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In this post, I wanted to share some knowledge that I have gained recently. Sometimes your Puppet server might start returning 500 HTTP status codes. You should check puppetserver’s logs first of all, of course, but another thing to check is the puppetdb. puppetdb is the component which is responsible for storing Puppet-related data. In this case, there were memory-related problems on the puppetdb instance. The puppetdb logs in this case have looked like this: ...

In the Cloud-based computing world, a relatively popular free and open-source software product called Prometheus exists which lets you monitor and observe other things. One of the components of its user interface lets you execute ad-hoc queries on the data that it has and see their results - not just in a table but also in a graphical way as well. For example, this is a query time() which plots the current time using two dimensions: ...

Recently I had to do some capacity planning of this software that is relatively popular and it stands for the L in the ELK (Elasticsearch, Logstash, Kibana) stack so I thought that I should share what I have learned. While researching, I have found an appalling lack of information regarding this matter so I hope that this article will at least a bit help fill this void on the Internet. ...

Image result for puppet I have been using Puppet off-and-on by now for almost a couple of years and saw it transform from a domain-specific language with lots warts to a pretty and functional language. However, not all is completely fine and dandy. I feel that in some ways it could still be improved a lot. Namespaces support of modules in environments Puppet has somewhat good support for namespaces in the code with the special delimiter of :: which has a magical meaning for it: the Puppet agent expects to find the code in one level deeper when it sees such thing in a class name or a define. From now on, I will only talk about class objects and not other things which work similarly from the point of view of the parser. However, at the top level, all names of the class definitions (before ::, if it exists) are at the same, top-most scope. In a very big environment, you could easily run into such a situation that two different modules (competing implementation) configure the same piece of software and they have identical names. ...

Recently I have read a quite popular book called “The Design of Everyday Things”. I feel that with software slowly taking over more and more parts of the world, we could say that it also became an everyday thing and that we should design it like that. This blog post will be about it. There are certain, general design principles that were explained in that book which we should apply to the process of programming in general. ...

A simple house a.k.a. property Testing software is ubiquitous and people naturally expect it to be a part of any kind of software development process. There are many different kinds of forms it can take: at the most rudimentary level: ad-hoc testing; integration testing; synthetic testing; and many others One of the forms that are quite novel is property-based testing. Essentially, the idea is to check if the software that you’ve produced espouses certain characteristics under inputs which have certain distinctive qualities. It sounds very similar to ordinary unit tests however here the catch is that a random number generator is leveraged in this case. Or, you can think of fuzzing but for ordinary code, not binary interfaces. It lets you run a bunch of tests very quickly and find the edge cases under which your code might not work as expected. ...

Thanos 0.5.0-rc.0 has been recently released and the final 0.5.0 version is just around the corner. It is a good opportunity to look back on what has changed since the last version. I hope that I will be able to present a good enough perspective since I have been recently appointed as a maintainer of the project. Thanks to everyone who has contributed pull requests and bug reports 💖This could not have been done without you. ...

Intro There are two different schools of thought when thinking about how metrics are ingested into a monitoring system: either the metrics get pushed (usually via UDP) into the system or they get pulled (usually via HTTP). I might not mention that I have that in mind when saying “push or pull based systems” in some places to keep the article terse. The push method is used in systems such as Graphite whereas the pull method is used by monitoring systems like Prometheus. ...

Just like most pieces of software nowadays, Thanos is not an exception and there is some caching going on there. In particular, we will talk about the index cache and its’ size in Thanos Store. After a certain bug was fixed, a lot of problems came up to users who were running with the default size of 200MiB. This is because this limit started being enforced whereas it was not before. I feel that it would be the perfect opportunity to explain how it works and how to determine what would be the appropriate size in your deployment. ...

Like almost everyone, I also dream about starting my own business so that I could be free from the shackles of someone else and I would be my own boss. Or it could become potentially a source of passive income. As such, I have started reading some literature and sites like Indiehackers to learn about how others start their own software businesses. After all, software is the thing that I am most skilled in and so I ought to connect that with the other things which are involved in having a successful business to start my own software company. ...