Exhibit 10.5(b)
JOINDER AGREEMENT
THIS JOINDER AGREEMENT (“Joinder Agreement”) is executed as of October 2, 2018,
by C1-Allen LLC, a Delaware limited liability company, C1-ATL LLC, a Delaware
limited liability company, C1-Mesa LLC, Delaware limited liability company,
C1-Sterling VIII LLC, a Delaware limited liability company, C1-Santa Clara LLC,
a Delaware limited liability company, Warhol TRS LLC, a Delaware limited
liability company, Warhol Partnership LLC, a Delaware limited liability company,
and Warhol REIT LLC, a Delaware limited liability company (each, a “Joining
Party” and collectively, the “Joining Parties”)), and delivered to JPMorgan
Chase Bank, N.A., as Administrative Agent, pursuant to Section 2.24 of the
Credit Agreement dated as of March 29, 2018, as amended, restated or otherwise
modified from time to time (the “Credit Agreement”), among CyrusOne LP (the
“Company”), the Subsidiary Borrowers party thereto, the Lenders and agents party
thereto, and JPMorgan Chase Bank, N.A., as Administrative Agent. Terms used but
not defined in this Joinder Agreement shall have the meanings defined for those
terms in the Credit Agreement.
RECITALS
A.    Each Joining Party wishes, in accordance with Section 2.24 of the Credit
Agreement, to become an additional Subsidiary Guarantor under the Guarantee
Agreement.
B.    Each Joining Party expects to realize direct and indirect benefits as a
result of the availability to the Borrowers of the credit facilities under the
Credit Agreement.
NOW, THEREFORE, each Joining Party agrees as follows:
AGREEMENT
1.    Joinder. By this Joinder Agreement, each Joining Party hereby becomes a
“Subsidiary Guarantor” and a “Guarantor” under the Guarantee Agreement, and the
other Loan Documents with respect to all the Obligations of the Borrowers now or
hereafter incurred under the Credit Agreement and the other Loan Documents. Each
Joining Party agrees that, as of the Effective Date (and, in the case of
representations and warranties, subject to the following paragraph) such Joining
Party is and shall be bound by, and hereby assumes, all representations,
warranties, covenants, terms, conditions, duties and waivers applicable to a
Subsidiary Guarantor and a Guarantor under the Guarantee Agreement and the other
Loan Documents.
2.    Representations and Warranties of the Joining Parties. Each Joining Party
represents and warrants to Administrative Agent that, as of the Effective Date
(as defined below), except as disclosed in writing by such Joining Party to
Administrative Agent on or prior to the date hereof and approved by the
Administrative Agent in writing (which disclosures shall be deemed to amend the
Schedules and other disclosures delivered as contemplated in the Credit
Agreement and which disclosures are attached hereto as Schedule A), the
representations and warranties contained in the Credit Agreement and the other
Loan Documents are true and correct in all material respects as applied to such
Joining Party as a Subsidiary Guarantor and a Guarantor on and as of the
Effective Date as though made on that date (unless such representations apply to
any earlier date). As of the Effective Date, each Joining Party shall be in
compliance with all covenants and agreements in the Loan Documents of a
Subsidiary Guarantor with respect to such Joining Party and no Default or Event
of Default exists or will exist after giving effect hereto as of the date
hereof.

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3.    Joint and Several. Each Joining Party hereby agrees that, as of the
Effective Date, the Guarantee Agreement and the other Loan Documents heretofore
delivered to Administrative Agent and the Lenders shall be a joint and several
obligation of such Joining Party to the same extent as if executed and delivered
by such Joining Party, and upon request by Administrative Agent, will promptly
become a party to the Guarantee Agreement and the other applicable Loan
Documents to confirm such obligation.
4.    Further Assurances. Each Joining Party agrees to execute and deliver such
other instruments and documents and take such other action, as Administrative
Agent may reasonably request, in connection with the transactions contemplated
by this Joinder Agreement.
5.    GOVERNING LAW. THIS AGREEMENT SHALL BE DEEMED TO BE A CONTRACTUAL
OBLIGATION UNDER, AND SHALL, PURSUANT TO NEW YORK GENERAL OBLIGATIONS LAW
SECTION 5-1401, BE GOVERNED BY AND CONSTRUED AND ENFORCED IN ACCORDANCE WITH,
THE LAWS OF THE STATE OF NEW YORK.
6.    Counterparts. This Agreement may be executed in any number of counterparts
which shall together constitute but one and the same agreement.
7.    The effective date (the “Effective Date”) of this Joinder Agreement shall
be the date first above written.
IN WITNESS WHEREOF, each Joining Party has executed this Joinder Agreement under
seal as of the day and year first above written.
“JOINING PARTIES”:
C1-ALLEN LLC, a Delaware limited liability company
By: /s/ Diane M. Morefield    
Name: Diane M. Morefield    
Title: Chief Financial Officer    
(SEAL)
C1-ATL LLC, a Delaware limited liability company
By: /s/ Diane M. Morefield    
Name: Diane M. Morefield    
Title: Chief Financial Officer    
(SEAL)
C1-MESA LLC, a Delaware limited liability company
By: /s/ Diane M. Morefield    
Name: Diane M. Morefield    
Title: Chief Financial Officer    
(SEAL)

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C1-STERLING VIII LLC, a Delaware limited liability company
By: /s/ Diane M. Morefield    
Name: Diane M. Morefield    
Title: Chief Financial Officer    
(SEAL)
C1-SANTA CLARA LLC, a Delaware limited liability company
By: /s/ Diane M. Morefield    
Name: Diane M. Morefield    
Title: Chief Financial Officer    
(SEAL)
WARHOL TRS LLC, a Delaware limited liability company
By: /s/ Diane M. Morefield    
Name: Diane M. Morefield    
Title: Chief Financial Officer    
(SEAL)
WARHOL PARTNERSHIP LLC, a Delaware limited liability company
By: /s/ Diane M. Morefield    
Name: Diane M. Morefield    
Title: Chief Financial Officer    
(SEAL)
WARHOL REIT LLC, a Delaware limited liability company
By: /s/ Diane M. Morefield    
Name: Diane M. Morefield    
Title: Chief Financial Officer    
(SEAL)

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ACKNOWLEDGED:
JPMORGAN CHASE BANK, N.A., as Administrative Agent
By: /s/Alexander Vardama
Its: Vice President
Title: Authorized Signer