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 ```yaml
  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 ```yaml
  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 ```yaml
  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 ```yaml
  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 ```yaml
 103 links:
 104   - link:
 105       name: postgres
 106       alias: postgres
 107 ```
 108
 109 Links another container to the current container. This will add `--link postgres:postgres`
 110 to the options when running the container.
 111
 112 #### environment variables:
 113
 114 Setting environment variables to the current container.
 115
 116 ```yaml
 117 # app.yml
 118
 119 env:
 120   DISCOURSE_DB_HOST: some-host
 121   DISCOURSE_DB_NAME: "{{config}}_discourse"
 122 ```
 123
 124 The above will add `-e DISCOURSE_DB_HOST=some-host -e DISCOURSE_DB_NAME=app_discourse` to the options when running the container.
 125
 126 #### labels:
 127
 128 ```yaml
 129 # app.yml
 130
 131 labels:
 132   monitor: "true"
 133   app_name: "{{config}}_discourse"
 134 ```
 135
 136 Add labels to the current container. The above will add `--l monitor=true -l app_name=dev_discourse` to the options
 137 when running the container
 138
 139 ### Upgrading Discourse
 140
 141 The Docker setup gives you multiple upgrade options:
 142
 143 1. Use the front end at http://yoursite.com/admin/upgrade to upgrade an already running image.
 144
 145 2. Create a new base image manually by running:
 146   - `./launcher rebuild my_image`
 147
 148 ### Single Container vs. Multiple Container
 149
 150 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.
 151
 152 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:
 153
 154 - 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.
 155 - Scale your forum to multiple servers.
 156 - Add servers for redundancy.
 157 - Have some required services (e.g. the database) run on beefier hardware.
 158
 159 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.
 160
 161 WARNING: In a multiple container configuration, *make sure* you setup iptables or some other firewall to protect various ports (for postgres/redis).
 162 On Ubuntu, install the `ufw` or `iptables-persistent` package to manage firewall rules.
 163
 164 ### Email
 165
 166 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.
 167
 168 ### Troubleshooting
 169
 170 View the container logs: `./launcher logs my_container`
 171
 172 Spawn a shell inside your container using `./launcher enter my_container`. This is the most foolproof method if you have host root access.
 173
 174 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.
 175
 176 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:
 177
 178 ```yaml
 179 env:
 180     …existing entries…
 181     HTTP_PROXY: http://proxyserver:port/
 182     http_proxy: http://proxyserver:port/
 183     HTTPS_PROXY: http://proxyserver:port/
 184     https_proxy: http://proxyserver:port/
 185 ```
 186
 187 ### Security
 188
 189 Directory permissions in Linux are UID/GID based, if your numeric IDs on the
 190 host do not match the IDs in the guest, permissions will mismatch. On clean
 191 installs you can ensure they are in sync by looking at `/etc/passwd` and
 192 `/etc/group`, the Discourse account will have UID 1000.
 193
 194
 195 ### Advanced topics
 196
 197 - [Setting up SSL with Discourse Docker](https://meta.discourse.org/t/allowing-ssl-for-your-discourse-docker-setup/13847)
 198 - [Multisite configuration with Docker](https://meta.discourse.org/t/multisite-configuration-with-docker/14084)
 199 - [Linking containers for a multiple container setup](https://meta.discourse.org/t/linking-containers-for-a-multiple-container-setup/20867)
 200 - [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)
 201
 202 License
 203 ===
 204 MIT