juniorz

Software development hard truths

• Continuous Integration is a software development discipline, not your orchestrator tool.
• Branch-by-abstraction and trunk-based development is the right superior answer for adopting CI (https://twitter.com/jezhumble/status/1220036153488756736)
• Feature branches and PR features goes against the grain with adopting CI.
• Pair programming is hard and works (https://martinfowler.com/articles/on-pair-programming.html).
• "Success creates its own truth" (https://longreads.com/2020/08/20/how-to-learn-everything-the-masterclass-diaries/). Be wary of the gospel preached on a famous/pupular/successful person/company's blog post. Can their life lessons be applied to your (or someone else's) reality?

juniorz

• Dead Space development struggling to integrate changes from multiple teams/experts: https://youtu.be/BQ3iqq49Ew8?t=655
• Desktop apps: once in a while you kill a process eating all you RAM. Web apps: once in a while you kill the Google Chrome GPU task eating all your RAM after you open a GIF.
• Today's browser wars: migrating a customer's 100s open tab from Chrome to Firefox/Edge/Opera/Safari.
• Why it is important to make experimention cheap.
  • If it is hard to experiment (time and space) and it requires coordination and help, people willl be reluctant to throw bad experiments away.
  • https://youtu.be/WFu1utKAZ18?t=916
  • https://youtu.be/WFu1utKAZ18?t=1778
• The origin of Control Plane vs Data Plane and how the concept influenced UNIX design

juniorz

Keep-Alive

time telnet www-org.example.com 80

GET / HTTP/1.1
Host: www-org.example.com
Connection: keep-alive

(wait)

juniorz

package xmpp

import (
	"errors"
	"fmt"
	"log"
	"net"
	"net/url"

	"github.com/miekg/dns"

juniorz

kubectl logs has quirks due to log-rotation

kubectl logs does not take into account container log rotation (kubelet config containerLogMaxSize and containerLogMaxFiles). You can still find the latest rotated logs in /var/log/pods/<namespace>_<pod-name>_<pod-uid>/ though.

Don’t assume --since=0s will have all logs since the container started because it won't look into previous log files. Don't assume a long-running --follow will always give you latest logs, because it will not switch over to the new log after current is rotated.

See: kubernetes/kubernetes#59902

KUBECONFIG is not portable

juniorz

# Some good references are:
# http://russbrooks.com/2010/11/25/install-postgresql-9-on-os-x
# http://www.paolocorti.net/2008/01/30/installing-postgis-on-ubuntu/
# http://postgis.refractions.net/documentation/manual-1.5/ch02.html#id2630392

#1. Install PostgreSQL postgis and postgres

brew install postgis
initdb /usr/local/var/postgres
pg_ctl -D /usr/local/var/postgres -l /usr/local/var/postgres/server.log start

juniorz

How to build tor for WD My Cloud EX2

WD My Cloud EX2 has an Marvell Armada-370 CPU (Marvell PJ4Bv7 Processor rev 1 (v7l)) with 512MB RAM.

This device uses 32-bit binaries with 64K page size. WD releases a cross-compilation environment as part of its "WD My Cloud EX2 GPL Source Code". Download it from WD support page (making sure it matches your firmware version) and follow the instructions in My_Cloud_EX2_Release_Notes_GPL_*.txt to setup the environment. I recommend using a Debian OS.

The following packages are required to use the cross-compilation environment: build-essential automake lib32z1

Building dependencies

juniorz

(not always bizarre, sometimes just backfiring daily design)

Kubernetes

• HorizontalPodAutoscaler takes into account Terminating pods when calculating the metrics. The consequence is if a pod has a bug on its termination procedure, terminating pods as part of a scale down triggers a scale up.
  • It once did the same for Pending pods.
• Can't omit clusterIP if you ever set it (even if to "") https://gitlab.com/gitlab-org/charts/gitlab/issues/1710#note_262760589
• How do you force HTTPS redirection on Ambassador: you use a nginx sidecar
• How do you force static HTTP responses (401, for example) on Ambassador: you use a nginx sidecar

juniorz

Tecnology and Society

• http://appropriatingtechnology.org/?q=node/296

Kubernetes autoscaling

• kubernetes/kubernetes#1629
• https://github.com/kubernetes/community/blob/master/contributors/design-proposals/autoscaling/horizontal-pod-autoscaler.md
• https://github.com/kubernetes/community/blob/master/contributors/design-proposals/autoscaling/vertical-pod-autoscaler.md
• Scale to/from zero

juniorz

"Those that know, do. Those that understand, teach."

Aristoteles (supposedly)

Learning goals

• Establish a taxonomy for this segment of software development industry (the domain).
• Define evaluation criteria for products in the solution space.
• Assess the landscape of the solution space and how they fit the market.
• Better understand the problem space.