Weekly Snap: Introducing ZeroMQ, Alfresco Community, the OSMC Program & Flexible Downtime

12 – 16 September discussed document management systems, flexible downtimes, and introduced a distributed computing tool as well as the program to the upcoming OSMC.
Gunnar took a look at distributed computing using ZeroMQ. A C++ library with various messaging functions, ZeroMQ is usesful in scaling applications, by distributing it over multiple systems. One central component breaks down large tasks into smaller component tasks and transmits them to worker processes. It also compiles the results of the worker processes to form a whole again. In contrast to traditional multi-thread applications, no locks are needed as the individual worker processes have no common condition and they can be distributed across machines, making it scalable without bounds. Gunnar gave an example implementation and some tips to avoid common problems such as work units sizes and operating system independent message formats.
From our Managed Services team, Georg trialled document management systems and named Alfresco Community  as his top pick. Between Microsoft Sharepoint 2010’s easy installation yet cluttered feature and settings, and Agorum Core Pro’s complicated installation, Alfresco Community won hands down. With easy installation and a good range of features; Alfresco can also be linked to an Active Directory server for larger organisations.
Lennart then explained flexible downtimes. As opposed to fixed downtimes, the start of a flexible downtime begins at the point a host or service changes status. Taking a host in Icinga for example, the start time and end time can be chosen to have a minimum duration of 10 minutes. Within this time frame the host will be restarted, but taking into account the reboot duration, downtime could extend over the 10 minutes set.
Last but not least, Pamela announced the Open Source Monitoring Conference 2011 program. Two tracks of presentations over two days in English and German, should offer plenty for attendees to chat about. For those who want to pack in more, 3 intensive workshops on the conference eve are also on offer. But register quick, as Europe’s leading event on open source monitoring has been known to sell out.

Understanding flexible downtimes

Im Gegensatz zu festen Ausfallzeiten, ist die Anfangszeit des Ausfalls bei der Wahl einer flexiblen Ausfallzeit, nicht an einen festen Anfangszeitpunkt gebunden, sondern an dem Zeitpunkt an dem der Host oder Service seinen Status wechselt. Die Downtime endet dann an dem angegebenen absoluten Endezeitpunkt, aber mindestens erst nach der angegebenen Dauer. Ein Beispiel soll dies verdeutlichen.
Mit starttime und endtime wählt man ein Zeitfenster aus, in dem die Downtime starten soll, hier zwischen 13:44 und 15:44. Mit der duration wird hier festgelgt, das die Downtime mindestens 10 Minuten dauert. D.h. ist der Host in der angesetzen Zeitspanne ab einem Zeitpunkt nicht mehr erreichbar, dauert die Downtime mindestens bis 15:44.  Mindestens deshalb, weil wenn der Host erst um 15:42 neugestartet wird, die Downtime bis 15:52 dauert, also auch über den absolut angegebenen  Endzeitpunkt hinaus.

Lennart Betz
Lennart Betz
Senior Consultant

Der diplomierte Mathematiker arbeitet bei NETWAYS im Bereich Consulting und bereichert seine Kunden mit seinem Wissen zu Icinga, Nagios und anderen Open Source Administrationstools. Im Büro erleuchtet Lennart seine Kollegen mit fundierten geschichtlichen Vorträgen die seinesgleichen suchen.