Cooperative fault tolerance and load balancing
View Patent ↗Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for cooperative fault tolerance and load balancing. In one aspect, a method includes receiving a request from an entity wherein the request includes metadata specifying a plurality of non-responsive servers to which the entity sent the request but that could not process the request; determining that the data processing apparatus is not a current home server for the entity based on information cached in the data processing apparatus, wherein the current home server is a server within a plurality of preferred servers that processes requests for the entity and, in response thereto: assigning the data processing apparatus as the current home server so that the entity will send subsequent requests to the data processing apparatus for processing; and sending a response to the entity.
1. A method implemented at a client device, comprising:
creating, at a client, requests on behalf of an entity;
for each request:
accessing, at the client, a homing cache storing an assignment list for the entity that specifies one or more servers for the entity;
determining, from the assignment list, the entity's current home server;
sending the request to the current home server; and
determining whether there is failure of the current home server for the request;
for each request for which there is a determined failure of the current home server:
selecting, from the assignment list, a next listed server as the current home server for the entity;
attaching, to the request, metadata describing the prior current home server as a failed server; and
sending the request with the attached metadata to the current home server.
2. The method of claim 1 , further comprising updating metadata stored at the user device that describes a list of failed server to include the prior current home server.
3. The method of claim 2 , further comprising, for each request for which there is not a determined failure of the current home server:
receiving a response from the current home server;
if the response is not a redirect, updating a homing cache in the user device; and
if the response is a redirect, adding, at the user device, the current home server to a list of re-directing servers.
4. The method of claim 3 , further comprising, if the response is a redirect, sending the request to the server specified by the redirect.
5. A client device, comprising:
a hardware processor; and
a non-transitory computer-readable medium coupled to the processor and having instructions stored thereon, which, when executed by the processor, cause the processor to perform operations comprising:
creating, at a client, requests on behalf of an entity;
for each request:
accessing, at the client, a homing cache storing an assignment list for the entity that specifies one or more servers for the entity;
determining, from the assignment list, the entity's current home server;
sending the request to the current home server; and
determining whether there is failure of the current home server for the request;
for each request for which there is a determined failure of the current home server:
selecting, from the assignment list, a next listed server as the current home server for the entity;
attaching, to the request, metadata describing the prior current home server as a failed server; and
sending the request with the attached metadata to the current home server.
6. The client device of claim 5 , the operations further comprising updating metadata stored at the user device that describes a list of failed server to include the prior current home server.
7. The client device of claim 6 , the operations further comprising, for each request for which there is not a determined failure of the current home server:
receiving a response from the current home server;
if the response is not a redirect, updating a homing cache in the user device; and
if the response is a redirect, adding, at the user device, the current home server to a list of re-directing servers.
8. The client device of claim 7 , the operations further comprising, if the response is a redirect, sending the request to the server specified by the redirect.
9. A non-transitory computer-readable medium having instructions stored thereon, which, when executed by a processor in a server, cause the processor to perform operations comprising:
creating, at a client, requests on behalf of an entity;
for each request:
accessing, at the client, a homing cache storing an assignment list for the entity that specifies one or more servers for the entity;
determining, from the assignment list, the entity's current home server;
sending the request to the current home server; and
determining whether there is failure of the current home server for the request;
for each request for which there is a determined failure of the current home server:
selecting, from the assignment list, a next listed server as the current home server for the entity;
attaching, to the request, metadata describing the prior current home server as a failed server; and
sending the request with the attached metadata to the current home server.
10. The non-transitory computer-readable medium of claim 9 , the operations further comprising updating metadata stored at the user device that describes a list of failed server to include the prior current home server.
11. The non-transitory computer-readable medium of claim 10 , the operations further comprising, for each request for which there is not a determined failure of the current home server:
receiving a response from the current home server;
if the response is not a redirect, updating a homing cache in the user device; and
if the response is a redirect, adding, at the user device, the current home server to a list of re-directing servers.
12. The non-transitory computer-readable medium of claim 11 , the operations further comprising, if the response is a redirect, sending the request to the server specified by the redirect.