Alexey Serbin has posted comments on this change. ( http://gerrit.cloudera.org:8080/23213 )
Change subject: [net] use AF_INET hint for GetFQDN() ...................................................................... Patch Set 3: > > > Why did we not hit this issue before? Is it because we always > > > tested on nodes with IPv6 disabled or something? > > > > We have always been hitting this issue, even before. At least I > > have always had it on my laptop with Clodera's VPN enabled. I've > > just found it intolerable this time since it was slowing my > > development cycle :) > > > > > So is my understanding correct - without the fix we end up > > hitting > > > both IPv6 and IPv4 resolvers at some point and the faulty IPv6 > > > resolver is causing the slowness? By explicitly declaring > > AF_INET, > > > we are not hitting that issues. > > > > I didn't spend my time on doing the precise RCA, but I found that > > limiting the DNS query just for IPv4 addresses solves the issue. > > If not adding the AF_INET family hint, adding extra records for > > IPv6 addresses into the /etc/hosts would help in my particular > case > > as well. Having this address family hint is a good option > because: > > (1) it allows for not hitting the issue with mis-configured IPv6 > > resolver without extra changes in /etc/hosts (2) it unifies the > way > > how IP addresses are resolved now in util/net (we limit > everything > > to IPv4 since we don't support IPv6 yet). > > I didn't notice this during IPv6 testing (even with VPN enabled). > Maybe my laptop's name service switch order/local config allows > resolution to happen faster. > > Maybe it is ok for now to look for IPv4 addresses only. > With IPv6 changes, we would need to change it back or maybe set the > hint to AF_UNSPEC (which is same as having nothing set). > Also, the signature of GetFQDN will probably change in order to > ensure > both IPv4 and IPv6 address info. Caller will need to decide which > one > to use. Currently, we are randomly returning first entry which is > not > guaranteed to be IPv4 or IPv6 when hint is unspecified. I agree: we need to be more consistent with IPv4/IPv6 preference, especially when IPv6 support is explicitly enabled. As for particular manifestation of the issue, the problem was visible when calling GetFQDN() for the local name of the machine that was originally assigned by local network's DHCP server, and then VPN of other outside network was enabled. -- To view, visit http://gerrit.cloudera.org:8080/23213 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: kudu Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: Ibca0a3c1f7ad03a6f847057c38c00b42275dec8b Gerrit-Change-Number: 23213 Gerrit-PatchSet: 3 Gerrit-Owner: Alexey Serbin <[email protected]> Gerrit-Reviewer: Abhishek Chennaka <[email protected]> Gerrit-Reviewer: Alexey Serbin <[email protected]> Gerrit-Reviewer: Ashwani Raina <[email protected]> Gerrit-Reviewer: Gabriella Lotz <[email protected]> Gerrit-Reviewer: Kudu Jenkins (120) Gerrit-Comment-Date: Fri, 25 Jul 2025 18:01:13 +0000 Gerrit-HasComments: No
