I'll take a look, but the DNS failover is about nameserver failover, not upstream failover.
1) Yes, should be able to set this via the server retry settings. See here - https://docs.trafficserver.apache.org/en/7.1.x/admin-guide/files/records.config.en.html#proxy-config-http-connect-attempts-max-retries - "proxy.config.http.connect_attempts_rr_retries" may be of interest as well. 3) Yes, that should be the default behavior. See here - https://docs.trafficserver.apache.org/en/7.1.x/admin-guide/files/records.config.en.html#proxy-config-http-server-session-sharing-match On Thu, May 31, 2018 at 6:29 PM, salil GK <gksa...@gmail.com> wrote: > Can I get some ad hoc document for the dns failover. This is pretty > much urgent for me for my solution. > > Thanks and regards > ~S > > On 30 May 2018 at 04:45, salil GK <gksa...@gmail.com> wrote: > > Thanks Susan for the reply. > > > > Can I get some help on dns failover settings. > > Basically if dns server return multiple A records, how can I setup ATS > > to select alternative IP address in case first IP address is not > > accessible. > > > > Thanks > > ~S > > > > On 29 May 2018 at 20:19, Susan Hinrichs <shinr...@oath.com.invalid> > wrote: > >> We need to file an issue on getting these documented. Judging from "git > >> blame" . the failover settings have been around for quite a while. I > >> cannot help you much with the failover settings, since I haven't worked > in > >> that area. > >> > >> I can help you on some of the other settings since Fei and I have been > >> digging through here recently. > >> > >> proxy.config.dns.max_dns_in_flight Controls how many DNS requests are > >> allowed to be outstanding. If this limit is reached, further requests > will > >> be delayed until some responses arrive. I think this is a per thread > limit. > >> > >> proxy.config.dns.lookup_timeout The timeout in seconds on a DNS > request. > >> > >> proxy.config.dns.retries Number of times ATS will retry a DNS request. > >> > >> proxy.config.dns.local_ipv4 > >> proxy.config.dns.local_ipv6 Specify the source address ATS uses to make > DNS > >> requests. NULL will pull the IP address from the interface > >> > >> > >> > >> > >> > >> > >> On Mon, May 28, 2018 at 7:34 PM, gksa...@gmail.com <gksa...@gmail.com> > >> wrote: > >> > >>> > >>> > >>> On 2018/05/25 16:27:08, salil GK <gksa...@gmail.com> wrote: > >>> > Hello > >>> > > >>> > I have a ATS ( 6.2.2 ) deployed in my server for Forward proxy. > My > >>> > deployment is as follows > >>> > > >>> > > >>> > client -> ATS-1 -> ATS-2 -> "Origin server” > >>> > > >>> > Here between ATS-1 and ATS-2 I have created ssh tunnels and > >>> > traffic will be passed through that tunnel, using parent.config. > >>> > > >>> > ATS-1 is opening a MTLS socket to client and "Origin server" is > https > >>> > > >>> > I have some questions regarding the capability of ATS. > >>> > > >>> > 1. From ATS-2 there will be a dns A query and get the address > resolved > >>> > before connecting to "Origin Server” > >>> > If dns server return 2 or three addresses, is there any > way > >>> > ATS use the alternative address ( second or third ) in case it fails > >>> > to reach first address ? How dns resolution works in ATS, is the dns > >>> > functionality embedded in dns or it allow the system to resolve the > >>> > address ? > >>> > > >>> > 2. I have a cluster of ATS-2 ( two ATS-2 machines.) in my > >>> > parent.config I have specified these two ATS-2 machines and > >>> > round_robin parameters is set to true. From document, I guess the > >>> > round_robin will happen if request come from different IP addresses ( > >>> > ? ). All requests come from same IP address will take same parent > >>> > machine only. Is there any way I can have round robin in place even > >>> > for requests come from same IP address ? > >>> > > >>> > 3. Is there any chance that http connection to origin server from > >>> > ATS-2 can be made persistent. > >>> > > >>> > 4. Since this is multi hop deployment I need to handle error > >>> > condition in ATS-1 and ATS-2 gracefully. So based on the HTTP > response > >>> > code, I would like to put some logic for handling this. For example, > >>> > if an error is returned from the origin server, or if there is any > >>> > network issue between ATS-2 and origin server, I need to handle it in > >>> > ATS-1 ( logging or try another ATS-2 etc ). How do I achieve this ? > >>> > > >>> > > >>> > Any help on this would be of great help for me. > >>> > > >>> > Thanks > >>> > ~S > >>> > > >>> > >>> While searching in the web, I have seen some configuration variables > >>> related to dns > >>> > >>> proxy.config.dns.failover_number INT 5 > >>> proxy.config.dns.failover_period INT 60 > >>> proxy.config.dns.local_ipv4 STRING NULL > >>> proxy.config.dns.local_ipv6 STRING NULL > >>> proxy.config.dns.lookup_timeout INT 20 > >>> proxy.config.dns.max_dns_in_flight INT 2048 > >>> proxy.config.dns.retries INT 5 > >>> > >>> Where do I get the document related to these parameters ? > >>> > >>> This is a bit urgent issue for me to resolve this issue. It would be > of > >>> great help if I get some directions on this. > >>> > >>> Thanks in advance > >>> ~S > >>> >
