marwei

Kafka 0.11.0.0 (Confluent 3.3.0) added support to manipulate offsets for a consumer group via cli kafka-consumer-groups command.

1. List the topics to which the group is subscribed

kafka-consumer-groups --bootstrap-server <kafkahost:port> --group <group_id> --describe

Note the values under "CURRENT-OFFSET" and "LOG-END-OFFSET". "CURRENT-OFFSET" is the offset where this consumer group is currently at in each of the partitions.

2. Reset the consumer offset for a topic (preview)

ruanbekker

My Elasticsearch cheatsheet with example usage via rest api (still a work-in-progress)

Shortlinks:

• Cluster Health
  • Index Level
  • Shard Level
• Nodes Overview
• Indices Overview
• Cluster Maintenance

JonCole

Some of the Redis best practices content has moved

This content from this markdown file has moved a new, happier home where it can serve more people. Please check it out : https://docs.microsoft.com/azure/azure-cache-for-redis/cache-best-practices.

NOTE: Client specific guidance listed below is still valid and should still be considered. I will update this document once all content has been moved.

leommoore

#MongoDB 3.2.x Replica Sets on AWS EC2 A MongoDB replica set provides a mechanism to allow for a reliable database services. The basic replica set consists of three servers, a primary, a secondary and an arbitrator. The primary and secondary both hold a copy of the data. The arbitrator is normally a low spec server which just monitors the other servers and help with the failover process. In production, there can be more than three servers.

To setup mongo as a replica set on Amazon Web Services EC2 you need to first setup a security group with ssh on port 22 and mongodb on port 27017. You then need to create three servers. Select Ubuntu 14.04 LTS x64 and a micro (or bigger depending on your database size, ideally you should have enough memory to match your database size) instance for the primary and secondary and a nano instance for the arbitrator.

##Adjust the File System on each Server The operating system by default will update the last access time on a file. In a high data throughput database application

mcastilho

package main

import (
	"bufio"
	"encoding/csv"
	"encoding/json"
	"fmt"
	"io"
	"os"
	"path/filepath"

harlow

Golang Workers / Job Queue

A running example of the code from:

• http://marcio.io/2015/07/handling-1-million-requests-per-minute-with-golang
• http://nesv.github.io/golang/2014/02/25/worker-queues-in-go.html

This gist creates a working example from blog post, and a alternate example using simple worker pool.

TLDR: if you want simple and controlled concurrency use a worker pool.

brianhempel

require "net/http"

def start_server
  # Remove the X to enable the parameters for tuning.
  # These are the default values as of Ruby 2.2.0.
  @child = spawn(<<-EOC.split.join(" "))
    XRUBY_GC_HEAP_FREE_SLOTS=4096
    XRUBY_GC_HEAP_INIT_SLOTS=10000
    XRUBY_GC_HEAP_GROWTH_FACTOR=1.8
    XRUBY_GC_HEAP_GROWTH_MAX_SLOTS=0

soheilhy

Virtual Hosts on nginx (CSC309)

When hosting our web applications, we often have one public IP address (i.e., an IP address visible to the outside world) using which we want to host multiple web apps. For example, one may wants to host three different web apps respectively for example1.com, example2.com, and example1.com/images on the same machine using a single IP address.

How can we do that? Well, the good news is Internet browsers

emad-elsaid

require 'socket'
require 'base64'

Refresh = 1 # seconds to refresh image on server
screen_capture_command = 'screencapture -C -x tmp.png'
image = ''
latest = Time.now
server = TCPServer.new 3000

loop do

josevalim

# Elixir v1.0
defmodule Rules do
  defmacro __using__(_) do
    quote do
      import unquote(__MODULE__)
      @before_compile unquote(__MODULE__)
      @rules []
    end
  end