CouchDB

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"Apache CouchDB is a document-oriented database that can be queried and indexed in a MapReduce fashion using JavaScript." ― CouchDB homepage

Installation

Install the couchdb package.

Usage

Before you start the application, you need to create admin account as follows [1]:

/etc/couchdb/local.ini

[admins]
admin = plain-password

After starting CouchDB for the first time, plain-password will be replaced with the hashed version.

Next, start/enable the couchdb.service daemon.

Test to see if the service is running by running curl http://127.0.0.1:5984/. Note that in order to access this instance of CouchDB from another system, you will need to configure it (see below).

Using Fauxton admin interface

You can now access the Fauxton admin interface by going to http://localhost:5984/_utils.

Configuration

You can do this through Fauxton or using command line.

To setup the database and create an admin account through Fauxton, visit http://127.0.0.1:5984/_utils/#setup.

To setup a single node from the command line (where <adminuser> and <password> are to be replaced).

$ curl -X POST -H "Content-Type: application/json" http://127.0.0.1:5984/_cluster_setup -d '{"action": "enable_single_node", "bind_address":"127.0.0.1", "username": "<adminuser>", "password": "<password>"}'

Also, you might want to take a look at #Single node setup & Security.

Tip: If you are doing a cluster setup, you might want to set bind_address to 0.0.0.0 to access CouchDB from other nodes.

Note that you can also do all this as well as changing the default port, bind address, log-level and other useful nuggets in /etc/couchdb/local.ini.

Note: Do not modify /etc/couchdb/default.ini as it gets overwritten whenever couchdb is updated, copy any values you would like to change and put them in /etc/couchdb/local.ini. Also be sure to restart couchdb.service after changes to this file.

If you want to run CouchDB on port 80 you will have to run the daemon as root, use a reverse proxy or set an iptables rule such as:

$ iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-ports 5984

Creating a self-signed certificate

If you would like to use ssl with a self-signed certificate you can create one like this:

# cd /etc/couchdb
# openssl req -new -x509 -nodes -newkey rsa:4096 -keyout server.key -out server.crt

Then uncomment httpsd and update the paths in [daemons] and [ssl] sections:

/etc/couchdb/local.ini

[daemons]
httpsd = {couch_httpd, start_link, [https]}

[ssl]
cert_file = /etc/couchdb/server.crt
key_file = /etc/couchdb/server.key

Fauxton can then be accessed over SSL on port 6984 via https://localhost:6984/_utils/.

Single node setup & Security

If you run CouchDB in a single node setup, you might want to increase security by not binding unnecessarily on public network interfaces. Two process are actually doing so: epmd and beam.smp. The first one is quite easy to work around, you can simply add the following systemd drop-in addition to couchdb.service:

/etc/systemd/system/couchdb.service.d/10-bind-locally.conf

[Service]
Environment=ERL_EPMD_ADDRESS=127.0.0.1

The second one needs an edit in vm.args

/etc/couchdb/vm.args

-kernel inet_dist_use_interface {127,0,0,1}