“A chain is no stronger than its weakest link” Any improvement made anywhere besides the bottleneck is an illusion. Any improvement made after the bottleneck is useless because it will always remain starved waiting for work from the bottleneck. Any improvement made before the bottleneck merely results in more ‘work’ piling up at the bottleneck. Identify the system’s constraint(s) (that which prevents the organisation from obtaining more of the goal in a unit of time) Decide how to exploit the system’s constraint(s) (how to get the most out of the constraint) Subordinate everything else to the above decision (align the whole system or organization to support the decision made above) Elevate the system’s constraint(s) (make other major changes needed to increase the constraint’s capacity) Warning!

Here are my top album pics for 2017 (in no particular order) Note: This is by no means an exhaustive list, it’s just the top albums that really stood out to me and in all fairness, I’ve thought of several others since so there may be a follow up post (or two). Father John Misty - Pure Comedy As a bonus, a short film was released with the album, available here. From Wikipedia: Most of Pure Comedy was written in 2015. It touches on themes of progress, technology, fame, the environment, politics, aging, social media, human nature, human connection and his own role in it all.

My good friend Joel Shea received a most unlikely gift this Christmas - A vintage HP 4951 Protocol Analyser. According to the HP Computer Museum: Original Price: $3595 The 4951B was replaced by the 4951C and 4952A in 1986. Both new models handled Async, BSC, SDLC, HDLC, X.25 and SNA protocols. The 4951C also handled DDCMP, while the 4952A did not. The 4952A handled X.21 while the 4951C did not. Both new analysers used a floppy dive (618 KB) for removable media. Promo Photo: Joel’s specimen: And the original spec sheet:

Using GlusterFS to provide volume storage to Kubernetes as a replacement for our existing file and static content hosting. This talk was given at Infracoders on Tuesday 14th November 2017. NOTE: Below link to slides currently broken - will fix soon! (03/08/2019) Click below to view slides (PDF version): Direct download link

In vim, you can add a comment at the top of files to set the syntax, e.g.: # vim: syntax=ruby In SublimeText there are many ways to detect syntax, one interesting approach I’ve recently found useful is to match on the top line in the file. For example, with Puppet there is a file called Puppetfile, it has no extension but it’s really Ruby syntax, so it’s useful to add linting incase you miss something simple like a , and break deployments. I use a plugin called ApplySyntax making it easy to apply syntax options to files, I believe you can do this in the languages syntax without the plugin but YMMV:

Earlier this week we started the process to upgrade one of our hypervisor compute clusters when we encountered a rather painful bug with HP’s Broadcom NIC chipsets. We were part way through a routine rolling pool upgrade of our hypervisor (XenServer) cluster when we observed unexpected and intermittent loss of connectivity between several VMs, then entire XenServer hosts. The problems appeared to impact hosts that hadn’t yet upgraded to XenServer 7.2. We now attribute this to a symptom of extreme packet loss between the hosts in the pool and thanks to buggy firmware from Broadcom and HP. We were aware of the recently published issues with Broadcom/HP NICs used in VMware clusters where NICs would be bricked by a firmware upgrade.

We’re in the process of shifting from using our custom ‘glue’ for orchestrating Docker deployments to Kubernetes, When we first deployed Docker to replace LXC and our legacy Puppet-heavy application configuration and deployment systems there really wasn’t any existing tool to manage this, thus we rolled our own, mainly a few Ruby scripts combined with a Puppet / Hiera / Mcollective driven workflow. The main objective is to replace our legacy NFS file servers used to host uploads / attachments and static files for our web applications, while NFS(v4) performance is adequate, it is a clear single point of failure and of course, there are the age old stale mount problems should network interruptions occur.

Of all the tools for reading news and subscribing to software releases, I still find RSS the most useful. I use Feedly to manage my rss subscriptions and keep all my devices in sync, but instead of using the Feedly’s own client, I use an app called Reeder as the client / reader itself. Link: My Feedly RSS Feed FeedlyRSS feed subscription management Features: Keyword alerts. Browser plugins to subscribe to (current) url. Notation and highlighting support (a bit like Evernote). Search and filtering across large numbers of feeds / content. IFTTT, Zapier, Buffer and Hootsuite integration. Built in save / share functionality (that I only use when I’m on the website).

I wanted to try Android for a couple of weeks, I like staying on top of technology, gadgets and making sure I never become a blind ‘zealot’ for any platform or brand. The OnePlus 3I did a lot of research and decided to try the “Oneplus 3” as it was good bang-for-buck, ran the latest software had plenty of grunt with the latest 8 core, high clock speed Qualcomm processor coupled with 6GB of DDR4 - the specs really are very impressive, especially for a $400USD phone. Hardware wise the unit is lovely, not as high build quality as my iPhone 6s+ but not nearly as bad as the Samsung Galaxy S3 or other Samsung devices I had tried in the past.