Nick, if you're open to writing code, it wouldn't be overly difficult to modify the parent_select plugin to do what you want.
https://github.com/apache/trafficserver/tree/master/plugins/experimental/parent_select https://docs.trafficserver.apache.org/en/latest/admin-guide/plugins/parent_select.en.html https://docs.trafficserver.apache.org/en/latest/admin-guide/files/strategies.yaml.en.html On Thu, Sep 15, 2022 at 1:55 PM Nick Dunkin <nick.dun...@vecima.com.invalid> wrote: > Hi John, > > Thanks. > > But if I have 5 primary parents in “cluster A”, and 3 secondary parents in > “cluster B”, then there is no configuration that will get me to “cluster B’ > if the content is not available (404) on “cluster A”. Which is my problem > unfortunately. > > > I’d like to push that value of > > > > #define MAX_SIMPLE_RETRIES 5 > > in the code, and rebuild. Any reason that won’t work until I can create a > more robust solution? > > Thanks, > > Nick > > From: John Rushford <jjrushf...@gmail.com> > Date: Thursday, September 15, 2022 at 3:40 PM > To: dev@trafficserver.apache.org <dev@trafficserver.apache.org> > Subject: Re: Different parent rules for 404 vs 5xx or unavailable > Yes, max_simple retries should be no more than the total number of parents > -1. > > Let’s say that you have 5 parents and all 5 send back a 404, that’s what > it should be if none of the parents has the object. However, if you set > max_simple_retries greater than the total number of parents, the final > response would be a 502 because all parents were tried and no other parents > are available. So if you have a total of 5 parents, set max_simple_retries > to 4, > Number of parents - 1 > > John > > > On Sep 15, 2022, at 1:23 PM, Nick Dunkin <nick.dun...@vecima.com.INVALID> > wrote: > > > > Hi John, > > > > Thanks for the clarification. > > > > My short term mitigation is going to require me to increase the value of > max_simple_retries. This property is currently fixed in the code to a > maximum values of 5. Are you aware of any reason that I can’t safely > increase that maximum (in the code) to something like 8? My 404 responses > are expected to be very quick, so I’m not too concerned about the > cumulative timing implications that would occur in this rare failover use > case. > > > > Is there anything special about the upper bound value of 5 for this > max_simple_retries property? > > > > Thanks > > > > Nick > > > > From: John Rushford <jjrushf...@gmail.com> > > Date: Thursday, September 15, 2022 at 2:53 PM > > To: dev@trafficserver.apache.org <dev@trafficserver.apache.org> > > Subject: Re: Different parent rules for 404 vs 5xx or unavailable > > Nick, > > > > Currently this is not supported a change would have to be made to > support it. > > > > John Rushford > > jrushf...@apache.org > > > > Sent from my iPhone > > > >> On Sep 15, 2022, at 10:14 AM, Nick Dunkin <nick.dun...@vecima.com.invalid> > wrote: > >> > >> > >> Hi, > >> > >> I have a parent.config rule that uses a primary and secondary set of > parents. > >> > >> Assuming a 404 from a parent in the primary list I would like to > immediately try a parent in the secondary parent list, but for a 5xx, or > connection error, I would like to first exhaust the primary list first, > before then trying the secondary. > >> > >> I would imagine this is a fairly common use case for cluster failover > behavior. i.e. “Content is HTTP 404 form cluster A, so go to cluster B” > >> > >> I am not able to get this use case working with the various options for > secondary_mode in parent.config (ATS ver 9.1.3). > >> > >> Please can anyone provide assistance? Maybe this use case is supported > with strategies.yaml? > >> > >> Thanks > >> > >> Nick > >> > >> Nick Dunkin > >> Director, Software Architecture > >> Manager – Architecture and New Product Introduction > >> o: +1 678.258.4071 > >> e: nick.dun...@vecima.com > >> > >> > >> >
