it is to create an Ansible module.

Browsing Docker Source using Eclipse

Do you like Docker technology and want to learn more about it? There’s no better way to learn than reading the source code. In this article, we’ll install the Go programming language, download the latest Docker source code and navigate through it in Eclipse.

Running Wine within Docker

After upgrading to Debian Jessie, my Windows application running under Wine stopped working. In this article we’ll use Docker to restore the Wine environment from Debian Wheezy. We’ll run the Windows application inside this Docker container.