README.md

   1 ### About
   2
   3 - [Docker](https://docker.com/) is an open source project to pack, ship and run any Linux application in a lighter weight, faster container than a traditional virtual machine.
   4
   5 - Docker makes it much easier to deploy [a Discourse forum](https://github.com/discourse/discourse) on your servers and keep it updated. For background, see [Sam's blog post](http://samsaffron.com/archive/2013/11/07/discourse-in-a-docker-container).
   6
   7 - The templates and base image configure Discourse with the Discourse team's recommended optimal defaults.
   8
   9 ### Getting Started
  10
  11 The simplest way to get started is via the **standalone** template, which can be installed in 30 minutes or less. For detailed install instructions, see
  12
  13 https://github.com/discourse/discourse/blob/master/docs/INSTALL-cloud.md
  14
  15 ### Directory Structure
  16
  17 #### `/cids`
  18
  19 Contains container ids for currently running Docker containers. cids are Docker's "equivalent" of pids. Each container will have a unique git like hash.
  20
  21 #### `/containers`
  22
  23 This directory is for container definitions for your various Discourse containers. You are in charge of this directory, it ships empty.
  24
  25 #### `/samples`
  26
  27 Sample container definitions you may use to bootstrap your environment. You can copy templates from here into the containers directory.
  28
  29 #### `/shared`
  30
  31 Placeholder spot for shared volumes with various Discourse containers. You may elect to store certain persistent information outside of a container, in our case we keep various logfiles and upload directory outside. This allows you to rebuild containers easily without losing important information. Keeping uploads outside of the container allows you to share them between multiple web instances.
  32
  33 #### `/templates`
  34
  35 [pups](https://github.com/samsaffron/pups)-managed templates you may use to bootstrap your environment.
  36
  37 #### `/image`
  38
  39 Dockerfiles for Discourse; see [the README](image/README.md) for further details.
  40
  41 The Docker repository will always contain the latest built version at: https://hub.docker.com/r/discourse/base/, you should not need to build the base image.
  42
  43 ### Launcher
  44
  45 The base directory contains a single bash script which is used to manage containers. You can use it to "bootstrap" a new container, enter, start, stop and destroy a container.
  46
  47 ```
  48 Usage: launcher COMMAND CONFIG [--skip-prereqs]
  49 Commands:
  50     start:      Start/initialize a container
  51     stop:       Stop a running container
  52     restart:    Restart a container
  53     destroy:    Stop and remove a container
  54     enter:      Use docker exec to enter a container
  55     logs:       Docker logs for container
  56         memconfig:  Configure sane defaults for available RAM
  57     bootstrap:  Bootstrap a container for the config based on a template
  58     rebuild:    Rebuild a container (destroy old, bootstrap, start new)
  59 ```
  60
  61 If the environment variable "SUPERVISED" is set to true, the container won't be detached, allowing a process monitoring tool to manage the restart behaviour of the container.
  62
  63 ### Container Configuration
  64
  65 The beginning of the container definition can contain the following "special" sections:
  66
  67 #### templates:
  68
  69 ```
  70 templates:
  71   - "templates/cron.template.yml"
  72   - "templates/postgres.template.yml"
  73 ```
  74
  75 This template is "composed" out of all these child templates, this allows for a very flexible configuration structure. Furthermore you may add specific hooks that extend the templates you reference.
  76
  77 #### expose:
  78
  79 ```
  80 expose:
  81   - "2222:22"
  82   - "127.0.0.1:20080:80"
  83 ```
  84
  85 Publish port 22 inside the container on port 2222 on ALL local host interfaces. In order to bind to only one interface, you may specify the host's IP address as `([<host_interface>:[host_port]])|(<host_port>):<container_port>[/udp]` as defined in the [docker port binding documentation](http://docs.docker.com/userguide/dockerlinks/). To expose a port without publishing it, specify only the port number (e.g., `80`).
  86
  87
  88 #### volumes:
  89
  90 ```
  91 volumes:
  92   - volume:
  93       host: /var/discourse/shared
  94       guest: /shared
  95
  96 ```
  97
  98 Expose a directory inside the host to the container.
  99
 100 #### links:
 101 ```
 102 links:
 103   - link:
 104       name: postgres
 105       alias: postgres
 106 ```
 107
 108 Links another container to the current container. This will add `--link postgres:postgres`
 109 to the options when running the container.
 110
 111 #### environment variables:
 112
 113 Setting environment variables to the current container.
 114
 115 ```
 116 # app.yml
 117
 118 env:
 119   DISCOURSE_DB_HOST: some-host
 120   DISCOURSE_DB_NAME: {{config}}_discourse
 121 ```
 122
 123 The above will add `-e DISCOURSE_DB_HOST=some-host -e DISCOURSE_DB_NAME=app_discourse` to the options when running the container.
 124
 125 #### labels:
 126 ```
 127 # app.yml
 128
 129 labels:
 130   monitor: 'true'
 131   app_name: {{config}}_discourse
 132 ```
 133
 134 Add labels to the current container. The above will add `--l monitor=true -l app_name=dev_discourse` to the options
 135 when running the container
 136
 137 ### Upgrading Discourse
 138
 139 The Docker setup gives you multiple upgrade options:
 140
 141 1. Use the front end at http://yoursite.com/admin/upgrade to upgrade an already running image.
 142
 143 2. Create a new base image manually by running:
 144   - `./launcher rebuild my_image`
 145
 146 ### Single Container vs. Multiple Container
 147
 148 The samples directory contains a standalone template. This template bundles all of the software required to run Discourse into a single container. The advantage is that it is easy.
 149
 150 The multiple container configuration setup is far more flexible and robust, however it is also more complicated to set up. A multiple container setup allows you to:
 151
 152 - Minimize downtime when upgrading to new versions of Discourse. You can bootstrap new web processes while your site is running and only after it is built, switch the new image in.
 153 - Scale your forum to multiple servers.
 154 - Add servers for redundancy.
 155 - Have some required services (e.g. the database) run on beefier hardware.
 156
 157 If you want a multiple container setup, see the `data.yml` and `web_only.yml` templates in the samples directory. To ease this process, `launcher` will inject an env var called `DISCOURSE_HOST_IP` which will be available inside the image.
 158
 159 WARNING: In a multiple container configuration, *make sure* you setup iptables or some other firewall to protect various ports (for postgres/redis).
 160 On Ubuntu, install the `ufw` or `iptables-persistent` package to manage firewall rules.
 161
 162 ### Email
 163
 164 For a Discourse instance to function properly Email must be set up. Use the `SMTP_URL` env var to set your SMTP address, see sample templates for an example. The Docker image does not contain postfix, exim or another MTA, it was omitted because it is very tricky to set up correctly.
 165
 166 ### Troubleshooting
 167
 168 View the container logs: `./launcher logs my_container`
 169
 170 Spawn a shell inside your container using `./launcher enter my_container`. This is the most foolproof method if you have host root access.
 171
 172 If you see network errors trying to retrieve code from `github.com` or `rubygems.org` try again - sometimes there are temporary interruptions and a retry is all it takes.
 173
 174 Behind a proxy network with no direct access to the Internet? Add proxy information to the container environment by adding to the existing `env` block in the `container.yml` file:
 175
 176 ```yaml
 177 env:
 178     …existing entries…
 179     HTTP_PROXY: http://proxyserver:port/
 180     http_proxy: http://proxyserver:port/
 181     HTTPS_PROXY: http://proxyserver:port/
 182     https_proxy: http://proxyserver:port/
 183 ```
 184
 185 ### Security
 186
 187 Directory permissions in Linux are UID/GID based, if your numeric IDs on the
 188 host do not match the IDs in the guest, permissions will mismatch. On clean
 189 installs you can ensure they are in sync by looking at `/etc/passwd` and
 190 `/etc/group`, the Discourse account will have UID 1000.
 191
 192
 193 ### Advanced topics
 194
 195 - [Setting up SSL with Discourse Docker](https://meta.discourse.org/t/allowing-ssl-for-your-discourse-docker-setup/13847)
 196 - [Multisite configuration with Docker](https://meta.discourse.org/t/multisite-configuration-with-docker/14084)
 197 - [Linking containers for a multiple container setup](https://meta.discourse.org/t/linking-containers-for-a-multiple-container-setup/20867)
 198 - [Using Rubygems mirror to improve connection problem in China](https://meta.discourse.org/t/replace-rubygems-org-with-taobao-mirror-to-resolve-network-error-in-china/21988/1)
 199
 200 ### Developing with Vagrant
 201
 202 If you are looking to make modifications to this repository, you can easily test
 203 out your changes before committing, using the magic of
 204 [Vagrant](http://vagrantup.com).  Install Vagrant as per [the default
 205 instructions](http://docs.vagrantup.com/v2/installation/index.html), and
 206 then run:
 207
 208     vagrant up
 209
 210 This will spawn a new Ubuntu VM, install Docker, and then await your
 211 instructions.  You can then SSH into the VM with `vagrant ssh`, become
 212 `root` with `sudo -i`, and then you're right to go.  Your live git repo is
 213 already available at `/vagrant`, so you can just `cd /vagrant`
 214 and then start running `launcher`.
 215
 216
 217 License
 218 ===
 219 MIT