Category: Computer

Computer is miraculous!

Learning – Introduction to AWS Services

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Learning - Introduction to AWS Services

AWS Global Datacenter

  • AWS Account - Global (Billing, IAM, Route53)
  • Regions - Independent Geographic Area (S3, CDN, DynamoDB)
  • VPCs (ELB)
  • Availability Zones - Multiple isolated locations / data centers within a region (EC2, RDS, EBS)
  • Edge locations
  • Ragional Caches
  • Services

Storage

References

Introduction to AWS Services

Learning – Ansible 101 – Episode 2 – Ad-hoc tasks and Inventory

Posted on by Bian Xi Leave a Comment on Learning – Ansible 101 – Episode 2 – Ad-hoc tasks and Inventory

Learning - Ansible 101 - Episode 2 - Ad-hoc tasks and Inventory

Run ad-hoc tasks using Ansible.

Vagrant Cloud

Vagrant init

vagrant init geerlingguy/centos7

Vagrantfile

Vagrant.configure("2") do |config|
  config.vm.box = "geerlingguy/centos7"

  config.ssh.insert_key = false

  config.vm.synced_folder ".", "/vagrent", disabled: true

  config.vm.provider :virtualbox do |v|
    v.memory= 256
    v.linked_clone = true
  end

  # App server 1
  config.vm.define "app1" do |app|
    app.vm.hostname = "orc-app1.test"
    app.vm.network :private_network, ip: "192.168.60.4"
  end

  # App server 2
  config.vm.define "app2" do |app|
    app.vm.hostname = "orc-app2.test"
    app.vm.network :private_network, ip: "192.168.60.5"
  end

  # DB server
  config.vm.define "db" do |db|
    db.vm.hostname = "orc-db.test"
    db.vm.network :private_network, ip: "192.168.60.6"
  end
end
vagrant up

Create inventory file

# Application servers
[app]
192.168.60.4
192.168.60.5

# Database server
[db]
192.168.60.6

# Group has all the servers
[multi:children]
app
db

# Variable for all the servers
[multi:vars]
ansible_ssh_user=vagrant
ansible_ssh_private_key_file=~/.vagrant.d/insecure_private_key

Run Ansible

ansible multi -i inventory -a "hostname"

Note: accept host key if prompt, or change the .ssh/config file to ignore host key

To run one by one,

ansible multi -i inventory -a "hostname" -f 1

Run ansible to query configuration

ansible -i inventory db -m setup

Install NTP

ansible -i inventory multi -b -m yum -a "name=ntp state=present"

ansible -i inventory multi --become -m yum -a "name=ntp state=present"

Note: Run the second time, the status will be SUCCESS, not CHANGED

Ask for sudo password

ansible -i inventory multi -K -m yum -a "name=ntp state=present"

Note: for this image, the vagrant user has password vargent

Check service status

ansible -i inventory multi -b -m service -a "name=ntpd state=started enabled=yes"

Check service options

  • Use google search "ansible service module".

  • Use ansible-doc command

ansible-doc service

NTP commands

ansible -i inventory multi -b -a "service ntpd stop"
ansible -i inventory multi -b -a "ntpdate -q 0.rhel.pool.ntp.org"

my_sql

Setup user on mysql server.

ansible -i inventory db -b -m mysql_user -a "name=django host=% password=12345 priv=*.*:ALL state=present"

Limit to one server

ansible -i inventory multi -a "free -m" --limit '192.168.60.4'
ansible -i inventory multi -a "free -m" --limit '*.4'
ansible -i inventory multi -a "free -m" --limit '!192.168.60.4'
ansible -i inventory multi -a "free -m" --limit '!192.168.60.4:!192.168.60.5'

References

Ansible 101 - Episode 2 - Ad-hoc tasks and Inventory

Learning – Ansible 101 – Episode 1 – Introduction to Ansible

Posted on by Bian Xi Leave a Comment on Learning – Ansible 101 – Episode 1 – Introduction to Ansible

Learning - Ansible 101 - Episode 1 - Introduction to Ansible

Introduction to Ansible

Installation

pip3 install ansible
ansible --version

Create inventory file

Create a file called inventory

[example]
107.20.106.183

Run command

ansible -i inventory example -m ping -u centos

Create ansible.cfg file

[defaults]
INVENTORY=inventory

Run command with not inventory option

ansible example -m ping -u centos

Run ad-hoc commnad

ansible example -a "date" -u centos
ansible example -a "free -h" -u centos

In fact, above commands used default module -m command, and the -a option is giving the command arguments.

Install VirtualBox and Vagrant

Then initialize vagrant

vagrant init geerlingguy/centos7

This will create a file called Vagrantfile in current directory.

Vargent VM commands

  • create vm
vagrant up
  • ssh into vm
vagrant ssh
  • show ssh configuration
vagrant ssh-config

This configuration can be used to update ssh configuration

  • shutdown vm
vagrant halt
  • delete vm
vagrant destroy

Create Vagrantfile

Vagrant.configure("2") do |config|
  config.vm.box = "geerlingguy/centos7"

  config.vm.provsion "ansible" do |ansible|
    ansible.playbook = "playbook.yml"
  end
end

Create playbook.yml

---
- name: Set up NTP on all servers.
  hosts: all
  become: yes
  tasks:
    - name: Ensure NTP is installed.
      yum: name=ntp state=present
    - name: Ensure NTP is running.
      service: name=ntpd state=started enabled=yes

The name is optional

    - yum: name=ntp state=present
    - service: name=ntpd state=started enabled=yes

Run provision command

vagrant provision

Idempotence

The command can be run many times without change the result if success before.

But following command in playbook will run every time when triggered playbook.

  - command: yum install -y ntp

To overcome this, change to following

  - shell: |
      if ! rpm -qa | grep -qw ntp; then
        yum install -y ntp
      fi

References

Ansible 101 - Episode 1 - Introduction to Ansible

Create Multi Related Posts in WordPress

Posted on by Bian Xi Leave a Comment on Create Multi Related Posts in WordPress

Create Multi Related Posts in WordPress

Create a Post with Posts List

# <Post Title> - Posts List

<Post contain>

## References

[<SubPost_Title1>](<SubPost_URL1>)
[<SubPost_Title2>](<SubPost_URL2>)
[<SubPost_Title3>](<SubPost_URL3>)
[<SubPost_Title4>](<SubPost_URL4>)

SubPost

Add following script after each subpost summary.

Note: The 8888 is the subpost id, 9999 is the index post (Posts List) id. This will create a button on current page (8888) to display Posts List

# <Post Title>

<Post contain>

<div><button id='related_posts_8888'>Display Learning Posts</button>

<script type="text/javascript">
(function($) {
    $(document).ready(function() {
        $("#related_posts_8888").click(function(event) {
            el = $(document.getElementById( $(this).attr('id') ).parentElement);
            $.get("?p=9999", function(data, status) {
                el.html(/h2>References<\/h2>([\s\S]*?)<\/div>/.exec(data)[1]);
            });
        });
    });
}) (jQuery);
</script>
</div>