Archive for the ‘Operating Systems’ Category

Bare bones bleeding edge cluster

Tomcat(xN)+Kubernetes+Docker+Rocky

Audience: SysAdmin, DevOps, Un*x coders

Sometimes, just for exercise, I go nuts. This time I figured my exercise would be to create a Hello World micro-services demo by building a bare bones cluster on the bleeding edge Rocky 8.4 operating system. I say “bleeding edge” but in fact I would just be using recent stable versions of several technologies, rather than the actual bleeding edges.

You can read about my chosen technologies elsewhere, along with all manner of explanations, charts, diagrams and occasionally some sample configurations or lines of code. For this document I stick to command lines and raw configurations, with the aim of providing something that you can copy/paste verbatim and achieve the same result. If you [click title to read more…]

Front doors

We’ve all heard of “back door” access. This refers to a situation where some kind of access to the system is available that does not go through the normal procedures, and is sometimes present during the early stages of development to provide convenient and efficient ways to interact with a partially complete system.

Obviously, it is essential that the final version of the solution is built without these back doors present, otherwise you have a major hole in your security.

Then there is the front door, and that will be present in the final version you put into the hands of your customers.

During development it is tempting to make the front door as “convenient” as the back door, just [click title to read more…]

Long, long, long paths

You may not be familiar with the MAX_PATH limitation in Windows, but if you are then you know how much of a nuisance it can be. Windows, unlike Unix, limits the full path of a file to 260 characters. People of a certain vintage who remember the 8.3 file name format will laugh at 260 characters being called a limitation but to Unix followers the notion of such a limit is crazy.

That 260 character limit is there, has been for a very long time, and is even present in the current incarnation: Windows 10.

Why is this a problem? Normally it is not and one can work away for years and not even be aware of it, but as [click title to read more…]

All mapped out

I think it is pretty clear to everyone that location is a key concept in mobile data services today, whether you are using native apps or Web-based services. So it came as a bit of a surprise that Apple released their home-grown iOS 6 map application to replace the one based on Google’s map data. Google has spent about 7 years collecting map data, including satellite images, street images, locations of significant structures/businesses, public transport routes and timetables and much more. This made Google’s solution an excellent component in location-based services. There were a few map-related omissions in Google’s offering for the iPhone/iPad platforms, such as being unable to get a rotatable 3D perspective, or to have turn-by-turn directions spoken [click title to read more…]

CentOS 6 in VMWare 4

Here’s a quick summary of installing CentoOS 6 into VMWare Player 4. This summary isn’t for beginners, so I’m not going to mention the “obvious”…

First, my environment: I’m running Windows 7 as the host on an Intel dual-core machine with 8Gb RAM, on which I’ve installed the free VMWare Player version 4, and I have downloaded the DVD ISOs of the latest CentOS 6 distribution. Player 4 will happily run VM images created for Player 3, so if you are still on 3 then now is the time to upgrade.

Run Player and at the main window you get the option to run existing VMs or create a new one. Create a new VM with at least 2 Gb [click title to read more…]