ckan-docker

Developing and deploying CKAN with Docker

Intro

Dockerfiles, Docker-compose service definition & Vagrantfile to develop & deploy CKAN, Postgres, Solr & datapusher using Docker.

Docker containers included:

• CKAN (should work with any version 2.x)
• Postgres (Postgres 9.3 and PostGIS 2.1, CKAN datastore & spatial extension supported)
• Solr (4.10.1, custom schemas & spatial extension supported)
• Docker-compose [optional] (to manage the containers)
• Data [optional] (to store Postgres data & CKAN FileStore separately)

Other contrib containers:

• Nginx (1.7.6 official) as a caching reverse proxy
• Datapusher

Requirements

Name	Version	Comment
Docker	>= 1.3	works with Boot2docker 1.3
Docker-compose	>= 1.1.0	on the host or with Dockerfile provided
Vagrant	>= 1.6	if you intend to use Vagrant
OS	any	as long as you can run Docker 1.3

Reference

Structure

├── Dockerfile (CKAN Dockerfile)
├── README.md
├── Vagrantfile (CKAN Vagrantfile)
├── _etc (config copied to /etc)
│   ├── apache2
│   ├── ckan
│   ├── cron.d
│   ├── my_init.d
│   ├── postfix
│   └── supervisor
├── _service-provider (any service provider such as datapusher)
│   └── datapusher
├── _solr
│   └── schema.xml (version specific & custom schema)
├── _src (CKAN source code & extensions)
│   ├── ckan
│   └── ckanext-...
├── docker
│   ├── ckan
│   ├── data
│   ├── compose
│   ├── nginx
│   ├── insecure_key (baseimage insecure SSH key)
│   ├── postgres
│   └── solr
├── docker-compose.yml (CKAN services definition)
└── vagrant
    └── docker-host (Linux Docker host if required)

Directories

the content from the directories prefixed with _ need to be edited / configured as required before building the Dockerfiles.

_etc

contains configuration files that are copied to /etc in the container. see _etc/README

_solr

contains your custom Solr schema (for your version of CKAN, & extensions installed). see _solr/README

_src

contains your packages source code (CKAN & extensions). see _src/README

_service-provider

contains any service providers (e.g. datapusher) with their Dockerfiles. see _service-provider/README.

docker

contains the Dockerfiles and any supporting files

vagrant

contains the Docker host if the host cannot run Docker containers natively (OS X & Windows)

Files

Dockerfiles

The Dockerfiles are currently based on phusion/baseimage:0.9.16.

SSH is supported using an insecure key which is enabled by default for development purposes. You should disable it in production use for obvious reasons.

Read this to find out more about phusion baseimage

CKAN Dockerfile

The app container runs the following services

• Apache
• Postfix
• Supervisor
• Cron

Postgres Dockerfile

The database container runs Postgres 9.3 and PostGIS 2.1. It supports the datastore & ckanext-spatial

Data Dockerfile

The data container is optional but recommended. It exposes two volumes to store the Postgres data ($PGDATA) & CKAN FileStore. This means you can recreate / app containers without losing your data.

Solr Dockerfile

The Solr container runs version 4.10.1. This can easily be changed by customising SOLR_VERSION in the Dockerfile.

By detault the schema.xml of the upstream version (2.3) is copied in the container. This can be overriden at runtime by mounting it as a volume. This default path of the volume is <path to>/_src/ckan/ckan/config/solr/schema.xml so it mounts the schema corresponding to your version of CKAN.

For example for Docker-compose:

solr:
  build: docker/solr
  hostname: solr
  domainname: localdomain
  ports:
    - "8983:8983"
  volumes:
    - <path to>/_src/ckan/ckan/config/solr/schema.xml:/opt/solr/example/solr/ckan/conf/schema.xml

If you need a custom schema, put it in <full path to>/_solr and change the path in the docker-compose or vagrant file.

  volumes:
    - <path to>/_solr/schema.xml:/opt/solr/example/solr/ckan/conf/schema.xml

The container is cross version compatible. You need mount the appropriate schema.xml as a volume, or build a child image, which will copy the schema.xml next to your Dockerfile.

Read the ckanext-spatial documentation to add the required fields to your Solr schema if you use ckanext-spatial

Docker-compose Dockerfile

The Docker-compose container runs the latests Docker-compose & Docker within a container.

The Docker socket needs to be mounted as a volume to control Docker on the host. A source folder must be mounted to access the docker-compose definition

see docker/compose/Readme to find out how to use

Vagrantfile

Defines VMs provided by Docker, a Virtual Box docker-host is used if the host can't run Docker containers natively. This is an alternative to Boot2Docker.

docker-compose.yml

Defines the set of services required to run CKAN. Read the docker-compose.yml reference to understand and edit.

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Usage

1. Clone your code in the _src directory (see _src/README)
2. Clone the datapusher in _service-provider (see _service-provider/README)
3. Set the full path of the volumes in docker-compose.yml
4. Run up with Docker-compose or Vagrant

Using Docker-compose (recommended)

Option 1: Docker-compose is installed on the Docker host

If you have it installed, just type

docker-compose up

Option 2: Using the docker-compose container

Otherwise, you can use the container provided

Build the Docker-compose container

docker build --tag="dockercompose_container" docker/compose

Run it

docker run -it -d --name="dockercompose-ckan" -p 2375 -v /var/run/docker.sock:/tmp/docker.sock -v $(pwd):/src dockercompose_container

In the Docker-compose container docker-compose won't work with relative path, because the mount namespace is different, you need to change the relative path to absolute path

for example, change the ./:

volumes:
    - ./_src:/usr/lib/ckan/default/src

to an absolute path to you ckan-docker directory: /Users/username/git/ckan/ckan-docker/

volumes:
    - /Users/username/git/ckan/ckan-docker/_src:/usr/lib/ckan/default/src

Build & Run the services defined in docker-compose.yml

docker exec -it dockercompose-ckan docker-compose up

If you are using boot2docker, add entries in your hosts file e.g. 192.168.59.103 ckan.localdomain

You can now access CKAN at http://ckan.localdomain:8080/ (Apache) & http://ckan.localdomain/ (Ngnix)

Using Vagrant

Build & run

vagrant up --provider=docker --no-parallel

You can now access CKAN at http://localhost:8080/ (Apache)

You can also SSH inside the container if you have left the --enable-insecure-key option in the run command.

vagrant ssh ckan

SSH insecure key can be disabled by removing the --enable-insecure-key option from the run command.

---

Running commands inside the container

The simplest thing to do is to use the docker exec command, for example:

docker exec -it src_ckan_1 /bin/bash

You can also SSH inside the container if you have left the --enable-insecure-key option in the run command.

ssh -i docker/insecure_key -p 2222 root@ckan.localdomain

SSH insecure key can be disabled by removing the --enable-insecure-key option from the run command.

Managing Docker images & containers

You should use docker-compose to manage your containers & images, this will ensure they are started/stopped in order

If you want to quickly remove all untagged images:

docker images -q --filter "dangling=true" | xargs docker rmi

If you want to quickly remove all stopped containers

docker rm $(docker ps -a -q)

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Developing CKAN

Using paster serve instead of apache for development

CKAN container starts Apache2 by default and the ckan.site_url port is set to 8080 in 50_configure. You can override that permanently in the custom_options.ini, or manually in the container, for instance if you want to use paster in a development context.

Example (paster serve --reload in debug mode):

docker exec -it src_ckan_1 /bin/bash
supervisorctl stop apache2
sed -i -r 's/debug = false/debug = true/' $CKAN_CONFIG/$CONFIG_FILE
sed -i -r 's/ckan.localdomain:8080/ckan.localdomain:5000/' $CKAN_CONFIG/$CONFIG_FILE
$CKAN_HOME/bin/paster serve --reload $CKAN_CONFIG/$CONFIG_FILE

Frontend development

Front end development is also possible (see Frontend development guidelines)

Install frontend dependencies:

docker exec -it src_ckan_1 /bin/bash
apt-get update
apt-get install -y nodejs npm
ln -s /usr/bin/nodejs /usr/bin/node
source $CKAN_HOME/bin/activate
cd $CKAN_HOME/
npm install nodewatch less@1.3.3

Both examples show that development dependencies should only be installed in the containers when required. Since they are not part of the Dockerfile they do not persist and only serve the purpose of development. When they are no longuer needed the container can be rebuilt allowing to test the application in a production-like state.

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Sources

• Docker
• Docker-compose
• Vagrant Docker provider