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How to keep cluster connections cleanly separated

With time the .kube/config file will contain a mix of dev, test and prod cluster references. It is easy to forget switching off from a prod cluster context and make a mistake and run for example kubectl delete ns crossplane-system.

Direnv based setup

Use the following setup to avoid these kinds of errors and keep clusters separate.

Install direnv

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mysql-client in Kubernetes to test your connection to mysql server

kubectl run mysql-client --image=mysql:5.7 -it --rm --restart=Never -- /bin/bash

mysql -h mysql-service -uroot -proot_password -e 'SHOW databases;'

OR

mysql -h mysql-service -uroot -proot_password

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top (the UNIX process inspector) cheat sheet

This is a list of the most helpful keyboard commands I use within top.

The basics

h shows help on interactive commands. Also see the top manual page

q to quit the program.

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pipeline {
    agent any

    parameters {
        string(name: 'environment', defaultValue: 'default', description: 'Workspace/environment file to use for deployment')
        string(name: 'version', defaultValue: '', description: 'Version variable to pass to Terraform')
        booleanParam(name: 'autoApprove', defaultValue: false, description: 'Automatically run apply after generating plan?')
    }
    
    environment {

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package something

import (
	"bytes"
	"errors"
	"fmt"
	"io/ioutil"
	"net/url"
	"path"
	"sync"

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Filling an array or slice with a repeated pattern

Looking for an efficient pure GO approach to copy repeating patterns into a slice, for a toy project, I ran a few tests and discovered a neat approach to significantly improve performance. For the toy project, I am using this to fill a background buffer with a specific RGB color pattern, so improving this performance significantly improved my acheivable framerate.

All the test were run with a buffer of 73437 bytes, allocated as follows

var bigSlice = make([]byte, 73437, 73437)

Fill the slice with the value 65 by looping through each element and setting the value

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System Updates

http://bookofzeus.com/harden-ubuntu/initial-setup/system-updates/

Keeping the system updated is vital before starting anything on your system. This will prevent people to use known vulnerabilities to enter in your system.

sudo apt-get update
sudo apt-get upgrade
sudo apt-get autoremove
sudo apt-get autoclean

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package main

import (
	"fmt"
	"reflect"
)

type Foo struct {
	FirstName string `tag_name:"tag 1"`
	LastName  string `tag_name:"tag 2"`

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AWS Golang SDK examples

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Tools

• Kops https://github.com/kubernetes/kops/blob/master/docs/README.md
• Kubectl https://kubernetes.io/docs/tasks/tools/install-kubectl/
• kubespy https://blog.pulumi.com/kubespy-trace-a-real-time-view-into-the-heart-of-a-kubernetes-service
• kops https://icicimov.github.io/blog/virtualization/Kubernetes-Cluster-in-AWS-with-Kops/

Presentations