**************************************
Step 3: Load a Simple Docker Project
**************************************

.. include:: urls.rst

.. contents:: Table of Contents

Snap applications are easy to install because they take care
of all of the dependencies and run them in a semi-isolated environment.

* One drawback is that the application is tightly integrated.
  Configuring it or modifying it to use a different component is hard to do.
* It's not practical to use ``snaps`` to run part of the application on
  one box and then have the database on another server. Or, you might not
  be able to use MariaDB instead of the pre-configured MySQL instance.

Docker containers address these problems. Like snaps, Docker containers
run in isolation, meaning they will not conflict with services running
on the host machine.

   a. For this step, we will run the Docker-based application in a
      similar fashion to how snaps operate.
   #. We still have the problem of one application per box, but this
      moves us closer to distributed computing because Docker lets
      developers spread or distribute the components across different
      containers.

This Docker project works in isolation. It is a single container that
contains the webserver, database, and all of the data.

Installing NextCloud on Docker
===============================
|Nextcloud| is an open-source tool for cloud storage. It has web,
desktop, and mobile applications.

   * This installation is for demonstration purposes only.
   * We will do a production-ready install later so you can use to
     store your data in the cloud

We'll use the instruction from |https://github.com/nextcloud/docker|
to run NextCloud in Docker.

#. Run the Docker container

   * The command has these arguments:

     ``run -d``
         Runs the container in daemon mode, which means running it in
         the background

     ``-p 20850:80``
         The port pairs.

         * The first port (20850) is the external port, which is
           accessible to the VPS.
         * The second port (80) is internal to the Docker container.

     ``nextcloud``
         Name of the container to run. This container is pulled from
         |Docker Hub|.

   .. code-block:: bash

       docker run -d -p 20850:80 nextcloud

   .. code-block:: bash
       :caption: Output
       :emphasize-lines: 1

       root@vps298933:~# docker run -d -p 20850:80 nextcloud
       Unable to find image 'nextcloud:latest' locally
       latest: Pulling from library/nextcloud
       f7e2b70d04ae: Pull complete
       744aedb7995c: Pull complete
       07afe22f8a58: Pull complete
       c7bf4f31c4a4: Pull complete
       b528e75732cc: Pull complete
       27e7d214ded2: Pull complete
       894549c23c16: Pull complete
       9aa6d55932b2: Pull complete
       1b27fd7479e6: Pull complete
       eacdac7d65c9: Pull complete
       66f1bd2ad7cf: Pull complete
       ee6444380c18: Pull complete
       1500f6dd9b69: Pull complete
       18560f19c8c4: Pull complete
       bddc5d1da8e7: Pull complete
       6e33450d197c: Pull complete
       6f195f51537c: Pull complete
       a8c28fabf19a: Pull complete
       ad044e6f6c56: Pull complete
       20144f3a754f: Pull complete
       Digest: sha256:4c3a690b1771ba414c0a347514baae52dae3ec34feb747d5db0c4188d8462562
       Status: Downloaded newer image for nextcloud:latest
       0b3091ea59c416ce8c2dc1fbdbce960ce3c1164e53d2c6fc440222c059abc10a
       root@vps298933:~#


#. Let's verify that it is running using ``docker ps``

   ``docker ps``
       List all **running** containers

   ``docker ps -a``
       List all **running** and **stopped** containers

   .. code-block:: bash
       :caption: Output
       :emphasize-lines: 1

       root@vps298933:~# docker ps
       CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                  NAMES
       f09da32f5217        nextcloud           "/entrypoint.sh apac…"   9 minutes ago       Up 9 minutes        0.0.0.0:20850->80/tcp   hardcore_bhaskara
       root@vps298933:~#


   If you do not see it, then run ``docker ps -a`` to see if it tried to
   start, but then failed. If it did not start correctly, then stop and
   remove it.

   * Steps to stopping and removing a running container:

     #. ``docker stop <Container ID>``
     #. ``docker rm <Container ID>``

#. Let's verify that the application will respond to a web request
   using ``curl``.

   .. code-block:: bash

       curl http://localhost:20850

   .. code-block:: bash
       :caption: Output
       :emphasize-lines: 1

       root@vps298933:~# curl http://localhost:20850
       <!DOCTYPE html>
       <html class="ng-csp" data-placeholder-focus="false" lang="en" data-locale="en" >
               <head data-requesttoken="utvzF1Gkzv92ZJIBFqsjSLd3adMzlGsTqkDz1IHAs2c=:y5GmUDz1/ok0CaBDW8wIcY4lC6Bf5iNg8g6crbeu9VI=">
                       <meta charset="utf-8">
                       <title>
                       Nextcloud               </title>
                       <meta http-equiv="X-UA-Compatible" content="IE=edge">
                       <meta name="referrer" content="no-referrer">
                       <meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0">
                       <meta name="apple-itunes-app" content="app-id=1125420102">
                       <meta name="theme-color" content="#0082c9">
                       <link rel="icon" href="/core/img/favicon.ico">
                       <link rel="apple-touch-icon-precomposed" href="/core/img/favicon-touch.png">
                       <link rel="mask-icon" sizes="any" href="/core/img/favicon-mask.svg" color="#0082c9">
       .
       .
       .

Create a Reverse Proxy for NextCloud
====================================
Repeat the steps that you used for Rocket.Chat to create reverse proxy.

#. Create sub-domain **cloud.example.com**
#. Create your :ref:`nginx-reverse-proxy` using these settings

   * ``server_name cloud.example.com;``
   * ``proxy_pass http://localhost:20850;``

#. Enable the Nginx Site
#. Restart Nginx