Josemar Furegatti de Abreu Silva: 2017

sexta-feira, 29 de dezembro de 2017

1. Introduction

This post gathers information about SQL Training, abording fundamental questions.

2. References

https://github.com/josemarsilva/treina-sql-I/wiki

quarta-feira, 20 de dezembro de 2017

How to Use Windows 8 Performance Monitor to Analyse Your System Performance

1. Introduction

This post shows step-by-step how to configure Windows environment to collect performance counters.

2. Step by Step

2.1. Before Starting

Performance tunning process is a cycle process. Maybe you don't find your major bootleneck on the first time, so you will need to iterate and refine performance counters until find it.

2.1. How to have a Quick Wins of performance

Run Task Manager (taskmgr)

2.2. How to configure Windows Performance Monitor to Analyze your System Performance

3. References

domingo, 5 de novembro de 2017

1. Introduction

This post shows how to install Nexus on Ubuntu 16.04

2. Step by Step

2.1. Download install binary

$ cd /tmp
$ wget http://download.sonatype.com/nexus/3/nexus-3.6.0-02-unix.tar.gz

2.2. Install Nexus on /opt/nexus

$ tar -xvzf nexus-3.6.0-02-unix.tar.gz

$ sudo mv /tmp/nexus-3.6.0-02 /opt

$ sudo mv /opt/nexus-3.6.0-02 /opt/nexus

2.3. Configure Nexus

a) Configure Nexus Port

$ sudo cp /opt/nexus/etc/nexus-default.properties /opt/nexus/etc/nexus-default.properties.bkp.2017-11-05 # take a backup

$ sudo vim /opt/nexus/etc/nexus-default.properties
:
application-port=8081
:

b) Add firewall rule to accept incomming call on nexus port 8081

$ sudo ufw allow 8081

c) Configure Nexus script - run_as_user

$ sudo cp /opt/nexus/bin/nexus /opt/nexus/bin/nexus.bkp.2017-11-05 # backup
$ sudo vim /opt/nexus/bin/nexus
:
# user to execute as; optional but recommended to set
run_as_user='nexus'
NEXUS_HOME="/opt/nexus"
:

d) Configure nexus users and group

$ sudo adduser --no-create-home --disabled-login --disabled-password nexus
Adding user `nexus' ...
Adding new group `nexus' (1002) ...
Adding new user `nexus' (1002) with group `nexus' ...
Not creating home directory `/home/nexus'.
Changing the user information for nexus
:
Is the information correct? [Y/n] Y

e) Set files permission '/opt/nexus'

$ sudo chown -R nexus:nexus /opt/nexus

2.4. Deploying nexus and sonatype-work directories

$ sudo mkdir /var/lib/nexus

$ sudo mkdir /var/lib/nexus/sonatype-work

$ sudo chown -R nexus:nexus /var/lib/nexus

2.5. Run Nexus and check

$ su - nexus
$ whoami
nexus
$ /opt/nexus/bin/nexus start

3. References

https://www.build-business-websites.co.uk/install-nexus-on-ubuntu-16-04/

Installing Tomcat 8 on Ubuntu Server 16.04

1. Introduction

This post shows step by step how to install Tomcat into Ubuntu Server 16.04.

2. Step-by-Step

2.1. Update system packages

$ sudo apt-get update

2.2 Create Tomcat User and Group

a) Create 'tomcat' Group

$ sudo groupadd tomcat

b) Create 'tomcat' Group

$ sudo useradd -s /bin/false -g tomcat -d /opt/tomcat tomcat

2.3 Download Tomcat installer from mirror site

a) Open Tomcat mirror site in your browser and find out current available download version

+---------------------------------------------------------------------------------+

| http://apache.mirrors.ionfish.org/tomcat/tomcat-8/ |

+---------------------------------------------------------------------------------+

| Index of /tomcat/tomcat-8 |

| |

| Name Last modified Size Description |

| ../ - |

| v8.0.47/ 03-Oct-2017 08:50 - |

| v8.5.23/ 01-Oct-2017 18:31 - |

| |

| Apache Server at apache.mirrors.ionfish.org Port 80 |

+---------------------------------------------------------------------------------+

2.4 Download Tomcat install tar.gz for linux

$ cd /tmp

$ curl -O http://apache.mirrors.ionfish.org/tomcat/tomcat-8/v8.5.23/bin/apache-tomcat-8.5.23.tar.gz

2.5. Install Tomcat 8 into /opt/tomcat

a) Unzipping into /opt/tomcat

$ sudo mkdir /opt/tomcat
$ sudo tar xzvf apache-tomcat-8*tar.gz -C /opt/tomcat --strip-components=1

b) Adjusting permisson for 'tomcat' user

$ cd /opt/tomcat
$ sudo chgrp -R tomcat /opt/tomcat

$ sudo chmod -R g+r conf

$ sudo chmod g+x conf

$ sudo chown -R tomcat webapps/ work/ temp/ logs/

2.6. Create a systemd Service file for Tomcat

a) Checking JAVA_HOME

$ sudo update-java-alternatives -l
java-1.8.0-openjdk-amd64 1081 /usr/lib/jvm/java-1.8.0-openjdk-amd64

b) Create systemd service file on /etc/systemd/system/tomcat

$ sudo vim /etc/systemd/system/tomcat.service

[Unit]

Description=Apache Tomcat Web Application Container

After=network.target

[Service]

Type=forking

Environment=JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-amd64

Environment=CATALINA_PID=/opt/tomcat/temp/tomcat.pid

Environment=CATALINA_HOME=/opt/tomcat

Environment=CATALINA_BASE=/opt/tomcat

Environment='CATALINA_OPTS=-Xms512M -Xmx1024M -server -XX:+UseParallelGC'

Environment='JAVA_OPTS=-Djava.awt.headless=true -Djava.security.egd=file:/dev/./urandom'

ExecStart=/opt/tomcat/bin/startup.sh

ExecStop=/opt/tomcat/bin/shutdown.sh

User=tomcat

Group=tomcat

UMask=0007

RestartSec=10

Restart=always

[Install]

WantedBy=multi-user.target

c) Reload systemd service to apply change

$ sudo systemctl daemon-reload

$ sudo systemctl start tomcat

d) Configure tomcat service to automatically starts on boot

$ sudo systemctl enable tomcat

e) Manually starting, stopping and status

$ sudo /opt/tomcat/bin/catalina.sh start
$ sudo /opt/tomcat/bin/catalina.sh stop
$ sudo /opt/tomcat/bin/catalina.sh status

2.7. Ajust firewall rule

a) Checking if

$ service ufw status
ufw.service - Uncomplicated firewall
Loaded: loaded (/lib/systemd/system/ufw.service; enabled; vendor preset: enab
Active: active (exited) since Sun 2017-11-05 19:17:17 BRST; 12min ago
Process: 376 ExecStart=/lib/ufw/ufw-init start quiet (code=exited, status=0/SU
:

b) Add firewall rule to accept incomming call on Tomcat port 8080

$ sudo ufw allow 8080

2.8. Configure Tomcat Web Management Interface

a) Edit tomcat-users.xml, be carefull with remarks ""

$ sudo vim /opt/tomcat/conf/tomcat-users.xml
:
<tomcat-users xmlns="http://tomcat.apache.org/xml"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://tomcat.apache.org/xml tomcat-users.xsd"
version="1.0">

:
<user username="admin" password="admin" roles="manager-gui,admin-gui,tomcat"/>

:
</tomcat-users>

b) Edit context.xml,

$ sudo vim /opt/tomcat/webapps/host-manager/META-INF/context.xml
:
<Context antiResourceLocking="false" privileged="true" >
<Valve className="org.apache.catalina.valves.RemoteAddrValve"
allow="127\.\d+\.\d+\.\d+|::1|0:0:0:0:0:0:0:1" />
<Manager sessionAttributeValueClassNameFilter="java\.lang\.(?:Boolean|Integer|Long|Number|String)|org\.apache\.catalina\.filters\.CsrfPreventionFilter\$LruCache(?:\$1)?|java\.util\.(?:Linked)?HashMap"/>
</Context>

2.9. Open Tomcat in browser

a) Open default Tomcat page

http://localhost:8080

b) Open Tomcat Documentation page

http://127.0.0.1:8080/docs/

3. References

Installing OpenJDK (8 default for Ubuntu 16.04)

1. Introduction

This post shows how to install Open JDK 8 default for Ubuntu 16.04.

2. Step By Step

2.1. Update package list

$ sudo apt-get update

2.2. Install Java JDK 8 default

$ sudo apt-get install default-jdk

2.3. Testing Java Compiler

$ javac -version

3. References

quinta-feira, 2 de novembro de 2017

Install Jenkins on Ubuntu 16.04

1. Introduction

2. Step by Step

2.1. Prerequisites

2.1.a. Check Memory available

1 GB of RAM minimum;
4 GB desired;

2.1.b. System Update

$ sudo apt-get update

2.2. Install Jenkins

$ wget -q -O - https://pkg.jenkins.io/debian/jenkins-ci.org.key | sudo apt-key add -
OK
$ cat /etc/apt/sources.list.d/jenkins.list
deb http://pkg.jenkins.io/debian-stable binary/
$ sudo apt-get update

2.3. Upgrade Jenkins version ( optional )

$ sudo apt-get update
$ sudo apt-get install jenkins

2.4. Cheking services

$ # Ubuntu/Debian (different from CentOs/Fedora) usually starts software after installation
$ # Jenkins will be started as a deamon service named 'jenkins'
$ # See /etc/init.d/jenkins for more details. Log file will be placed in /var/log/jenkins/jenkins.log.
$ # Config parameters like JENKINS_HOME and etc, will be captured on /etc/default/jenkins
$ # By default, Jenkins listen on port 8080. Edit /etc/default/jenkins to change port
$ # To start-stop-status service do: sudo service jenkins stop; sudo service jenkins start; sudo service jenkins status

2.5. Check/allow firewall rules

a) Check firewall status - Inactive? Great nothing to do

$ sudo ufw status
Status: inactive

b) Check firewall status - Active? add rule to allows Jenkins port

$ sudo ufw status
Status: active
:
8080 ALLOW Anywhere
:
$ sudo ufw allow 8080

2.6. Setting up Jenkins

a) Access Jenkins interface on browser and you'll see "Unlock Jenkins screen"

http://localhost:8080

b) Install suggested plugins

+------------------------------------------------+
| Customize Jenkins |
| +------------------+ |
| |Install Suggested | |
| | Pluggins | | <- click button
| +------------------+ |
+------------------------------------------------+

c) Create first admin user

3. References

quinta-feira, 20 de julho de 2017

Manipulating text files on linux

1. Introdução

This post gathers information about how to manipulates text files on linux systems.

2. Referências

http://terminalroot.com.br/2015/07/30-exemplos-do-comando-sed-com-regex.html

terça-feira, 18 de julho de 2017

How to Increase the size of a Linux LVM by adding a new disk

1. Introduction

This post olny gathers information about how to increase size linux LVM.

2. References

* https://www.rootusers.com/how-to-increase-the-size-of-a-linux-lvm-by-adding-a-new-disk/

sexta-feira, 2 de junho de 2017

DOCKER Faq, HowTo, Referece, Sample Install Run PostgreSQL in a Docker

1. Introduction

This post gathers information about PostgreSQL and Docker.

2. Step-by-Step

2.1. Ensure Docker, Docker Compose are working

# docker --version
Docker version 17.03.1-ce, build c6d412e
# docker-compose --version
docker-compose version 1.11.2, build dfed245

2.2. Install a PostgreSQL Docker

Determining PostgreSQL Docker Version to install

# psql --version
psql (PostgreSQL) 9.6.3

Pull docker image versions

# docker pull postgres:9.6.3-alpine
# docker pull postgres:9.6.3

Run PostgreSQL Docker Image in background - database instance

# docker run --name postgres-01 -e POSTGRES_PASSWORD=mysecretpassword -d postgres:9.6.3-alpine
# docker run --name postgres-02 -e POSTGRES_PASSWORD=mysecretpassword -d postgres:9.6.3

Check both Docker process images running

# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
676278f9f054 postgres:9.6.3 "docker-entrypoint..." 7 seconds ago Up 7 seconds 5432/tcp postgres-02
0d93213e347e postgres:9.6.3-alpine "docker-entrypoint..." 12 seconds ago Up 11 seconds 5432/tcp postgres-01

Stop Docker instance "postgres-02"

# docker stop postgres-02
# docker kill postgres-02

Run PostgreSQL psql command line, linked to running instance "postgres-01", using interative mode. Interate with application saying the password "mysecretpassword"

# docker run --name postgres-psql-01 -it --rm --link postgres-01:postgres postgres psql -h postgres-01 -U postgres:9.6.3-alpine
Password for user postgres: mysecretpassword
psql (9.6.3)
Type "help" for help.

postgres=# select current_date;
date
------------
2017-06-03

(1 row)

postgres=# \q

Run PostgreSQL plsql command line, linked to running instance "postgres-01", using interative mode, using password in command line

3. References

RAILS Faq, HowTo, Reference, Sample Setup a Rails App With Apache and Passenger on CentOS 6

1. Introduction

This post gathers information about how to setup RAILS APP with Apache and Passenger on CentOS 6.

2. Step-by-Steyp

Step#1: First of all, mantain your linux so up-to-date

# yum update

Step#2: Install Apache

# yum install httpd

Step#3: Install apache

# yum install httpd curl-devel httpd-devel

Step#4: Get Apache to start on boot:

# chkconfig httpd on

Step#5: Install Phusion Passenger and dependency packages

# gem install passenger
# yum install curl-devel httpd-devel

Step#6: Compile the environment:

# passenger-install-apache2-module

Step#7 Edit the Apache config file in etc/httpd/conf/httpd.conf

Uncomment the line containing NameVirtualHost *:80 towards the end
Paste the output from (Step#6 Compile environment) anywhere at the end of the file, eg:

# vim etc/httpd/conf/httpd.conf

LoadModule passenger_module /usr/local/rvm/gems/ruby-2.1.1/gems/passenger-4.0.41/buildout/apache2/mod_passenger.so

PassengerRoot /usr/local/rvm/gems/ruby-2.1.1/gems/passenger-4.0.41

PassengerDefaultRuby /usr/local/rvm/gems/ruby-2.1.1/wrappers/ruby

ServerName 1.2.3.4 # www.whatever.com

DocumentRoot /var/www/rails/public # the path to your rails app

AllowOverride all

Options -MultiViews

</Directory>

</VirtualHost>

3. References

https://www.digitalocean.com/community/tutorials/how-to-setup-a-rails-4-app-with-apache-and-passenger-on-centos-6
https://stackoverflow.com/questions/5584759/start-rails-server-automatically-after-boot

terça-feira, 23 de maio de 2017

RAILS Faq HowTo Reference Sample Using scopes on Rails to Filter index page and Re-display filter inputs

1. Introduction

This post gathers information about FAQ-Frequently Asked Question, How To, technical document references and samples about these RAILS topics.

Using scopes on Rails to Filter index page and Re-display filter inputs

2. FAQ, HOWTO, REFERENCES, SAMPLES, etc

2.1. Create model scopes for each filter condition

# vim app/models/cluster_config.rb

class ClusterConfig < ApplicationRecord

include Filterable

scope :cluster_config, -> (id) { where id: id}

scope :cluster_status, -> (cluster_status_id) { where cluster_status_id: cluster_status_id}

scope :cluster_environment_type, -> (cluster_environment_type_id) { where cluster_environment_type_id: cluster_environment_type_id}

scope :cluster_content_type, -> (cluster_content_type_id) { where cluster_content_type_id: cluster_content_type_id}

end

2.2. Implement generic filter on model concerns

# vim app/models/concerns/filterable.rb

module Filterable

extend ActiveSupport::Concern

module ClassMethods

def filter(filtering_params)

results = self.where(nil)

filtering_params.each do |key, value|

results = results.public_send(key, value) if value.present?

end

results

end

2.3. Implement filter on index controller

# vim app/controllers/cluster_configs_controller.rb

class ClusterConfigsController < ApplicationController

before_action :set_cluster_config, only: [:show, :edit, :update, :destroy]

def index

@cluster_configs = ClusterConfig.filter(params.slice(:cluster_config, :cluster_status, :cluster_environment_type, :cluster_content_type)).paginate(page: params[:page], per_page: 20)

end

private

def set_cluster_config

@cluster_config = ClusterConfig.find(params[:id])

end

def cluster_config_params

params.require(:cluster_config).permit(:cluster_status_id, :cluster_environment_type_id, :cluster_content_type_id, :url_rest_service, :db_host, :db_port, :db_name, :dt_created, :dt_delivered, :obs)

end

2.4. Implement filter on index viewer

# vim app/views/cluster_configs/index.html.erb

<h3>Filter by:</h3>

<%= form_for cluster_configs_path do %>

<div>

Id: <%= text_field_tag 'cluster_config', '' %>

Status Massa: <%= select("cluster_status", "cluster_status", ClusterStatus.all.map {|a| [a.cluster_status, a.id] }, { include_blank: true }) %>

Environment Type: <%= select("cluster_environment_type", "cluster_environment_type", ClusterEnvironmentType.all.map {|a| [a.cluster_environment_type, a.id] }, { include_blank: true }) %>

Content Type: <%= select("cluster_content_type", "cluster_content_type", ClusterContentType.all.map {|a| [a.cluster_content_type, a.id] }, { include_blank: true }) %>

<%= submit_tag 'Filter' %>

</div>

<% end %>

2.5. Erro

Error when "Filter" submit button

ActionController::ParameterMissing in ClusterConfigsController#create

param is missing or the value is empty: cluster_config

Extracted source (around line #73):

72: def cluster_config_params

73: params.require(:cluster_config).permit(:cluster_status_id, :cluster_environment_type_id, :cluster_content_type_id, :url_rest_service, :db_host, :db_port, :db_name, :dt_created, :dt_delivered, :obs)

74: end

Request

Parameters:

{"utf8"=>"✓",

"authenticity_token"=>"BF22bYvS/UXHOgeLLXeindCqWeXj41w/MxPE93cNoLBnaGwMhdC+HOuvvc6TCoteFHTsyyCZsoxO2j0kA4q/yA==",

"cluster_config"=>"",

"cluster_status"=>{"cluster_status"=>""},

"cluster_environment_type"=>{"cluster_environment_type"=>""},

"cluster_content_type"=>{"cluster_content_type"=>""},

"commit"=>"Filter"}

3. References

segunda-feira, 22 de maio de 2017

RAILS Faq HowTo Reference Sample Bootstrap Navbar with RAILS

1. Introduction

This post gathers information about FAQ-Frequently Asked Question, How To, technical document references and samples about these RAILS topics.
* Bootstrap Navbar with RAILS

2. FAQ, HOWTO, REFERENCES, SAMPLES, etc

2.1. Bootstrap Navbar with RAILS

a) HOWTO

a.1) Setp #1: Find Gemfile configuration

Open rubygems and search for "bootstrap-sass"

https://rubygems.org/
[ bootstrap-sass ] | Search

You should be redirect to https://rubygems.org/gems/bootstrap-sass
Copy gemfile command on the left corner, something like "gem 'bootstrap-sass', '~> 3.3', '>= 3.3.7'"
Edit ./Gemfile on your project root and add bootstrap-sass

a.2) Setp #2: Configure your project Gemfile

$ cd ~/myrailsproject
$ vim Gemfile
:
# Josemarsilva - 2017-05-19 - http://www.rubydoc.info/gems/bootstrap-sass/3.3.7#a-ruby-on-rails
gem 'bootstrap-sass', '~> 3.3', '>= 3.3.7'
gem 'sass-rails', '~> 5.0'

a.3) Setp #3: Configure your project Gemfile and

# bundle install

a.4) Step #4: Hide default "application.css" and configure "application.scss"

# mv app/assets/stylesheets/application.css app/assets/stylesheets/application.css.hidden-by-bootstrap
# vim app/assets/stylesheets/application.scss
+----------------------------------------------------------------------------------------+
|// "bootstrap-sprockets" must be imported before "bootstrap" and "bootstrap/variables" |
|$icon-font-path: "bootstrap-sass/assets/fonts/bootstrap/"; |
|@import "bootstrap-sprockets"; |
|@import "bootstrap"; |
+----------------------------------------------------------------------------------------+

a.5) Step #5: configure "application.js"

# vim app/assets/javascripts/application.js
+----------------------------------------------------------------------------------------+
|// JosemarSilva 2017-05-19 http://www.rubydoc.info/gems/bootstrap-sass/3.3.7 |
|//= require bootstrap |
|//= require jquery |
|//= require jquery_ujs |
|//= require turbolinks |
|//= require bootstrap-sprockets |
|//= require_tree . |
+----------------------------------------------------------------------------------------+

a.6) Step #6: configure "app/views/layouts/application.html.erb"

a.7) Step #7: configure Navbar on header part template using bootstrap

Open Bootstrap Navbar documentation and copy example

http://getbootstrap.com/components/#navbar

Paste example into '_header.html.erb' part