One of my goals is lifelong learning. Since finishing school over a decade ago, most of my learning has taken place on the job or through reading technical books in the last decade. I often feel that books provide great surveys and details on theory (which are important!) but they’re light on useful information for practitioners. Coursera Coursera was the first experience I had with online classes. I’ve done three courses on Coursera: Computer Networks ( available here), Algorithms Part I, and Algorithms Part II....

Some days I feel that I’ve returned to my old DBA role, well… sort of. A lot of my day to day work revolves around a vast amount of data and applications for data storage and retrieval. I haven’t been a DBA by trade since 2011, nearly an eternity in the tech industry. To me, Designing Data-Intensive Applications was a wonderful survey of “What’s changed?” as well as “What’s still useful?...

Google Cloud Platform has the notion of resource labels which are often useful in tracking ownership and cost reporting. Google Cloud BigTable supports data exports as sequence files. The process uses Cloud Dataflow. Cloud Dataflow ends up spinning up Compute Engine VMs for this processing, up to –maxNumWorkers. I wanted to see what this was costing to run on a regular basis, but the VMs are ephemeral in nature and unlabelled....

I’ve been looking hard at datastores recently, in particular PostgreSQL + PostGIS. In school, I did a few GIS related things in class and I assumed it was magic. It turns out there is no magic. At work, we have an application that accepts polygons and returns objects whose location are within that polygon. In GIS-speak this is often called an Area of Interest or AOI and they’re often represented as a few data types: GeoJSON, Well-known Text and Well-known Binary (WKT/WKB)....

I had to fight a little with GPG Suite (Mac) and forwarding gpg-agent to a Ubuntu 16.04 target. This post describes what ended up working for me. Source Machine: macOS Sierra 10.12.6 GPG Suite 2017.1 (2002) Target Machine: gpg2 installed on Ubuntu 16.04 (sudo apt-get install gpg2 -y) Source machine: File: ~/.gnupg/gpg-agent.conf Add this lines: extra-socket /Users/[user]/.gnupg/S.gpg-agent.remote File: ~/.ssh/config Add these lines: RemoteForward /home/[user]/.gnupg/S.gpg-agent /Users/[user]/.gnupg/S.gpg-agent.remote ExitOnForwardFailure Yes Restart gpg-agent: gpgconf --kill gpg-agent gpgconf --launch gpg-agent Destination Machine: File: /etc/ssh/sshd_config Add this line:...

I found and upvoted this solution on ServerFault. TLDR: Use OS X Disk Utility to Create a New Sparse, Case Sensitive Disk Configure VirtualBox to use this new disk Some screenshots that may be helpful: From Disk Utility -> File -> New Image: From VirtualBox -> Preferences: 

While debugging an Ansible playbook, I tweeted about variable precedence: https://twitter.com/andyhky/status/734859666337861633 Through that tweet I learned how to spell mnemonic AND I got a recommendation to buy Mastering Ansible. This blog post is a quick review of Mastering Ansible. Overall, I enjoyed the book’s format more than anything else. The flow of objective/code/screenshot really made the concepts gel (using herp/derp in examples is a close second!). I’m an advanced Ansible user (over 3 years), and this book still showed me new parts of Ansible....

Rolling deployments is well covered in the Ansible Docs. This post is about using those rolling deployments patterns but with F5 Load Balancers. These techniques use the F5 modules require BIG-IP software version >= 11 and have been tested with Ansible 1.9.4. There are a couple of things to examine before doing one of these deployments: Preflight Checks Ansible’s pre_tasks / post_tasks Preflight Checks If you’re using a pair of F5s for High Availability, consider having a preflight check play to ensure your configurations are in sync and determine your primary F5:...

FlowBAT is a graphical flow based analysis tool. FlowBAT is a very snappy UI which wraps flow collection software called SiLK. My interests with FlowBAT and SiLK are around using Open vSwitch to push sFlow data to SiLK and FlowBAT to quickly query that data. Hopefully I’ll get around to posting about OVS, sFlow, SiLK and FlowBAT. While I was getting started with FlowBAT (and SiLK) I saw there weren’t any ansible roles for either component....

I’ve seen a couple of automated remediation tools get some coverage lately: FBAR Stack Storm And both have received interesting threads on Hacker News. One HN commenter that stood out (bigdubs): I don’t like being the voice of the purist in this, but this seems like a bandaid on a bullet wound. For most of the cases where this would seem to be useful there is probably a failure upstream of that usage that should really be fixed....