handle kvm static ip adresses

Nov. 27, 2018    Tags: kvm  virsh

I did a lot of work with libvirt and kvm and for some hosts I wanted to have a fixed IP address but not configured on the host itself. I wanted to get it from dhcp.

Minikube increase disk size

Sept. 10, 2018    Tags: docker  testing  kubernetes  minikube

None

I did some more research and development with kubernetes and minikube. During some tests where the diskspace of one node got bigger than 16GB and I saw a message about DiskPressure in the logs, I figured out that minikube has a default disksize of something around 16GB.

Check if a file was changed in a bash script

Aug. 3, 2018    Tags: unix  debian  letsencrypt  bash

I’m using letsencrypt for most of my servers. One of these servers is behind a firewall without any direct internet connection. Therefore I’m not able to use letsencrypt or dehydrated directly on that server. I’m copying the certificate to a specific location as a normal ssh user and on that host itself I have to check if the certificate was changed to reload the webserver.

Puppet could not retrieve catalog...

July 28, 2018    Tags: puppet

Some days ago I got an error on one of my puppet agents which I can’t really explain. Everytime I executed my puppet agent (puppet agent -t -d) I got the following error:

Could not retrieve catalog from remote server: \ Could not intern from text/pson: "\xC2" on US-ASCII

pm-suspend on Ubuntu

Nov. 2, 2017    Tags: pm-utils  pm-suspend

After upgrade to Ubuntu 16.04 I recognized that pm-utils are not used anymore to suspend/resume my notebook. The change was already done with Ubuntu 15.04, but I haven’t recognized it before, because everything was working like expected. I recognized it these days after I changed my windowmanager to i3wm.

Since Ubuntu 15.04 they don’t use the pm-utils like pm-suspend any more. They use now systemctl commands to suspend if the lid is closed. Therefore my screenlock was not working any more and I had to adapt some things to get the i3 screenlocker i3lock ...

How to use grafana scripted dashboards

Oct. 17, 2017    Tags: prometheus  dashboard  grafana

I’m using prometheus to collect metrics of java applications or unix systems. On top I configured grafana just to have a nice an shiny view and to get the possibility to add dashboards and to save my graphs somehow. Grafana is pretty nice to add graphs in a fast way to new dashboards, but what happens if you have, like I have, a lot of metrics which change or new hosts are getting added. That’ something you don’t want to do by hand. Therefore grafana implemented the “scripted dashboards”. I figured out, that the documentation of these dashboards ...

How to disable debian 9 private tmp

Oct. 9, 2017    Tags: debian  systemctl  systemd

These days I upgraded one of my hosts with debian jessie to the latest debian stretch. After that upgrade I figured out, that some of my nagios checkes were red and also my django wsgi applications were not able to read from system tmp any more. The main reason for that is, that with debian 9, some processes which uses systemd forced the private tmp directories.

Export Dropwizard Metrics to Prometheus

Aug. 15, 2017    Tags: metrics  prometheus  dropwizard

Prometheus, one of the leading open-source monitoring solutions at the moment. It is written in Go, therefore fast and scalable. It is configurable with simple textfiles which makes it easy to be maintained via puppet. It comes with a lot of out of the box clients.

But in the end, how can we get metrics from a java application. Or more detailed, how can we get metrics from a self written java application which already has some kind of metrics collector like the dropwizard metrics?