Makoto Saito mlsaito

kubectl multi-version brews

We need to run multiple versions of kubectl for compatibility with various clusters.

It's a bit easier to get and use multiple versions of kubectl using Homebrew than it is using Macports.

With brew, it's simple to:

Install a bunch of versions of kubectl (in the kubernetes-cli Formula)
Switch between them as needed

PSQL

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h or --help depending on your psql version):

-E: will describe the underlaying queries of the \ commands (cool for learning!)
-l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

Fix Previous Commits

$ git commit --fixup=8a465186
$ git rebase -i --autosquash 8a465186~1

Cherry Picking

Create a tunnel on your local:

$ ssh -f -N -L6379:<your redis node endpoint>:6379 <your EC2 node that you use to connect to redis> -i "key.pem"

Connect to redis exposed on your local:

$ redis-cli -h 127.0.0.1 -p 6379

Get a list of currently running Pod names:

$ kubectl get pods -o go-template --template '{{range .items}}{{.metadata.name}}{{"\n"}}{{end}}'

SSH directly into a pod:

$ kubectl exec --namespace  -it  -- bash

Implementation

Some vendors require you to call their API via TLS 1.2 and I don't see that much documentation on how to do this.

2 ways to make an HTTP request using HTTParty:

Directly calling Class method.

# Notice the `ssl_version` option, to specify ssl version of the HTTP request
response = HTTParty.get('http://api.stackexchange.com/2.2/questions?site=stackoverflow', ssl_version: :TLSv1_2)

cURL with Basic Authorization:

$ cURL -X POST -H "Authorization: Basic YWxhZGRpbjpvcGVuc2VzYW1l" https://localhost:3000

cURL with username and password (pretty much same with Basic Auth):

$ curl -X POST -H "Content-Type: application/json" \
 --user "usernameorclient_id:passwordorclient_secret" \

Find processes listening on a port:

$ lsof -i :3000

Kill process:

$ kill -9

Remove any stopped containers and all unused images (not just dangling images):

$ docker system prune -a

Stop all docker processes:

$ docker stop $(docker ps -a -q)

	#!/usr/bin/env bash

	#! This will output info to `users_info.csv`
	echo "Getting info from Redis. . ."

	redis-cli ping

	for i in {1..29885}; do
	#! as of 2018, we can use this: EMAIL=$(command) instead
	#! Reference: https://stackoverflow.com/questions/4651437/how-to-set-a-variable-to-the-output-of-a-command-in-bash