Free SSL for machines in your private network

If you are running servers in your private network that need SSL, you can use LetsEncrypt and Certbot to automatically obtain and renew certificates for free. Even if your machines are not accessible from the internet. What you need: A static IP in your internal network for the server, like 192.168.1.2 Own a domain like […]

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A real world example of digital signature checking

In this post we will see exactly how we can check if a SSL certificate hasn’t been tampered with. We will use https://google.com as an example and we’re manually going to check that the certificate’s digital signature is valid. Other important steps such as traversing the entire chain is beyond the scope of this simple […]

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Zalenium a stable and scalable Selenium grid

I just want to give well deserved thumbs up to Zalando’s Zalenium Their own description says it best: Allows anyone to have a disposable, flexible, container based Selenium Grid infrastructure featuring video recording, live preview, basic auth & online/offline dashboards Getting up and-running really is only one docker pull and docker run command away.

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Containerising the development environment

One of the nice things about docker is that we can use all kinds of software without cluttering up our local machine. I really like the ability to have the development environment running in a container. Here is an example where we: Get a Node.js development environment with all required tools and packages Allow remote […]

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Docker on Raspbian: cgroup not supported on this system

Are you running Docker on Raspbian and getting the error: cgroups: memory cgroup not supported on this system Best solution is to add cgroup_memory=1 in /boot/cmdline.txt and reboot. PLease note, for future releases of Raspbian you will need the following instead: Alternatively, you can downgrade to an earlier docker version:

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Returning a collection of objects from a PowerShell function

If you’re writing a function that returns a collection then don’t forget to include the comma operator in the return statement. If you forget it your function will work correctly when the collection contains multiple objects, but fails when it contains 1 object. Take the following buggy example: If you execute this code when $myarray […]

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