Video : Ansible Playbooks : Tags


In today’s video we demonstrate how to use handlers in Ansible Playbooks.

The video is based on the following article.

You might find some useful stuff here.

The star of today’s video is Tanel Poder, who thinks he’s at the bow of a Viking ship by the look of it. 🙂

Cheers

Tim…

Technology Evolution : What does “the best” even mean?

I was watching a Twitter thread develop, where people were discussing which of two pieces of technology were “the best”, and I found myself thinking of evolution and selection pressure. I’m going to speak in simple terms, so I apologise in advance to folks with an education in this stuff, who are irritated by my simplifications…

Selection Pressure

Organisms evolve because of selection pressure. There is something about their environment that makes certain changes advantageous. Take the case of the peppered moth. To cut a long story short, it was a pale moth. Being pale was good camouflage as the places it hung around were a similar colour, so predators found it hard to spot them. Any mutations that made a peppered moth darker, made it more likely to be spotted and eaten, so mutations that caused the darker moths were unlikely to get through to the next generation. If you get eaten, you are less likely to breed. So there was a selection pressure in favour of being a pale peppered moth. Then along came the industrial revolution, which covered trees and walls in soot. All of a sudden, being pale made it easy for predators to see you and reduced your chances of breeding. Any moths with a mutation causing a darker colour were at an advantage, were more likely to breed, and quickly the predominant colour of peppered moths in industrial regions changed. The selection pressure was now for darker peppered moths.

In contrast, alligators have remained relatively unchanged since before the extinction of the dinosaurs. Sizes vary, but they look pretty much the same. Why? They are already the perfect design for their lifestyle, so there is no selection pressure forcing a change. If some new mutation happens, but it doesn’t give an advantage that affects the alligators chances of breeding, it’s unlikely to spread through the population. The selection pressure is low for the new mutation.

So what’s this got to do with technology? I’m hoping that’s simple for you to see.

If you invent a really smart bit of technology, but it has no major advantages over the existing technology out there, it’s unlikely to obliterate its competitors. Even if there is a technical benefit, that benefit has to be sufficiently large to make people stand up and take notice.

When we look at the database market, relational databases are the alligators. They are really well suited for the role they play. Every time a new non-relational engine comes along, it’s easy to get excited and think of it as the RDBMS-killer, but they are typically targeting different problems. The biggest threat to a specific relational database at the moment is other relational databases…

Survival of the Fittest

When people read “survival of the fittest”, they often forget that “fittest” relates to ability to breed and pass on your genes. The male peacock has stupid tail feathers that slow it down and put it at a higher risk of predation, but the peahens are all about the crazy tail feathers, so the physical disadvantage of the crazy tail feathers is a breeding advantage. Effectively the “least fit” for survival becomes the “most fit” for breeding…

But what about the peacock’s tail feathers in technology? There are a number of factors that make a technology attractive apart from technical excellence, so it’s not always “the best” that wins. For example:

  • Brand : I guess this is the obvious one. Apple is a premium brand. People will often spend extra money for a technically worse product because of the attraction of a brand. There is a reason companies spend big money on advertising and promoting their brand.
  • Community Support : If a product has a vibrant community, where it’s easy to get answers and support, it will be more attractive than a product with bad support and a weak community. Why intentionally put yourself at a disadvantage?
  • Staffing : It doesn’t matter how good a product is, if you can’t get staff with those skills, it’s probably not a great idea to base your future on it. This can be a problem for new technologies, but it also goes for old technologies that are falling out of favour. I wouldn’t be starting a new project using COBOL, even if it were well suited to the task.
  • Cost : There is a reason Android phones have a bigger market share than iPhones. They are cheaper, and therefore more attainable. Cost should be judged on total cost of ownership (TCO), not just the headline price tag…

I know this post has rambled a lot, but coming back to my original point, when I hear someone arguing about technical merits of a product, I find myself wondering if that’s actually relevant at all. Maybe it’s only a small fraction of what really matters…

Cheers

Tim…

PS. The first picture is a crocodile, not an alligator. I know they are different, but I liked this picture… 🙂

Video : Ansible Playbooks : Files and Templates

In today’s video we demonstrate how to use handlers in Ansible Playbooks.

The video is based on the following article.

You might find some useful stuff here.

The star of today’s video is Dan Norris, who is looking to the heavens for inspiration. 🙂

Cheers

Tim…

Video : Ansible Playbooks : Handlers

In today’s video we demonstrate how to use handlers in Ansible Playbooks.

The video is based on the following article.

You might find some useful stuff here.

The star of today’s video is my dad, Graham Wood, who spend most of his time galivanting and spending my inheritance, which I’ve been waiting patiently for!

Cheers

Tim…

Video : Ansible Playbooks : Host and Group Variables

In today’s video we demonstrate how to use lists and loops in Ansible Playbooks.

The video is based on the following article.

You might find some useful stuff here.

The star of today’s video is Toon Koppelaars, famous for The Helsinki Declaration (IT Version), which you may know better these days as the SmartDB approach to building applications.

Cheers

Tim…

Operating Systems for Oracle Databases, Including Windows This Time… (Poll Results Discussed)

Last week I put out a post about operating systems used for running Oracle databases.

Operating Systems for Oracle Databases (Poll Results Discussed)

This was the first question from the previous post.

Which operating system are you using for your Oracle database servers?

Unfortunately I forgot to include Windows. A number of people contacted me about this, asking if I would ask the question again and include Windows this time, so I did. Also, this time I was explicit about production systems, because I suspect some people were answering about their home setup… 🙂

So here we go for the second time…

Which operating system are you using for the majority of your **production** Oracle Databases servers? Not demo kit on your PC at home. A repeat of last week, but remembering to include Windows this time…

We can see Linux is still the clear winner, with UNIX and Windows battling it out for the second place spot. Going back to my statement from the last post, there is no point in purposely making yourself a minority, which would clearly suggest Linux is the place to be. Windows is a slight exception to that, because if your company has no experience on Linux, but a good grounding in Windows administration, it might be a good idea for you to stick with Windows, rather than doing a bad job with Linux. I can’t imagine there are many places with good UNIX skills and no Linux skills, so I’m not going to give the same “get out of jail free card” for that. 🙂

So as I said before, Linux is dominating, so you can see why there is so few posts about Oracle on other platforms these days…

Cheers

Tim…

Video : Ansible Playbooks : Lists and Loops

In today’s video we demonstrate how to use lists and loops in Ansible Playbooks.

The video is based on the following article.

You might find some useful stuff here.

The star of today’s video is Øyvind Isene, who took a break during coffee time to let me film this clip.

Cheers

Tim…

Operating Systems for Oracle Databases (Poll Results Discussed)

I put out some questions on Twitter a couple of days ago, asking about the operating systems people were using for their Oracle database servers.

As with all these polls, we have to discuss some caveats. Most of the people that follow me are from the Oracle community, so that puts a heavy bias on the outcome. The questions relate to Oracle databases, which also influences the results. Someone may choose one distribution to run Oracle workloads, and a different distribution to run non-Oracle workloads. We also have to remember the sample size is small. Despite this, I’m going to discuss the results as if this were a representative sample of people, even though I accept it may not be. 🙂

This was the first question I asked.

Which operating system are you using for your Oracle Databases servers?

You’ll notice I totally forgot to include Windows, which was a shame because it would have been nice to see that. My main focus was to see how many people were still holding on to the traditional UNIX systems. There was a really strong showing for Linux over UNIX, which was hardly surprising. Every year the dominance of Linux is increasing. A few years back a lot of big companies were still using the traditional UNIX systems, but I guess a lot of people have got sick of spending that sort of cash, and some have probably switched to buying Exadata kit instead. I cant say I’m surprised by this result.

Something I’ve said repeatedly over the years is you should stick to the operating system that is the most popular, as that is the one that is going to get tested the most. There is no point in purposely making yourself a minority IMHO. Having lived through the death of Oracle on Tru64 and HP-UX, I wouldn’t dream of using anything other than Linux now.

This was the next question.

For Linux users, which Linux distro are you using for your Oracle database servers?

Over 65% of the folks picked Oracle Linux, and about 27% picked RHEL. The fact this is a poll about Oracle database servers no doubt added to the skew in this result. Oracle have done a good job of promoting Oracle Linux, and the fact it is free probably helps a lot. I thought Oracle Linux would be the winner here, but I’m not sure I expected it to be by this much. Personally I wouldn’t run on anything other than Oracle Linux by choice. Remember, this is what Exadata uses, and this is what Oracle Cloud uses.

I suspect some of the people that picked “Other” were speaking about non-production systems. Perhaps I should have made it clear I was thinking about production, not test labs…

This was the final question.

For Enterprise Linux users, which version of Oracle Linux and/or RHEL are you using for your Oracle database servers?

It’s good to see that nobody is owning up to OL5/RHEL5. There are still a few things lingering on OL6/RHEL6, but I guess those are probably running old versions of the database.

OL7/RHEL7 is still the most common version, but I guess a lot of this is down to the long lifespan of database servers. I suspect many of these servers were provisioned some time ago. I’m hoping most new deployments are using OL8/RHEL8.

So nothing really that surprising about the outcome of this batch of questions. Pity I didn’t include Windows in the first question. Maybe next time…

Cheers

Tim…

Video : Ansible Playbooks : Introduction

In today’s video we’ll introduce Ansible Playbooks.

There’s quite a lot to cover, so this is only one of several videos covering playbooks. The video is based on the following article.

You might find some useful stuff here.

The star of today’s video is Bailey, who has been known to associate with Connor McDonald at times…

Cheers

Tim…

Why Automation Matters : Taking a step backward to move forward!

There was a small thread on Twitter today about unit testing, which I’m going to extrapolate to automation generally.

There can be a certain reluctance towards writing unit tests. I guess the thinking goes, I’m here to write code and solve problems, not waste time writing test code. Unit test quality and code coverage varies, but it’s not unusual to hear people say their unit tests have more lines of code than the code they are testing. I guess that adds to the reluctance. What some people fail to see is once the unit tests are written, they may never have to manually test that code again. If the code changes over time, the unit test may only need a few small tweaks to bring them up to date. Over the lifetime of the project, that initial investment can represent a massive saving…

This is true of many aspects of automation. Yes, you can create a new database in a few minutes by clicking some buttons on a GUI, and that’s fine when you get one request a week. What happens when developers want a new database for every test they run? Your button presses don’t scale. If instead you automated the process, you would never have to manually create a database again, and developers could build and burn databases to their heart’s content.

You could be the gatekeeper who runs scripts in the production environment, but what happens when you’re on holiday? What happens when the rate of production deployments increase? You become the bottleneck doing meaningless work. If you had helped build a deployment pipeline, those production deployments could happen automatically, with the correct governance of course.

I’ve said it before in this series, but I’ll say it again. Working in the tech industry is like swimming upriver. You can’t just stop swimming, because that means you are moving backwards. If more water is added to the river, the flow rate increases and you are overwhelmed. You have to keep trying to improve your efficiency to protect yourself against what is coming round the next bend…

I know it can be hard when you have a pressing deadline, but you really are taking a step backward to move many steps forward!

Check out the rest of the series here.

Cheers

Tim…