The path for the index files can be configured through the use of the index_path parameter:

Example as follows:

shell> curl -X POST -u admin:password \
    -d index_path=/var/tmp/text-index \
    http://localhost:8091/nodes/self/controller/settings

As a raw HTTP request:

POST /nodes/self/controller/settings HTTP/1.1
Host: localhost:8091
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
Authorization: Basic YWRtaW46YWRtaW4=
Content-Length: xx path=/var/tmp/test

The HTTP response will contain the response code and optional error message:

HTTP/1.1 200 OK
Content-Type: application/json
Content-Length: 0

As of Couchbase Server 2.0.1 if you try to set the data path at this endpoint, you will receive this error:

ERROR: unable to init 10.3.4.23 (400) Bad Request
{u'error': u'Changing data of nodes that are part of provisioned cluster is not supported'}