In this post, we’ll walk through the process of getting virtual machines on two different hosts to communicate over an overlay network created using the support for VXLAN in Open vSwitch (or OVS). The test environment For this post, I’ll be working with two systems: node0.ovs.virt at address 192.168.122.107 node1.ovs.virt at address 192.168.122.174 These hosts are running CentOS 8, although once we get past the package installs the instructions will be similar for other distributions.
Kustomize is a tool for assembling Kubernetes manifests from a collection of files. We’re making extensive use of Kustomize in the operate-first project. In order to keep secrets stored in our configuration repositories, we’re using the KSOPS plugin, which enables Kustomize to use sops to encrypt/files using GPG. In this post, I’d like to walk through the steps necessary to get everything up and running. Set up GPG We encrypt files using GPG, so the first step is making sure that you have a GPG keypair and that your public key is published where other people can find it.
I sometimes find myself writing articles or documentation about git, so I put together a couple of terrible hacks for generating reproducible histories and pretty graphs of those histories. git synth The git synth command reads a YAML description of a repository and executes the necessary commands to reproduce that history. It allows you set the name and email address of the author and committer as well as static date, so you every time you generate the repository you can identical commit ids.
This is just a note that I’ve substantially changed how the post sources are organized. I’ve tried to ensure that I preserve all the existing links, but if you spot something missing please feel free to leave a comment on this post.
While working on a pull request I will make liberal use of git rebase to clean up a series of commits: squashing typos, re-ordering changes for logical clarity, and so forth. But there are some times when all I want to do is change a commit message somewhere down the stack, and I was wondering if I had any options for doing that without reaching for git rebase. It turns out the answer is “yes”, as long as you have a linear history.
OpenShift Container Storage (OCS) from Red Hat deploys Ceph in your OpenShift cluster (or allows you to integrate with an external Ceph cluster). In addition to the file- and block- based volume services provided by Ceph, OCS includes two S3-api compatible object storage implementations. The first option is the Ceph Object Gateway (radosgw), Ceph’s native object storage interface. The second option called the “Multicloud Object Gateway”, which is in fact a piece of software named Noobaa, a storage abstraction layer that was acquired by Red Hat in 2018.
Performance of the primary PyPi service has been so bad lately that it’s become very disruptive. Tasks that used to take a few seconds will now churn along for 15-20 minutes or longer before completing, which is incredibly frustrating. I first went looking to see if there was a PyPi mirror infrastructure, like we see with CPAN for Perl or CTAN for Tex (and similarly for most Linux distributions). There is apparently no such beast,
The SYM-1 is a 6502-based single-board computer produced by Synertek Systems Corp in the mid 1970’s. I’ve had one floating around in a box for many, many years, and after a recent foray into the world of 6502 assembly language programming I decided to pull it out, dust it off, and see if it still works. The board I have has a whopping 8KB of memory, and in addition to the standard SUPERMON monitor it has the expansion ROMs for the Synertek BASIC interpreter (yet another Microsoft BASIC) and RAE (the “Resident Assembler Editor”).
Let’s say you have a couple of sensors attached to an ESP8266 running MicroPython. You’d like to sample them at different frequencies (say, one every 60 seconds and one every five minutes), and you’d like to do it as efficiently as possible in terms of power consumption. What are your options? If we don’t care about power efficiency, the simplest solution is probably a loop like this: import machine lastrun_1 = 0 lastrun_2 = 0 while True: now = time.
I recently put together a short animation showing the spread of Covid throughout the Northeast United States: I thought it might be interesting to walk through the process I used to create the video. The steps described in this article aren’t exactly what I used (I was dealing with data in a PostGIS database, and in the interests of simplicity I wanted instructions that can be accomplished with just QGIS), but they end up in the same place.