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# CouchDB

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From ArchWiki

"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}

## See also

- Official CouchDB page
- CouchDB Document
- CouchDB - The Definitive Guide
- create a read-only database

Category:

- Database management systems