Yet Another Dockerized CouchDB

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  1. 22e2399 Add scripts to simplify creation of multiarch images (#157) by Joan Touzet · 2 days ago master
  2. 00e1ee8 Dockerfile based on the RedHat UBI by Doug Cowie · 8 weeks ago
  3. 6011918 allow running as arbitrary uid (#151) by Will Holley · 3 months ago
  4. d56816f Merge pull request #152 from apache/setuptools by Joan Touzet · 4 months ago
  5. d6cd383 add setuptools to dev images by Will Holley · 4 months ago

Semi-official Apache CouchDB Docker images Build Status

  • Version (stable): CouchDB 2.3.1, Erlang 19.3.5

Available tags

  • latest, 2.3.1: CouchDB 2.3.1 single node (capable of running in a cluster)
  • 2.3.0: CouchDB 2.3.0 single node (capable of running in a cluster)

How to use this image

The most up-to-date instructions on using this image are always available at https://github.com/apache/couchdb-docker/blob/master/README.md .

Start a CouchDB instance

Starting a CouchDB instance is simple:

$ docker run -d --name my-couchdb %%IMAGE%%:tag

where my-couchdb is the name you want to assign to your container, and tag is the tag specifying the CouchDB version you want. See the list above for relevant tags.

Connect to CouchDB from an application in another Docker container

This image exposes the standard CouchDB port 5984, so standard container linking will make it automatically available to the linked containers. Start your application container like this in order to link it to the CouchDB container:

$ docker run --name my-couchdb-app --link my-%%REPO%%:%%REPO%% -d app-that-uses-couchdb

Exposing CouchDB to the outside world

If you want to expose the port to the outside world, run

$ docker run -p 5984:5984 -d %%IMAGE%%

WARNING: Do not do this until you have established an admin user and setup permissions correctly on any databases you have created.

If you intend to network this CouchDB instance with others in a cluster, you will need to map additional ports; see the official CouchDB documentation for details.

Make a cluster

Start your multiple CouchDB instances, then follow the Setup Wizard in the official CouchDB documentation to complete the process.

For a CouchDB cluster you need to provide the NODENAME setting as well as the erlang cookie. Settings to Erlang can be made with the environment variable ERL_FLAGS, e.g. ERL_FLAGS=-setcookie "brumbrum". Further information can be found here.

There is also a Kubernetes helm chart available.

Container shell access, remsh, and viewing logs

The docker exec command allows you to run commands inside a Docker container. The following command line will give you a bash shell inside your %%REPO%% container:

$ docker exec -it my-%%REPO%% bash

If you need direct access to the Erlang runtime:

$ docker exec -it my-%%REPO%% /opt/couchdb/bin/remsh

The CouchDB log is available through Docker's container log:

$ docker logs my-%%REPO%%

Configuring CouchDB

The best way to provide configuration to the %%REPO%% image is to provide a custom ini file to CouchDB, preferably stored in the /opt/couchdb/etc/local.d/ directory. There are many ways to provide this file to the container (via short Dockerfile with FROM + COPY, via Docker Configs, via runtime bind-mount, etc), the details of which are left as an exercise for the reader.

Keep in mind that run-time reconfiguration of CouchDB will overwrite the last file in the configuration chain, and that this Docker container creates the /opt/couchdb/etc/local.d/docker.ini file at startup.

CouchDB also uses /opt/couchdb/etc/vm.args to store Erlang runtime-specific changes. Changing these values is less common. If you need to change the epmd port, for instance, you will want to bind mount this file as well. (Note: files cannot be bind-mounted on Windows hosts.)

In addition, a few environment variables are provided to set very common parameters:

  • COUCHDB_USER and COUCHDB_PASSWORD will create an ini-file based local admin user with the given username and password in the file /opt/couchdb/etc/local.d/docker.ini.
  • COUCHDB_SECRET will set the CouchDB shared cluster secret value, in the file /opt/couchdb/etc/local.d/docker.ini.
  • NODENAME will set the name of the CouchDB node inside the container to couchdb@${NODENAME}, in the file /opt/couchdb/etc/vm.args. This is used for clustering purposes and can be ignored for single-node setups.
  • Erlang Environment Variables like ERL_FLAGS will be used by Erlang itself. For a complete list have a look here

Caveats

Where to Store Data

Important note: There are several ways to store data used by applications that run in Docker containers. We encourage users of the %%REPO%% images to familiarize themselves with the options available, including:

  • Let Docker manage the storage of your database data by writing the database files to disk on the host system using its own internal volume management. This is the default and is easy and fairly transparent to the user. The downside is that the files may be hard to locate for tools and applications that run directly on the host system, i.e. outside containers.
  • Create a data directory on the host system (outside the container) and mount this to a directory visible from inside the container. This places the database files in a known location on the host system, and makes it easy for tools and applications on the host system to access the files. The downside is that the user needs to make sure that the directory exists, and that e.g. directory permissions and other security mechanisms on the host system are set up correctly.

The Docker documentation is a good starting point for understanding the different storage options and variations, and there are multiple blogs and forum postings that discuss and give advice in this area. We will simply show the basic procedure here for the latter option above:

  1. Create a data directory on a suitable volume on your host system, e.g. /home/couchdb/data.
  2. Start your %%REPO%% container like this:
$ docker run --name some-%%REPO%% -v /home/couchdb/data:/opt/couchdb/data -d %%IMAGE%%:tag

The -v /home/couchdb/data:/opt/couchdb/data part of the command mounts the /home/couchdb/data directory from the underlying host system as /opt/couchdb/data inside the container, where CouchDB by default will write its data files.

No system databases until the installation is finalized

Please note that CouchDB no longer autocreates system databases for you, as it is not known at startup time if this is a single-node or clustered CouchDB installation. In a cluster, the databases must only be created once all nodes have been joined together.

If you use the Cluster Setup Wizard or the Cluster Setup API, these databases will be created for you when you complete the process.

If you choose not to use the Cluster Setup wizard or API, you will have to create _global_changes, _replicator and _users manually.

Admin party mode

The node will also start in admin party mode. Be sure to create an admin user! The Cluster Setup Wizard or the Cluster Setup API will do this for you.

You can also use the two environment variables COUCHDB_USER and COUCHDB_PASSWORD to set up an admin user:

$ docker run -e COUCHDB_USER=admin -e COUCHDB_PASSWORD=password -d %%IMAGE%%

Note that if you are setting up a clustered CouchDB, you will want to pre-hash this password and use the identical hashed text across all nodes to ensure sessions work correctly when a load balancer is placed in front of the cluster. Hashing can be accomplished by running the container with the /opt/couchdb/etc/local.d directory mounted as a volume, allowing CouchDB to hash the password you set, then copying out the hashed version and using this value in the future.

Using a persistent CouchDB configuration file

The CouchDB configuration is specified in .ini files in /opt/couchdb/etc. Take a look at the CouchDB configuration documentation to learn more about CouchDB's configuration structure.

If you want to use a customized CouchDB configuration, you can create your configuration file in a directory on the host machine and then mount that directory as /opt/couchdb/etc/local.d inside the %%REPO%% container.

$ docker run --name my-couchdb -v /home/couchdb/etc:/opt/couchdb/etc/local.d -d %%IMAGE%%

The -v /home/couchdb/etc:/opt/couchdb/etc/local.d part of the command mounts the /home/couchdb/etc directory from the underlying host system as /opt/couchdb/etc/local.d inside the container, where CouchDB by default will write its dynamic configuration files.

You can also use couchdb as the base image for your own couchdb instance and provide your own version of the local.ini config file:

Example Dockerfile:

FROM %%IMAGE%%

COPY local.ini /opt/couchdb/etc/

and then build and run

$ docker build -t you/awesome-couchdb .
$ docker run -d -p 5984:5984 you/awesome-couchdb

Remember that, with this approach, any newly written changes will still appear in the /opt/couchdb/etc/local.d directory, so it is still recommended to map this to a host path for persistence.

Logging

By default containers run from this image only log to stdout. You can enable logging to file in the configuration.

For example in local.ini:

[log]
writer = file
file = /opt/couchdb/log/couch.log

It is recommended to then mount this path to a directory on the host, as CouchDB logging can be quite voluminous.

Running under a custom UID

By default, CouchDB will run as the couchdb user with UID 5984. Running under a different UID is supported, so long as any volume mounts have appropriate read/write permissions. For example, assuming user myuser has write access to /home/couchdb/data, the following command will run CouchDB as that user:

docker run --name my-couchdb --user myuser -v /home/couchdb/data:/opt/couchdb/data %%IMAGE%%:tag

Development images

This repository provides definitions to run the very latest (master branch) CouchDB code:

  • dev runs a single node off of the master branch, similar to the other officially released images.
  • dev-cluster demonstrates the CouchDB clustering features by creating a local cluster of a default three nodes inside the container, with a proxy in front. This is great for testing clustering in your local environment.

You will need to build Docker images from the dev directory in this repository; Apache Software Foundation policy prevents us from publishing non-release builds for wide distribution.

When launching the dev-cluster container, here is what you will see:

# expose the cluster to the world
$ docker run -it -p 5984:5984 <image-hash>

[ * ] Setup environment ... ok
[ * ] Ensure CouchDB is built ... ok
[ * ] Prepare configuration files ... ok
[ * ] Start node node1 ... ok
[ * ] Start node node2 ... ok
[ * ] Start node node3 ... ok
[ * ] Check node at http://127.0.0.1:15984/ ... ok
[ * ] Check node at http://127.0.0.1:25984/ ... ok
[ * ] Check node at http://127.0.0.1:35984/ ... ok
[ * ] Running cluster setup ... ok
[ * ] Developers cluster is set up at http://127.0.0.1:15984.
Admin username: root
Password: 37l7YDQJ
Time to hack! ...

Note: By default the cluster will be exposed on port 5984, because it uses haproxy (passes --with-haproxy to dev/run) internally.

You can pass arguments to the binary:

docker run -it <image-hash> --admin=foo:bar

Note: This will overwrite the default --with-haproxy flag. The cluster won't be exposed on port 5984 anymore. The individual nodes listen on 15984, 25984, ...x5984. If you wish to expose the cluster on 5984, pass --with-haproxy explicitly.

More examples:

# display the available options of the couchdb startup script
docker run --rm <image-hash> --help

# Enable admin party and expose the cluster on port 5984
docker run -it -p 5984:5984 <image-hash> --with-admin-party-please --with-haproxy

# Start two nodes (without proxy) exposed on port 15984 and 25984
docker run -it -p 15984:15984 -p 25984:25984 <image-hash> -n 2

Image building for CouchDB release managers

Check out the build.sh script in the apache/couchdb-docker GitHub repository, which can build images for any version, even in a cross-platform way.

Also, read the next section to ensure you push all of the tags necessary.

Image uploading for CouchDB release managers

Taking a hypothetical example of CouchDB 2.9.7, here‘s all of the tags you’d want:

docker build -t apache/couchdb:2.9.7 2.9.7
docker tag apache/couchdb:2.9.7 apache/couchdb:latest
docker tag apache/couchdb:2.9.7 apache/couchdb:2.9
docker tag apache/couchdb:2.9.7 apache/couchdb:2
docker login
docker push apache/couchdb:2.9.7
docker push apache/couchdb:2.9
docker push apache/couchdb:2
docker push apache/couchdb:latest

Obviously don't create/push the latest or 2 tags if this is a maintenance branch superceded by a newer one.

The build.sh utility can help you do this quickly, see its usage help for more details.

Feedback, Issues, Contributing

General feedback is welcome at our user or developer mailing lists.

Apache CouchDB has a CONTRIBUTING file with details on how to get started with issue reporting or contributing to the upkeep of this project. In short, use GitHub Issues, do not report anything on Docker's website.

Non-Apache CouchDB Development Team Contributors