isakbm / Learning-Ansible-Container

Learning Ansible-Container

Steps to get Ansible Container working

We are following this guide for instalation and an example setting up a flask server. Some of the steps are tricky due to incompatibilities with newer version of pip, etc

• Installation
• Getting Hello World Server Started

Installation

I did this on ubuntu xenial 16.04.4 LTS with the workon wrapper for virtualenv installed

$ virtualenv --version
15.0.1
$ virtualenv ansible-container
...
Installing setuptools, pkg_resources, pip, wheel...done.
$ workon ansible-container
$ pip install --upgrade pip==9.0.3
...
$ pip install ansible-container[docker]
$ pip install --upgrade docker==2.7.0

Once that is all done, you should have your ansible-container virtual environment ready to go.

Now let's proceed with getting the Hello World flask server up and running.

Getting Hello World Server Started

You will find all the necessary file content from this link.

First set up the project directory and initialize the ansible-container

$ mkdir hello-world
$ cd hello-world
$ ansible-container init
Ansible Container initialized.

Then make a requirements.txt file (to be used by python from inside the container later)

$ cat hello-world/requirements.txt

Flask=0.12.2
gunicorn=19.7.1

And the hello world flask script should also go in the hello-world directory, the file reads

from flask import Flask
app = Flask(__name__)

@app.route('/')
def hello_world():
    return 'Hello, World!'

We also need a role for the flask service, note that these commands are run inside the hello-world directory

$ mkdir roles
$ cd roles
$ ansible-galaxy init flask
- flask was created successfully

Now, the ansible recipe. First navigate to where it should be placed. That is, assuming you are in the hello-world directory do

$ cd roles/flask/tasks

You will see that there is already a main.yml file there. Replace it's contents with

---
- name: Install dumb init
  get_url:
    dest: /usr/bin/dumb-init
    url: https://github.com/Yelp/dumb-init/releases/download/v1.2.0/dumb-init_1.2.0_amd64
    mode: 0775
    validate_certs: no
- name: Install epel
  yum:
    name: epel-release
    state: present
    disable_gpg_check: yes
- name: Install pip
  yum:
    name: python2-pip
    state: present
    disable_gpg_check: yes
- name: Create flask user
  user:
    name: flask
    uid: 1000
    group: root
    state: present
    createhome: yes
    home: "/app"
- name: Copy source into container
  synchronize:
    src: "/src/"
    dest: "/app"
  remote_user: flask
- name: Install Python dependencies
  pip:
    requirements: /app/requirements.txt

Finally, navigating up again to the hello-world directory, modify the container.yml file to contain

version: "2"
settings:
  conductor:
    base: centos:7
  project_name: hello-world
  k8s_namespace:
     name: hello-world
     description: Simple Demo
     display_name: Hello, World
services:
  flask:
    from: centos:7
    roles:
      - flask
    entrypoint: /usr/bin/dumb-init
    command: gunicorn -w 4 -b 0.0.0.0:4000 helloworld:app
    ports:
      - 4000:4000
    working_dir: /app
    user: flask
registries: {}

And that's pretty much it, now build the container, and run it.

$ ansible-container build
...

$ ansible-container run
...

$ curl http://127.0.0.1:4000/
Hello, World!

You should also see it listed by running

$ docker ps
...