jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

tsiege

ANNOUNCEMENT

I have moved this over to the Tech Interview Cheat Sheet Repo and has been expanded and even has code challenges you can run and practice against!






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ejlp12

ECS Best Practices

• Understand and check Service Quota of ECS/Fargate and other related services
• Cluster
  • Use IaC for setting up resources eg. CloudFormation, AWS CDK, Terraform
    • Use copilot for simple setup
    • CloudFormation reference architecture template
      • https://github.com/nathanpeck/ecs-cloudformation
      • https://github.com/awslabs/aws-cloudformation-templates/tree/master/aws/services/ECS
• CDK for ECS: blog

chsh

#
# A:
# pubsub = PgPubSub.new('channelname')
# pubsub.subscribe do |data|
#  puts "data: #{data} is coming!"
# end
#
# B:
# pubsub = PgPubSub.new('channelname')
# pubsub.publish("hello world")

Mithrandir0x

// Source: https://groups.google.com/forum/#!topic/angular/hVrkvaHGOfc
// jsFiddle: http://jsfiddle.net/pkozlowski_opensource/PxdSP/14/
// author: Pawel Kozlowski

var myApp = angular.module('myApp', []);

//service style, probably the simplest one
myApp.service('helloWorldFromService', function() {
    this.sayHello = function() {
        return "Hello, World!"

maxim

#!/usr/bin/env bash
#
# gh-dl-release! It works!
# 
# This script downloads an asset from latest or specific Github release of a
# private repo. Feel free to extract more of the variables into command line
# parameters.
#
# PREREQUISITES
#

tallclair

apiVersion: extensions/v1beta1
kind: PodSecurityPolicy
metadata:
  name: restricted
  annotations:
    seccomp.security.alpha.kubernetes.io/allowedProfileNames: 'docker/default'
    apparmor.security.beta.kubernetes.io/allowedProfileNames: 'runtime/default'
    seccomp.security.alpha.kubernetes.io/defaultProfileName:  'docker/default'
    apparmor.security.beta.kubernetes.io/defaultProfileName:  'runtime/default'
spec:

hvelarde

# get total requests by status code
awk '{print $9}' /var/log/nginx/access.log | sort | uniq -c | sort -rn

# get top requesters by IP
awk '{print $1}' /var/log/nginx/access.log | sort | uniq -c | sort -rn | head | awk -v OFS='\t' '{"host " $2 | getline ip; print $0, ip}'

# get top requesters by user agent
awk -F'"' '{print $6}' /var/log/nginx/access.log | sort | uniq -c | sort -rn | head

# get top requests by URL

Informatic

cloud-init is absolute cancer. Its code is horrible. It has no documentation at all.

It took me 5 fucking hours to figure out how to properly configure networking on recent cloud-init (Ubuntu 16.04 cloud image) with local datasource.

It's not mentioned anywhere you need to provide dsmode: local. (but only if you need network-config, besides that everything is fine; someone below noted that -m flag does the same thing, good to know) Of course nobody needs documentation for network-config format either. (cloudinit/net/__init__.py is a protip, enjoy the feces dive)

Oh, and by the way - no, it's not possible to provide network-config to uvt-kvm without patching shit.

lizthegrey

default['sshd']['sshd_config']['AuthenticationMethods'] = 'publickey,keyboard-interactive:pam'
default['sshd']['sshd_config']['ChallengeResponseAuthentication'] = 'yes'
default['sshd']['sshd_config']['PasswordAuthentication'] = 'no'