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Posted to dev@trafficcontrol.apache.org by "John Shen (weifensh)" <we...@cisco.com> on 2018/04/02 11:43:05 UTC

Traffic Control Last-resort Routing

Hi guys,

We are planning to add a Last-resort routing feature to Traffic Control. It will make TR redirect a request to an alternate domain, an error domain, or an origin server when there is not suitable cache available (e.g. all caches are busy). It is similar with current “Bypass FQDN” in TC, but it adds more parameters like redirecting to error domains or origin servers.

All the new parameters will be configured through “DS Profile” (to avoid GUI and DB schema changes), which is different with the current GUI configuration of “Bypass FQDN”. So the design will not change the current “Bypass FQDN” feature, and just add Last-resort as another extra feature. If Last-resort feature is not enabled (by default), the current behavior of Traffic Router will not change.

Please refer to following doc for more details: https://docs.google.com/document/d/1ttrZUGoGZTdCT6g78v62xBVoDCC_cWesPzxfLaHBcp0/edit

Any comments are welcome.

Thanks,
John

Re: Traffic Control Last-resort Routing

Posted by "Eric Friedrich (efriedri)" <ef...@cisco.com>.
Sounds good John. 

If you can provide a path, we shouldn’t call it Error Domain :-) We should call it “Error Redirect URL”.

—Eric

> On Apr 3, 2018, at 11:02 PM, John Shen (weifensh) <we...@cisco.com> wrote:
> 
> Hey Eric,
> 
> Thanks a lot for your comments. Please refer to my reply inline.
> 
> Thanks,
> John
> 
> 
> On 2018/4/3, 8:36 PM, "Eric Friedrich (efriedri)" <ef...@cisco.com> wrote:
> 
>    Hey John-
>    1)“Last Resort Alternate domain” is incredibly similar to the Bypass FQDN. I’d rather see us enhance the Bypass FQDN with an optional scheme and port number, rather than add something so close in functionality. 
>    [John] Yeah, we had the same thought. The only disadvantage is that we are planning to use "DS Profile" instead of changing the GUI and DB schema to support the new parameters, thus we will have the new options (e.g. scheme and port) configured by "DS profile" and Bypass FQDN configured through GUI for each DS. If no one has objection with this mixed configuration solution, we would implement the Alternate domain/Bypass FQDN in this way.
> 
>    2) Is there a definite need for the “To content origin” checkbox? If this is only used when Bypass FQDN/Alternate domain is not configured, then we could just ask the user to configure the Origin FQDN in this field. 
>    [John] Yes, “To content origin” is only used when alternate domain is not configured. Asking user to configure OFQDN in the alternate domain would make the implementation easier. It's just that a user has to manually fill the field.
> 
>    3) Alternate Domain and Error domain also seem incredibly similar in the proposal. Would error domain be better described as “Redirect location for unknown delivery service FQDNs or blocked clients. If not set, TR would typically return a 503” 
>    [John] One difference is that for Error domain, user can configure a file to redirect to, e.g. to "http://error-domain.org/404.html". Error domain (with filename) is the redirect location when there is no available cache in a DS.
> 
>    —Eric
> 
>> On Apr 2, 2018, at 7:43 AM, John Shen (weifensh) <we...@cisco.com> wrote:
>> 
>> Hi guys,
>> 
>> We are planning to add a Last-resort routing feature to Traffic Control. It will make TR redirect a request to an alternate domain, an error domain, or an origin server when there is not suitable cache available (e.g. all caches are busy). It is similar with current “Bypass FQDN” in TC, but it adds more parameters like redirecting to error domains or origin servers.
>> 
>> All the new parameters will be configured through “DS Profile” (to avoid GUI and DB schema changes), which is different with the current GUI configuration of “Bypass FQDN”. So the design will not change the current “Bypass FQDN” feature, and just add Last-resort as another extra feature. If Last-resort feature is not enabled (by default), the current behavior of Traffic Router will not change.
>> 
>> Please refer to following doc for more details: https://docs.google.com/document/d/1ttrZUGoGZTdCT6g78v62xBVoDCC_cWesPzxfLaHBcp0/edit
>> 
>> Any comments are welcome.
>> 
>> Thanks,
>> John
>> 
> 
> 
>

Re: Traffic Control Last-resort Routing

Posted by "John Shen (weifensh)" <we...@cisco.com>.
Hey Eric,

Thanks a lot for your comments. Please refer to my reply inline.
 
Thanks,
John

 
On 2018/4/3, 8:36 PM, "Eric Friedrich (efriedri)" <ef...@cisco.com> wrote:

    Hey John-
    1)“Last Resort Alternate domain” is incredibly similar to the Bypass FQDN. I’d rather see us enhance the Bypass FQDN with an optional scheme and port number, rather than add something so close in functionality. 
    [John] Yeah, we had the same thought. The only disadvantage is that we are planning to use "DS Profile" instead of changing the GUI and DB schema to support the new parameters, thus we will have the new options (e.g. scheme and port) configured by "DS profile" and Bypass FQDN configured through GUI for each DS. If no one has objection with this mixed configuration solution, we would implement the Alternate domain/Bypass FQDN in this way.

    2) Is there a definite need for the “To content origin” checkbox? If this is only used when Bypass FQDN/Alternate domain is not configured, then we could just ask the user to configure the Origin FQDN in this field. 
    [John] Yes, “To content origin” is only used when alternate domain is not configured. Asking user to configure OFQDN in the alternate domain would make the implementation easier. It's just that a user has to manually fill the field.

    3) Alternate Domain and Error domain also seem incredibly similar in the proposal. Would error domain be better described as “Redirect location for unknown delivery service FQDNs or blocked clients. If not set, TR would typically return a 503” 
    [John] One difference is that for Error domain, user can configure a file to redirect to, e.g. to "http://error-domain.org/404.html". Error domain (with filename) is the redirect location when there is no available cache in a DS.

    —Eric
    
    > On Apr 2, 2018, at 7:43 AM, John Shen (weifensh) <we...@cisco.com> wrote:
    > 
    > Hi guys,
    > 
    > We are planning to add a Last-resort routing feature to Traffic Control. It will make TR redirect a request to an alternate domain, an error domain, or an origin server when there is not suitable cache available (e.g. all caches are busy). It is similar with current “Bypass FQDN” in TC, but it adds more parameters like redirecting to error domains or origin servers.
    > 
    > All the new parameters will be configured through “DS Profile” (to avoid GUI and DB schema changes), which is different with the current GUI configuration of “Bypass FQDN”. So the design will not change the current “Bypass FQDN” feature, and just add Last-resort as another extra feature. If Last-resort feature is not enabled (by default), the current behavior of Traffic Router will not change.
    > 
    > Please refer to following doc for more details: https://docs.google.com/document/d/1ttrZUGoGZTdCT6g78v62xBVoDCC_cWesPzxfLaHBcp0/edit
    > 
    > Any comments are welcome.
    > 
    > Thanks,
    > John
    >

Re: Traffic Control Last-resort Routing

Posted by "Eric Friedrich (efriedri)" <ef...@cisco.com>.
Hey John-
1)“Last Resort Alternate domain” is incredibly similar to the Bypass FQDN. I’d rather see us enhance the Bypass FQDN with an optional scheme and port number, rather than add something so close in functionality. 

2) Is there a definite need for the “To content origin” checkbox? If this is only used when Bypass FQDN/Alternate domain is not configured, then we could just ask the user to configure the Origin FQDN in this field. 

3) Alternate Domain and Error domain also seem incredibly similar in the proposal. Would error domain be better described as “Redirect location for unknown delivery service FQDNs or blocked clients. If not set, TR would typically return a 503” 

—Eric

> On Apr 2, 2018, at 7:43 AM, John Shen (weifensh) <we...@cisco.com> wrote:
> 
> Hi guys,
> 
> We are planning to add a Last-resort routing feature to Traffic Control. It will make TR redirect a request to an alternate domain, an error domain, or an origin server when there is not suitable cache available (e.g. all caches are busy). It is similar with current “Bypass FQDN” in TC, but it adds more parameters like redirecting to error domains or origin servers.
> 
> All the new parameters will be configured through “DS Profile” (to avoid GUI and DB schema changes), which is different with the current GUI configuration of “Bypass FQDN”. So the design will not change the current “Bypass FQDN” feature, and just add Last-resort as another extra feature. If Last-resort feature is not enabled (by default), the current behavior of Traffic Router will not change.
> 
> Please refer to following doc for more details: https://docs.google.com/document/d/1ttrZUGoGZTdCT6g78v62xBVoDCC_cWesPzxfLaHBcp0/edit
> 
> Any comments are welcome.
> 
> Thanks,
> John
>