13G Filing: Passport Capital and Hortonworks, Inc. (HDP)

Exhibit 1

JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k) under the Securities Exchange
Act of 1934, as amended, the undersigned agree to the joint filing on behalf of
each of them the statement on Schedule 13G to which this agreement is attached
as an exhibit.

The undersigned further agree that each party hereto is
responsible for the timely filing of such Schedule 13G and any amendments
thereto, and for the completeness and accuracy of the information concerning
such party contained therein; provided, however, that no party is responsible
for the completeness or accuracy of the information concerning any other party
making the filing, unless such party knows or has reason to believe that such
information is inaccurate.

IN WITNESS WHEREOF, the parties have executed this Joint Filing
Agreement on March 10, 2016.

The original statement shall be signed by each person on whose
behalf the statement is filed or his authorized representative. If the statement
is signed on behalf of a person by his authorized representative (other than an
executive officer or general partner of this filing person), evidence of the
representative’s authority to sign on behalf of such person shall be filed with
the statement, provided, however, that a power of attorney for this purpose
which is already on file with the Commission may be incorporated by reference.
The name and any title of each person who signs the statement shall be typed or
printed beneath his signature.

Attention:      Intentional
misstatements or omissions of fact constitute Federal criminal violations (See
18 U.S.C. 1001).

Page 7 of 7