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.. Copyright 2015 Comcast Cable Communications Management, LLC
.. 
.. Licensed under the Apache License, Version 2.0 (the "License");
.. you may not use this file except in compliance with the License.
.. You may obtain a copy of the License at
.. 
..     http://www.apache.org/licenses/LICENSE-2.0
.. 
.. Unless required by applicable law or agreed to in writing, software
.. distributed under the License is distributed on an "AS IS" BASIS,
.. WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
.. See the License for the specific language governing permissions and
.. limitations under the License.
.. 

.. _rl-multi-site-origin-qht:

***************************
Configure Multi Site Origin
***************************

1) Create "cachegroups" for the origin locations, and assign the appropriate parent-child relationship between the mid cg's and org cgs (click the image to see full size):

.. image:: C5C4CD22-949A-48FD-8976-C673083E2177.png
	:scale: 100%
	:align: center

2) Create a profile to assign to each of the origins:

.. image:: 19BB6EC1-B6E8-4D22-BFA0-B7D6A9708B42.png
	:scale: 100%
	:align: center

3) Create server entries for the origination vips:

.. image:: D28614AA-9758-45ED-9EFD-3A284FC4218E.png
	:scale: 100%
	:align: center

4) Check the multi-site check box in the delivery service screen and make sure that Content Routing Type is set to HTTP_LIVE_NATL:

.. image:: mso-enable.png
	:scale: 100%
	:align: center

5) Assign the org servers to the delivery service that will have the multi site feature:

.. image:: 066CEF4F-C1A3-4A89-8B52-4F72B0531367.png
	:scale: 100%
	:align: center

.. Note:: “Origin Server Base URL” uniqueness: In order to enable MID caches to distinguish delivery services by different MSO algorithms while performing parent failover, it requires that “Origin Server Base URL” (OFQDN) for each MSO enabled delivery service is unique unless the exceptions listed afterwards. This means that the OFQDN of a MSO enabled delivery service should be different with the OFQDNs of any other delivery service, regardless of whether they are MSO enabled or not. The exceptions are: 
       1) If there are multiple CDNs created on the same Traffic Ops, delivery services across different CDNs may have the same OFQDN configured.
       2) If several delivery services in the same CDN have the same MSO algorithm configured, they may share the same OFQDN.
       3) If delivery services are assigned with different MID cache groups respectively, they can share the same OFQDN.

6) Select an option from the "Multi Site Origin Algorithm" drop-down list. Four MSO algorithms are supported:

+------------------+--------------------------------------------------------------------------------------------------------------------+
|     Option       |                                                            Description                                             |
+==================+====================================================================================================================+
| Consistent hash  | Origin server selection is based on the consistent hash of requested URLs.                                         |
+------------------+--------------------------------------------------------------------------------------------------------------------+
| Primary/back     | Round robin selection does not occur. The first origin server is selected unless it fails.                         |
|                  | If the first fails, the second and other following origin servers will be tried by order.                          |
+------------------+--------------------------------------------------------------------------------------------------------------------+
| Strict           | MID caches serve requests strictly in turn. For example: origin server 1 serves the first request,                 |
| round-robin      | origin server 2 serves the second request, and so on.                                                              |
+------------------+--------------------------------------------------------------------------------------------------------------------+
| IP based         | MID cache goes through the origin server list in a round robin-based on the IP address of EDGE cache.              |
| round-robin      |                                                                                                                    |
+------------------+--------------------------------------------------------------------------------------------------------------------+

7) Optionally, if "Primary/backup" is selected for "Multi Site Origin Algorithm", a new parameter “rank” should be configured for each origin server profile. Origin servers with lower values of rank have higher ranking in the origin server list on MID caches, e.g. OS with rank of "2" precedes OS with the rank of "5". For any OS, if rank value is not defined in its profile, its rank value will default to “1”.

.. image:: mso-rank.png
	:scale: 60%
	:align: center

8) Assign the parent.config location parameter to the MID profile:

.. image:: D22DCAA3-18CC-48F4-965B-5312993F9820.png
	:scale: 100%
	:align: center


9) Configure the mid hdr_rewrite on the delivery service, example: ::

	cond %{REMAP_PSEUDO_HOOK} __RETURN__ set-config proxy.config.http.parent_origin.dead_server_retry_enabled 1 __RETURN__ set-config proxy.config.http.parent_origin.simple_retry_enabled 1 __RETURN__ set-config proxy.config.http.parent_origin.simple_retry_response_codes "400,404,412" __RETURN__ set-config proxy.config.http.parent_origin.dead_server_retry_response_codes "502,503" __RETURN__ set-config proxy.config.http.connect_attempts_timeout 2 __RETURN__ set-config proxy.config.http.connect_attempts_max_retries 2 __RETURN__ set-config proxy.config.http.connect_attempts_max_retries_dead_server 1 __RETURN__ set-config proxy.config.http.transaction_active_timeout_in 5 [L] __RETURN__

10) Turn on parent_proxy_routing in the MID profile.