The main theme for the session on the 8th of April of 2011 was operating systems.
Monitoring with Pandora FMS
The guest conference was by Sancho Lerena that presented Pandora FMS as an example solution for open source monitoring. He being in charge of a company that uses and develops the free software product was a bit too commercial talking about the advantages but we were able to go through the main concepts of system monitoring. Pandora FMS started developing at a moment where the initial developers saw that the available monitoring tools where lacking in flexibility, scalability and openness to the free software community (even the free software ones) so the decided to start from scratch. At beginning the whole package was free software but after the commercial success with Artica (main company giving support on Pandora FMS) some parts are closed source sadly.
Apart from the typical metrics you can do with software in a server there is also the possibility of doing environment monitoring with a device that senses metrics like humidity, temperature, etc. This can alert us on time before a catastrophe turns into a tragedy for our servers.
One of the most interesting things about Pandora FMS is the many systems supported by the agents (pieces of software in charge of reading metrics and sending theme to the appropiate server). You can even do inventories of your hardware by gathering all this data.
The slides are basically the info you can find on the website.
Free operating systems
The available free operating systems typically have a UNIX structure so the UNIX history is important and the derivatives that existed over time. This makes that some of them share many characteristics and code while others (mainly Linux) were complete rewrites based on ideas of other UNIX systems at that time. There is a standard between all them called POSIX that makes many applications and scripts easily portable between them.
There is a very interesting graphic figure on wikipedia about the evolution of the different versions.
Between the different UNIX that are descendants of the original source code we have the BSD family with the freeBSD as the most popular distribution that includes features like jails or a direct port of the advanced filesystem ZFS. Is worth also mentioning openBSD for being the home of the firewall package called pf. Is important to note that in the top 10 of less downtime system 9 of them are BSDs.
Another family would be the Solaris with distributions like openSolaris (abandoned after the acquisition of Sun by Oracle) or openIndiana that aims to be compatible with the Solaris distributed by Oracle. One of the main features it has is the ZFS filesystem and full virtualization framework that includes network virtualization.
An then we have the Linux systems with a huge adoption in the server landscape with big distros like RedHat, CentOS, Debian, Ubuntu,...
In Linux we also find many families that start to differ in things like the package manager system.
The main advantage of the Linux platform is very consolidated and is widely tested with huge quantity of packages available.
Of course is important to mention that there is cooperation and feedback between all this free systems that leads to an enriched free ecosystem that enjoys improvements from all sides.
As we pointed out there is strong features in each of the different systems and many fail to appreciate this diversity and dedicate their career centered in one operating system (usually Linux). With the growth that we see in virtualization we can start to envision more of a hybrid system that take the best of each world for each of the specific use cases.
Slides: operating systems
UPDATE: the workload from the course and the university kept me from writing more about this course so this is the last entry but there were many interesting topics covered like filesystems, virtualization, high availabilty, scripts and web servers.