So, I’m a slow learner. Tectonically slow. Sometimes it helps to keep track of the things I pick up over the course of a week to remind myself that I’m still breathing and haven’t (just) been sitting on my ass.

1/5

Things I Learned

  • Use git config --global push.default current to avoid having to specify branch on each push (wow, can’t believe I’ve been copying git branch output this whole time…)
  • Use Prefix+{ to swap pane positions in tmux
  • Istio integration framework’s metallb installation uses layer 2 (ARP) mode to assign LoadBalancer IPs from the back of kind’s subnet
  • You can use the --kubeconfig flag to specify a kubeconfig file to use for a kubectl command
  • Golang uses build tags to figure out which files to include in a given package. Looks like // +build .... Can also use file suffixes like platform_specific_code_linux.go to accomplish this

Things I Learned I Need to Learn More About

  • Don’t understand how the revision field in the IstioOperator correlates to the revision field in Helm values
  • Don’t understand why Envoy sets up listeners on targetPort for Gateways

1/6

Things I Learned

  • Istio sets up inbound listeners on targetPort since when the request reaches the proxy it will have already been translated by k8s networking layer! Makes sense, was thinking from outbound perspective where the listener should be on the port
  • ValidationWebhook broken for Istio revisions in general because the chart exists in base and points to /validate on an istiod instance

Things I Learned I Need to Learn More About

  • When a port 80 Gateway is created on an ingress-gateway with service mapping 80->8080, the listener will be configured to listen on port 8080. Where does this translation happen in the listener generation code?
  • More about KNative! Don’t know the first thing about it

1/7

Things I Learned

  • You can use replace istio.io/api => /path/to/local/api/work with go modules to replace dependencies with local versions (handy for istio/api experimentation, but cannot build in container without extra work)
  • Lots of things about how Istio translates from IstioOperator spec to Helm values (some things I wish I didn’t know…)
  • istioctl install --revision ... is an alias for istioctl install --set revision=...
  • You can set parallelism on Kubernetes jobs to determine how many pods to run at any given time

Things I Learned I Need to Learn More About

  • The differences between the istio-remote and istio-control charts in the Istio manifests
  • How does a request that reaches a Gateway with X-Forwarded-Proto get treated by Envoy?
  • What is the difference between the protocol field and the appProtocol field on a service port?