Author Archives: George Valentin Voina

#DevOps the new hype at #DevTalks Cluj

By | May 20, 2017

It seems that now I have a name for what I have doing for the last 15 years 🙂 I attended a a DevTalks conference and the hype of the day was the DevOps idea. According to the wiki definition: DevOps (a clipped compound of “software DEVelopment” and “information technology OPerationS”) is a term used… Read More »

Blog Links: #Java SE support for #Docker CPU and memory limits

By | May 26, 2017

A very important release announced in a post on the Oracle blog. Java SE support for Docker CPU and memory limits In short: “As of Java SE 8u131, and in JDK 9, the JVM is Docker-aware with respect to Docker CPU limits transparently.” SET 1: If -XX:ParalllelGCThreads, or -XX:CICompilerCount are not specified as command line… Read More »

Blog Links: Best #Docker related posts of the month

By | May 4, 2017

The number of uses and posts related to Docker is huge. The problem is the clutter is also big so finding the relevant posts is hard. Bellow is a selection of posts that got my attention. First I have to mention the official Docker blog where the curated list of posts about docker are posted… Read More »

Linux Cluster with #DRBD replication: solving “HA LVM requires Only one logical volume per volume group” issue

By | April 24, 2017

I have a RHEL 6 Linux cluster setup where the main database storage is replicated on a remote site using DRBD. In case of a failure of the primary site the decision is taken to move operations on the remote site. When the production site is back online sometimes the administrator is too eager to… Read More »

Solving “HA LVM: Improper setup detected * initrd image needs to be newer than lvm.conf”

By | April 24, 2017

In a Linux HA cluster setup on RHEL 6 that involves replication between sites using DRBD suddenly after reboot of one of the nodes it was imposible to start any cluster service from that node. Surprinsingly there was no issue to do so from the other node. While looking in the /var/log/messages on the affected… Read More »

#Docker: Network monitoring with Docker-compose #LibreNMS environment stack

By | May 28, 2017

I started from a great post Monitoring your Ubiquiti home-network with a Docker LibreNMS and SNMP, to make my own network monitor where to gather all the network devices SNMP messages. Because I like docker compose files to start up all my components and I want to use a separate docker mysql I made the… Read More »

#Docker: Custom #JBoss EAP docker image with CLI applied patches and CLI configurations

By | May 28, 2017

In the following I am trying to create a Jboss EAP docker image with up-to-date patches and configurations applied using JBoss CLI. With this template I can then very easy setup any complex JBoss based application environment with ready defined data sources, connectors , resource adapters etc. In the following I will describe the steps… Read More »

#Docker: Production #Jboss client image that checks if the #Oracle container is initialized with data

By | April 7, 2017

Everybody that works with big vendor databases like Oracle or DB2 knows that when you have a lot of data and the database is initializing or recovering after a disaster there are dead times when the database isin a state of limbo. It is started but still not in usable state. Usually the enterprise applications… Read More »

Quick fix for selinux issues caused by un-tagged files

By | April 5, 2017

Sometimes weird things happen when selinux is activated and files are un-tagged or policies are missing. Because I do not want to apply the usual stupid Internet advice: “disable selinux” I am trying to fix it if possible. Two simple steps to alleviate some of the “issues” caused by selinux. STEP 1: Generate SELinux policy… Read More »

Letsencrypt Secured Private Registry for #Docker Swarm

By | August 29, 2017

This tutorial is part of the effort to deploy a complex business application on a docker swarm and is focused on deploying a swarm accessible secured private registry using letsencrypt certificates. The first step is to create the swarm, see Create and manage a Docker Swarm with Docker CE and register it to Docker Cloud… Read More »