Setting up Additional CouchDB Instances

While most of the time, it's sufficient to have different applications stored in separate design docs, or in separate DBs, sometimes you just need a separate instance. For example, SSL certificates and port/ip addresses are bound to the erlang instance, not the individual database.

This is the file structure you'll need to create:

• lib/couchdb for the couchdb data files

• {log,run}/couchdb/ are self explanatory

• and a single etc/couchdb/local.ini which will over-ride the system-installed CouchDB default.ini at runtime

    couchdb
    ├── etc
    │   └── couchdb
    │       └── local.ini
    └── var
        ├── lib
        │   └── couchdb
        ├── log
        │   └── couchdb
        └── run
            └── couchdb

• Assuming you adapt OLD & NEW as appropriate, here's how to set it up:

% OLD=/usr/local
% NEW=/tmp/couchdb

% mkdir -p $NEW/etc/couchdb/
% mkdir -p $NEW/var/{lib,log,run}/couchdb/

% cp $OLD/etc/couchdb/local.ini $NEW/etc/couchdb/

% tree -l $NEW
[...tedious output omitted...]

• Don't forget to chown/chmod all these dirs and files so that the future CouchDB user has r/w permissions.

• Finally, you then need to adapt local.ini for these new locations, and obviously include a different port/bind_address combo

[couchdb]
database_dir = /tmp/couchdb/var/lib/couchdb
view_index_dir = /tmp/couchdb/var/lib/couchdb
uri_file = /tmp/couchdb/var/run/couchdb/couch.uri

[httpd]
port = 5985
bind_address = 0.0.0.0

[log]
file = /tmp/couchdb/var/log/couchdb/couch.log

You can test this by running couchdb (in my case interactively using -i):

% couchdb -i -a /tmp/couchdb/etc/couchdb/local.ini

And Relax.

Caveats

The original local.ini is still included in the configuration chain. You can see this by running:

% couchdb -i -a /tmp/couchdb/etc/couchdb/local.ini -c

/usr/local/etc/couchdb/default.ini
/usr/local/etc/couchdb/local.ini
/tmp/couchdb/etc/couchdb/local.ini

This means anything (for example server admins (in [admins] or SSL certificates in [ssl]) that are not over-ridden in your newer config file will apply. If you've got server admins created then don't forget to prune them in the duplicated local.ini if needed.