Category Archive: Raspberry Pi

Nov 30

JVM Choice Matters (a lot!)

I’m one of the lucky folk who was able to obtain a Raspberry Pi Zero for $5. Originally this was going to be an article reviewing the Pi Zero to see how much of a difference the overclocking really makes. That and my impressions of the Zero will be in a later post. TL;DR: The …

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Oct 07

Hypriot Does it Again

Many thanks and kudos to the most excellent people at Hypriot on their latest release! Hypriot has made Docker on the Pi easy — prior to their distribution it took a lot of blood, sweat, and tears to compile and get Docker working on the Pi. (Trust me!!! Been there, done that, have the t-shirt). …

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Oct 02

Multifarious v2

While at a DevOps Birds of a Feather session at Ohio Linux Fest today I was describing to John Willis (@botchagalupe) my experiments with Docker and the Pi Swarm. Along the way, I mentioned that I’d gotten heterogenous docker swarms working using Powerstrip — aka Multifarious, first described in Heterogenous Docker Swarms Teaser. In so …

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Sep 07

Bulk Adding Hosts to a Pi Swarm

I’ve refreshed my stack and am rebuilding the cluster. I’m using Hypriot for the linux distribution, but I’m a smart sysadmin (read lazy) and don’t want to manually add them each time. Also, I want to make a script so that I can quickly rebuild. This is inspired by Let Docker Swarm all over your …

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Sep 07

Viewing Raspberry Pi Config Variables and More

Sometimes it’s helpful to see if a particular parameter is set or not on the raspberry pi. This is where vcgencmd. However, vcgencmd is useful for many other things.

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Aug 27

Stronger Faster Algorithms

Oft times all thoughts of algorithms are left behind with school. If they’re not, it can be too easy to get caught up in spending too much time trying to do something the “most efficient” way at the expense of spending two weeks coding to save a few milliseconds, but still there is a lot …

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Apr 28

Heterogenous Docker Swarms Teaser

Note: This is all very experimental; Docker does not support any architecture other than X86_64. The last few evenings I’ve been working on Mulitifarious, a means of creating heterogenous Docker Swarms. I’d previously found that I can create a swarm with heterogenous members — a swarm which has, say, X86_64 and Raspberry Pi members. The …

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Apr 21

‘Piping’ Hot Docker Containers

One of the possibly lesser used flags for docker run is -a which allows you to attach the container’s STDIN, STDOUT or STDERR and pipe it back to the shell which invoked the container. This allows you to construct pipelines of commands, just as you can with UNIX processes. For instance, using UNIX commands to …

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Apr 19

Docker Containers: Smaller is not always better

Generally smaller Docker containers are preferred to larger ones. However, a smaller container is not always as performant as a larger one. By using a (slightly) larger container, performance improved over 30x. TL;DR The grep included in busybox is painfully slow. When doing using grep to process lots of data, add a (real) grep to …

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Apr 18

Naive Substructure Substance Matching on the Raspberry Pi

Chemists can search databases using parts of structures, parts of their IUPAC names as well as based on constraints on properties. Chemical databases are particularly different from other general purpose databases in their support for sub-structure search. This kind of search is achieved by looking for subgraph isomorphism (sometimes also called a monomorphism) and is …

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