Harry Dam naviat

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)

What to Expect and Tips

• 45-minute systems interview, focus on responding to real world problems with an unhealthy service, such as a web server or database. The interview will start off at a high level troubleshooting a likely scenario, dig deeper to find the cause and some possible solutions for it. The goal is to probe your knowledge of systems at scale and under load, so keep in mind the challenges of the Facebook environment.
• Focus on things such as tooling, memory management and unix process lifecycle.

Systems

More specifically, linux troubleshooting and debugging. Understanding things like memory, io, cpu, shell, memory etc. would be pretty helpful. Knowing how to actually write a unix shell would also be a good idea. What tools might you use to debug something? On another note, this interview will likely push your boundaries of what you know (and how to implement it).

Design/Architecture

Interview is all about taking an ambiguous question of how you might build a system and letting

	#!/usr/bin/env python
	import argparse
	import redis


	def connect_redis(conn_dict):
	conn = redis.StrictRedis(host=conn_dict['host'],
	port=conn_dict['port'],
	db=conn_dict['db'])
	return conn

	/*
	Migrate documents from one elasticsearch endpoint to another.

	To squeeze out extra performance, disable index refresh and replicas on the target cluster:

	curl -XPUT 'http://elasticsearch:9200/_settings' -d '{
	"index" : {
	"refresh_interval" : "-1",
	"number_of_replicas": "0"
	}

	# Quick script to configure routes for a VPC peering connection
	# Searches a region for all peering connection and prompts to choose one
	# Configures routes between the peered networks for all routing tables
	# STS/AssumeRole not implemented cross-account peering. Instead,
	# Choose accepter/requestor depending on which credentials are set in the environment
	# Enter either IPv4 and IPv6 route destinations
	# Example usage:
	# ( Assuming boto credentials are configured)
	# $ pip install boto3
	# $ python3.6 peer_routes.py

	# eks.yml
	on:
	pull_request:
	push:
	branches: # array of glob patterns matching against refs/heads. Optional; defaults to all
	- master # triggers on pushes that contain changes in master

	name: Build and Deploy to EKS

	env:

	{
	"Version": "2012-10-17",
	"Statement": [
	{
	"Effect": "Allow",
	"Action": [
	"iam:CreateInstanceProfile",
	"iam:DeleteInstanceProfile",
	"iam:GetRole",
	"iam:GetInstanceProfile",

	cheat sheets.
	$ command line ruby cheat sheets
	PostgreSQL
	----------

	Create the filesystem
	----

	$ export PGROOT="/var/lib/postgres"
	$ mkdir -p $PGROOT/data && chown postgres.postgres $PGROOT/data

	#!/bin/bash -xe

	## SET BASIC VARIABLES
	EKS_CLUSTER="dev-cluster"
	IAM_ROLE_NAME=eksctl-$EKS_CLUSTER-iamserviceaccount-role
	EXTERNAL_SECRETS_POLICY="kube-external-secrets"

	#### CREATE POLICY TO ACCESS SSM/Secrets Manager
	cat << EOF > policy.json
	{