helm/examples/wordpress/README.md

# Wordpress Example

Welcome to the Wordpress example. It shows you how to deploy a Wordpress application using Deployment Manager.

## Prerequisites


### Deployment Manager
First, make sure DM is installed in your Kubernetes cluster by following the instructions in the top level
[README.md](../../README.md).

### Google Cloud Resources
The Wordpress application will make use of several persistent disks, which we will host on Google Cloud. To create these disks we will create a deployment using Google Cloud Deployment Manager: 
```gcloud deployment-manager deployments create wordpress-resources --config wordpress-resources.yaml```

where `wordpress-resources.yaml` looks as follows:

```
resources:
- name: nfs-disk
  type: compute.v1.disk
  properties:
    zone: us-central1-b
    sizeGb: 200
- name: mysql-disk
  type: compute.v1.disk
  properties:
    zone: us-central1-b
    sizeGb: 200
```

### Privileged containers
To use NFS we need to be able to launch privileged containers. If your Kubernetes cluster doesn't support this you can either manually change this in every Kubernetes minion or you could set the flag at `kubernetes/saltbase/pillar/privilege.sls` to true and (re)launch your Kubernetes cluster. Once Kubernetes 1.1 releases this should be enabled by default.


## Understanding the Wordpress example template

Let's take a closer look at the template used by the Wordpress example. The Wordpress application consists of 4 microservices: an nginx service, a wordpress-php service, a MySQL service, and an NFS service. The architecture looks as follows:

![Architecture](architecture.png)

### Variables
The template contains the following variables:

```
{% set PROJECT = properties['project'] or 'dm-k8s-testing' %}
{% set NFS_SERVER = properties['nfs-server'] or {} %}
{% set NFS_SERVER_IP = NFS_SERVER['ip'] or '10.0.253.247' %}
{% set NFS_SERVER_PORT = NFS_SERVER['port'] or 2049 %}
{% set NFS_SERVER_DISK = NFS_SERVER['disk'] or 'nfs-disk' %}
{% set NFS_SERVER_DISK_FSTYPE = NFS_SERVER['fstype'] or 'ext4' %}
{% set NGINX = properties['nginx'] or {} %}
{% set NGINX_PORT = 80 %}
{% set NGINX_REPLICAS = NGINX['replicas'] or 2 %}
{% set WORDPRESS_PHP = properties['wordpress-php'] or {} %}
{% set WORDPRESS_PHP_REPLICAS = WORDPRESS_PHP['replicas'] or 2 %}
{% set WORDPRESS_PHP_PORT = WORDPRESS_PHP['port'] or 9000 %}
{% set MYSQL = properties['mysql'] or {} %}
{% set MYSQL_PORT = MYSQL['port'] or 3306 %}
{% set MYSQL_PASSWORD = MYSQL['password'] or 'mysql-password' %}
{% set MYSQL_DISK = MYSQL['disk'] or 'mysql-disk' %}
{% set MYSQL_DISK_FSTYPE = MYSQL['fstype'] or 'ext4' %}
```

### Nginx service
The nginx service is a replicated service with 2 replicas:

```
- name: nginx
  type: https://raw.githubusercontent.com/leendersr/deployment-manager/master/types/replicatedservice/v2/replicatedservice.py
  properties:
    service_port: {{ NGINX_PORT }}
    container_port: {{ NGINX_PORT }}
    replicas: {{ NGINX_REPLICAS }}
    external_service: true
    image: gcr.io/{{ PROJECT }}/nginx:latest
    volumes:
      - mount_path: /var/www/html
        nfs:
          server: {{ NFS_SERVER_IP }}
          path: /
```

The nginx image builds upon the standard nginx image and simply copies a custom configuration file.

### Wordpress-php service
The wordpress-php service is a replicated service with 2 replicas:

```
- name: wordpress-php
  type: https://raw.githubusercontent.com/leendersr/deployment-manager/master/types/replicatedservice/v2/replicatedservice.py
  properties:
    service_name: wordpress-php
    service_port: {{ WORDPRESS_PHP_PORT }}
    container_port: {{ WORDPRESS_PHP_PORT }}
    replicas: 2
    image: wordpress:fpm
    env:
      - name: WORDPRESS_DB_PASSWORD
        value: {{ MYSQL_PASSWORD }}
      - name: WORDPRESS_DB_HOST
        value: mysql-service
    volumes:
      - mount_path: /var/www/html
        nfs:
          server: {{ NFS_SERVER_IP }}
          path: /
```

### MySQL service
The MySQL service is a replicated service with a single replica:

```
- name: mysql
  type: https://raw.githubusercontent.com/leendersr/deployment-manager/master/types/replicatedservice/v2/replicatedservice.py
  properties:
    service_port: {{ MYSQL_PORT }}
    container_port: {{ MYSQL_PORT }}
    replicas: 1
    image: mysql:5.6
    env:
      - name: MYSQL_ROOT_PASSWORD
        value: {{ MYSQL_PASSWORD }}
    volumes:
      - mount_path: /var/lib/mysql
        gcePersistentDisk:
          pdName: {{ MYSQL_DISK }}
          fsType: {{ MYSQL_DISK_FSTYPE }}
```         

### NFS service
The NFS service is a replicated service with a single replica:

```
- name: nfs-server
  type: https://raw.githubusercontent.com/leendersr/deployment-manager/master/types/replicatedservice/v2/replicatedservice.py
  properties:
    service_port: {{ NFS_SERVER_PORT }}
    container_port: {{ NFS_SERVER_PORT }}
    replicas: 1 # Has to be 1 because of the persistent disk
    image: jsafrane/nfs-data
    privileged: true
    cluster_ip: {{ NFS_SERVER_IP }}
    volumes:
      - mount_path: /mnt/data
        gcePersistentDisk:
          pdName: {{ NFS_SERVER_DISK }}
          fsType: {{ NFS_SERVER_DISK_FSTYPE }}
```          

## Deploying Wordpress
We can now deploy Wordpress using:

```
dm deploy examples/wordpress/wordpress.jinja
```