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What do Etcd, Consul, and Zookeeper do?

• Service Registration:
  • Host, port number, and sometimes authentication credentials, protocols, versions numbers, and/or environment details.
• Service Discovery:
  • Ability for client application to query the central registry to learn of service location.
• Consistent and durable general-purpose K/V store across distributed system.
  • Some solutions support this better than others.
  • Based on Paxos or some derivative (i.e. Raft) algorithm to quickly converge to a consistent state.
• Centralized locking can be based on this K/V store.

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Go (Golang) Standard Library Interfaces (Selected)

This is not an exhaustive list of all interfaces in Go's standard library. I only list those I think are important. Interfaces defined in frequently used packages (like io, fmt) are included. Interfaces that have significant importance are also included.

All of the following information is based on go version go1.8.3 darwin/amd64.

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Using a Local Registry with Minikube

Install a local Registry

These instructions include running a local registry accessible from Kubernetes as well as from the host development machine at registry.dev.svc.cluster.local:5000.

1. Use the docker CLI to run the registry:2 container from Docker, listening on port 5000, and persisting images in the ~/.registry/storage directory.

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vpngate.py

This script allows to use the free VPN service provided by VPNGate in an easy way. The user just needs to provide the desidered output country, and the script automatically chooses the best server.

After this step, OpenVPN is launched with the proper configuration. The VPN can be terminated by pressing Ctrl+C.

Usage

Run the script by providing the desired output country:

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let regex;

/* matching a specific string */
regex = /hello/; // looks for the string between the forward slashes (case-sensitive)... matches "hello", "hello123", "123hello123", "123hello"; doesn't match for "hell0", "Hello" 
regex = /hello/i; // looks for the string between the forward slashes (case-insensitive)... matches "hello", "HelLo", "123HelLO"
regex = /hello/g; // looks for multiple occurrences of string between the forward slashes...

/* wildcards */
regex = /h.llo/; // the "." matches any one character other than a new line character... matches "hello", "hallo" but not "h\nllo"
regex = /h.*llo/; // the "*" matches any character(s) zero or more times... matches "hello", "heeeeeello", "hllo", "hwarwareallo"

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# https://github.com/rg3/youtube-dl/
# On ubuntu: apt-get install libav-tools

# Download Playlist to batch of MP3s
youtube-dl -f bestvideo+bestaudio --extract-audio --audio-format mp3 --prefer-avconv --playlist-random https://www.youtube.com/playlist?list=XXXXX

# Download individual song
youtube-dl -f bestvideo+bestaudio --extract-audio --audio-format mp3 --prefer-avconv https://www.youtube.com/watch?v=ZZZZZZZ

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#!/bin/bash

# As the "bufferbloat" folks have recently re-discovered and/or more widely
# publicized, congestion avoidance algorithms (such as those found in TCP) do
# a great job of allowing network endpoints to negotiate transfer rates that
# maximize a link's bandwidth usage without unduly penalizing any particular
# stream. This allows bulk transfer streams to use the maximum available
# bandwidth without affecting the latency of non-bulk (e.g. interactive)
# streams.

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#Open vSwitch Lab

Get started with Open vSwitch, flows and OpenFlow controllers.

##Pre-reqs

Linux system with OVS installed.

##Setup

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DB

ovs-vsctl list open_vswitch
ovs-vsctl list interface
ovs-vsctl --columns=ofport,name list Interface
ovs-vsctl --columns=ofport,name --format=table list Interface
ovs-vsctl --format=table --columns=name,mac_in_use find Interface name=br-dpdk1
ovs-vsctl get interface vhub656c3cb-23 name

ovs-vsctl set port vlan1729 tag=1729

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#!/usr/bin/python

from mininet.node import OVSController

from mininet.topo import SingleSwitchTopo
from mininet.net import Mininet
from mininet.log import lg
from mininet.cli import CLI