Customize Packages for Atomic Host : Ansible Automation

My earlier post automate-building-your-own-atomic-host describes how to Automate building Atomic Host with Ansible. But it is not capable of customizing packages for OSTree and build Atomic host based on it.

This post includes Ansible Automation for customizing packages of OSTree and build Atomic Host. Below are the improvements on this updated post :

  • Add packages to OSTree (It is suggested not to delete any pre-existing packages from the OSTree, that might break your Atomic host).
  • No need to create VM from the QCOW2 image will shell script anymore, It will be now all-in-one playbook.

If you do not know about Atomic host, please refer to http://www.projectatomic.io.

Requirements:

The requirements remain the same just like the earlier post. I will use Fedora distribution for the demo, but the same will be applicable for CentOS as well.

  • Make sure Ansible is installed on your system. If you are using Fedora workstation/any other platform, do not forget to install python2-dnf as well.
  • Download Atomic QCOW2 image: Fedora-Atomic.

Procedure:

Clone:

$ git clone https://github.com/trishnaguha/build-atomic-host.git
$ cd build-atomic-host/

Environment Setup:

The following will install requirements on your system, initializes OSTree and starts HTTP server as daemon service. The OSTree is made available via web server at TCP port 35000. After running the playbook you may use ip addr to check the IP Address of your HTTP server.

$ ansible-playbook setup.yml --ask-sudo-pass

Variables:

I am going to use variables applicable for Fedora. If you are using CentOS please modify the variables based on it.

  • Primary Variables.
    vars/atomic.yml
---
# Variables for Atomic host
atomicname: my-atomic                          # OSTree name
basehost: fedora-atomic/25/x86_64/docker-host  # Basehost
httpserver: 192.168.122.1                      # IP Address of HTTP Server
  • Additional packages you would like to have in your OSTree.
    vars/buildrepo.yml
# Variables for OSTree packages
repo: https://pagure.io/fedora-atomic.git
branch: f25
repodir: fedora-atomic
abs_path: /workspace                                # The absolute path to the git repo.
custommanifest: customized-atomic-docker-host.json  # The manifest that goes into the custom host(ostree) content that we are going to build.
sourcemanifest: fedora-atomic-docker-host.json      # The manifest that goes into the actual Base Fedora host(ostree) content.
packages: '"vim-enhanced", "git"'                   # Packages you want to have in your Atomic host.

Add packages like above separate by comma.

  • Variables for the VM
    vars/guests.yml
# Variables for Creating VM
domain: atomic-node                        # Domain name
image: Fedora-Atomic-25-20170228.0.x86_64  # Image name
cpu: 1
mem: 1536
os:
  variant: fedora23
path: /tmp                                 # Path to QCOW2 Image

Main Playbook:

Run the main Playbook which will create VM from QCOW2 image, compose OSTree and perform SSH-Setup and Rebase on OSTree:

$ ansible-playbook main.yml --ask-sudo-pass

Note: user-name: atomic-user, password: atomic are the credentials for the instance.
If you wish to change it, modify the cloud-init user-data.
We will have the credentials as variables/vault later.

To Check the IP Address of the VM running:

$ sudo virsh domifaddr atomic-node

Now SSH to the Atomic host and perform Reboot so that it will reboot in to custom OSTree.

$ ssh atomic-user@IP-ADDRESS-OF-VM
$ sudo systemctl reboot

SSH again and You will have your own OSTRee.

[atomic-user@atomic-node ~]$ sudo rpm-ostree status
State: idle
Deployments:
● my-atomic:fedora-atomic/25/x86_64/docker-host
       Version: 25.1 (2017-02-07 05:34:46)
        Commit: 15b70198b8ec7fd54271f9672578544ff03d1f61df8d7f0fa262ff7519438eb6
        OSName: fedora-atomic

  fedora-atomic:fedora-atomic/25/x86_64/docker-host
       Version: 25.51 (2017-01-30 20:09:59)
        Commit: f294635a1dc62d9ae52151a5fa897085cac8eaa601c52e9a4bc376e9ecee11dd
        OSName: fedora-atomic
[atomic-user@atomic-node ~]$ rpm -q git vim-enhanced
git-2.9.3-2.fc25.x86_64
vim-enhanced-8.0.386-1.fc25.x86_64

If you find any bug/idea please open up issues here. Thanks.

Atomic-Host

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Containerization and Deployment of Application on Atomic Host using Ansible Playbook

This article describes how to build Docker image and deploy containerized application on Atomic host (any Remote host) using Ansible Playbook.

Building Docker image for an application and run container/cluster of containers is nothing new. But the idea is to automate the whole process and this is where Ansible playbooks come in to play.

Note that you can use Cloud/Workstation based Image to execute the following task. Here I am issuing the commands on Fedora Workstation.

Let’s see How to automate the containerization and deployment process for a simple Flask application:

We are going to deploy container on Fedora Atomic host.

First, Let’s Create a simple Flask Hello-World Application.

This is the Directory structure of the entire Application:

flask-helloworld/
├── ansible
│   ├── ansible.cfg
│   ├── inventory
│   └── main.yml
├── Dockerfile
└── flask-helloworld
    ├── hello_world.py
    ├── static
    │   └── style.css
    └── templates
        ├── index.html
        └── master.html

hello_world.py

from flask import Flask, render_template

APP = Flask(__name__)

@APP.route('/')
def index():
    return render_template('index.html')

if __name__ == '__main__':
    APP.run(debug=True, host='0.0.0.0')

static/style.css

body {
  background: #F8A434;
  font-family: 'Lato', sans-serif;
  color: #FDFCFB;
  text-align: center;
  position: relative;
  bottom: 35px;
  top: 65px;
}
.description {
  position: relative;
  top: 55px;
  font-size: 50px;
  letter-spacing: 1.5px;
  line-height: 1.3em;
  margin: -2px 0 45px;
}

templates/master.html

<!doctype html>
<html>
<head>
    {% block head %}
    <title>{% block title %}{% endblock %}</title>
    {% endblock %}
    												<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" integrity="sha384-1q8mTJOASx8j1Au+a5WDVnPi2lkFfwwEAa8hDDdjZlpLegxhjVME1fgjWPGmkzs7" crossorigin="anonymous">
    												<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.6.3/css/font-awesome.min.css" rel="stylesheet" integrity="sha384-T8Gy5hrqNKT+hzMclPo118YTQO6cYprQmhrYwIiQ/3axmI1hQomh7Ud2hPOy8SP1" crossorigin="anonymous">
    												<link rel="stylesheet" href="{{ url_for('static', filename='style.css') }}">
    												<link href='http://fonts.googleapis.com/css?family=Lato:400,700' rel='stylesheet' type='text/css'>

</head>
<body>
<div id="container">
    {% block content %}
    {% endblock %}</div>
</body>
</html>

templates/index.html

{% extends "master.html" %}

{% block title %}Welcome to Flask App{% endblock %}

{% block content %}
<div class="description">

Hello World</div>
{% endblock %}

Let’s write the Dockerfile.

FROM fedora
MAINTAINER Trishna Guha<tguha@redhat.com>

RUN dnf -y update && dnf -y install python-flask python-jinja2 && dnf clean all
RUN mkdir -p /app

COPY files/ /app/
WORKDIR /app

ENTRYPOINT ["python"]
CMD ["hello_world.py"]

Now we will work on Ansible playbook for our application that deals with the automation part:

Create inventory file:

[atomic]
IP_ADDRESS_OF_HOST ansible_ssh_private_key_file=<'PRIVATE_KEY_FILE'>

Replace IP_ADDRESS_OF_HOST with the IP address of the atomic/remote host and ‘PRIVATE_KEY_FILE’ with your private key file.

Create ansible.cfg file:

[defaults]
inventory=inventory
remote_user=USER

[privilege_escalation]
become_method=sudo
become_user=root

Replace USER with the user of your remote host.

Create main.yml file:

---
- name: Deploy Flask App
  hosts: atomic
  become: yes

  vars:
    src_dir: [Source Directory]
    dest_dir: [Destination Directory]

  tasks:
    - name: Create Destination Directory
      file:
       path: "{{ dest_dir }}/files"
       state: directory
       recurse: yes

    - name: Copy Dockerfile to host
      copy:
       src: "{{ src_dir }}/Dockerfile"
       dest: "{{ dest_dir }}"

    - name: Copy Application to host
      copy:
       src: "{{ src_dir }}/flask-helloworld/"
       dest: "{{ dest_dir }}/files/"

    - name: Make sure that the current directory is {{ dest_dir }}
      command: cd {{ dest_dir }}

    - name: Build Docker Image
      command: docker build --rm -t fedora/flask-app:test -f "{{ dest_dir }}/Dockerfile" "{{ dest_dir }}"

    - name: Run Docker Container
      command: docker run -d --name helloworld -p 5000:5000 fedora/flask-app:test
...

Replace [Source Directory] in src_dir field in main.yml with your /path/to/src_dir of your current host.

Replace [Destination Directory] in dest_dir field in main.yml with your /path/to/dest_dir of your remote atomic host.

Now simply run $ ansible-playbook main.yml :).  To verify if the application is running issue this command $ curl http://localhost:5000 on your atomic/remote host.

You can also manage your containers running on remote host using Cockpit. Check this article to know how to use Cockpit to manage your containers: https://fedoramagazine.org/deploy-containers-atomic-host-ansible-cockpit

fotoflexer_photo

screenshot-from-2016-10-21-18-52-45

Here is the repository of the above example:  https://github.com/trishnaguha/fedora-cloud-ansible/tree/master/examples/flask-helloworld

My future post will be related to ansible-container where I will describe how we can build Docker image and orchestrate container without writing any Dockerfile :).