Enable HTTPS on Jenkins

Jenkins uses HTTP by default. You can enable HTTPS by performing a couple of steps. You need to acquire an SSL certificate and corresponding key for a domain that is under your control, and tell Jenkins that it needs to use these resources. Jenkins needs a password store to be able to use your SSL […]

Enable HTTPS on Gitlab

The Gitlab self-hosted application uses HTTP by default. You can enable HTTPS by performing a couple of steps. You need to acquire an SSL certificate and corresponding key for a domain that is under your control, and tell Gitlab that it needs to use these resources. Create a directory which will hold the certificate and […]

Monitoring hosts with CollectD, InfluxDB and Grafana

In this article we will install a monitoring solution on CentOS 7 consisting of CollectD, InfluxDB and Grafana. The first step is to install CollectD: yum -y install epel-release yum -y install collectd At the time of writing, this resulted in the installation of CollectD version 5.5.0. If you are using an older version of […]

Linux network auto shutdown from APC UPS

The APC Smart-UPS series of UPS devices allows you to power servers and switches when there is a power failure in the grid. When the UPS is running on batteries, you want your servers to be notified and properly shutdown. This article shows how you can accomplish that. We use the APC Smart-UPS X2200, with […]

Applying Innovative IT Modelling Methods to Low-level Grid Information for DSO Operations

I presented a paper called Applying Innovative IT Modelling Methods to Low-level Grid Information for DSO Operations at the PowerTech Eindhoven 2015 conference. Distribution system operators will gather an increasing amount of electricity data from the lower level of the grid to be able to cope with several challenges, such as an increase of distributed, […]

Dynamically Scaling Apache Storm for the Analysis of Streaming Data

I presented a paper called┬áDynamically Scaling Apache Storm for the Analysis of Streaming Data at the 1st International Conference on Big Data Service (IEEE BigDataService 2015). Stream processing platforms allow applications to analyse incoming data continuously. Several use cases exist that make use of these capabilities, ranging from monitoring of physical infrastructures to pre selecting […]

Fixing “Another operation involving the object is currently in progress” on XenServer

Sometimes XenServer does not allow you to shutdown or reboot a VM because “Another operation involving the object is currently in progress”. It would be nice to see what that operation is and be able to terminate the operation from XenCenter, but that isn’t the case yet. However, it is possible from the command line […]