Posts

Why am I creating a new blog? What was wrong with the old blog? Why don’t I use Medium? The short version: The old blog is frozen in time, like a prince caught in amber 1 or a dandy in aspic 2. I can no longer post to it. The old blog, the Pivotal Engineering Journal, which many of Pivotal’s engineers contributed to, was archived a year after VMware acquired Pivotal. Every acquisition brings changes, and this was, in the scheme of things, a very minor one. At least VMware kept the blog instead of simply discarding it. ...

My co-worker Belinda Liu turned to me and said, “I don’t like these tests at all; they’re hard to follow, and I’m not sure what they’re testing.” I looked at the tests that I had spent much of yesterday afternoon working on. She was right: they were hard to follow (even for me, who had written some of them!). How had we gotten here? Our code was straightforward, but our tests were byzantine (excessively complicated). We identified two problems: ...

0. Abstract HAProxy is an optional load balancer included in the canonical open source Cloud Foundry deployment. Its intended use is on IaaSes (Infrastructures as a Service) that do not offer built-in load balancers [0]. On vSphere, this means without the optional network virtualization solutions, NSX-T and NSX-V. This blog post describes how to assign an IPv6 address to an HAProxy load balancer in a Cloud Foundry deployment. 1. Pre-requisites Users following this blog post should be familiar with BOSH, BOSH’s manifest operations files, IPv6, and deploying Cloud Foundry using cf-deployment. ...

Abstract “How much faster will my VM’s disks be if I upgrade my ZFS-based (Z File System) NAS to 10 GbE?” The disks will be faster, in some cases, much faster. Our experience is that sequential read throughput will be 1.4✕ faster, write throughput, 10✕ faster, and IOPS, 1.6✕ faster. We ran a three-hour benchmark on our NAS server before and after upgrading to 10 GbE. We ran the benchmark again after upgrading. The benchmark looped through write-read-iops tests continuously. ...

Abstract Smartphone authenticator apps such as Google Authenticator and Authy implement software tokens that are “two-step verification services using the Time-based One-time Password Algorithm (TOTP) and HMAC-based One-time Password algorithm (HOTP)” Smartphone TOTP, a form of Two-factor authentication (2FA), displays a 6-digit code derived from a shared secret, updating every thirty seconds. The shared secret is presented only once to the user, typically with a QR (Quick Response) Code which is scanned by the authenticator app. ...