DNS lookups will switch to TCP if the response is larger than can fit in a single packet. But that should happen immediately.
On Thu, Aug 25, 2022 at 5:56 AM terrible person <[email protected]> wrote: > Hi. I'm currently debugging DNS Lookup warnings (more that 3 sec) and need > to figure out whether our network/our DNS/or exporter is misbehaving. > So I'm checking ssh endpoints with tcp module: > > [image: 2022-08-25_13-22-13.png] > > but experience 3+ seconds delay on resolving ssh hostnames, which triggers > alerts DNSLookupDuration3s. > > [image: 2022-08-25_13-26-19.png] > problem looks something like this on different hosts - 3.0s+ seconds of > timeout, which looks very much like a generic tcp timeout. > > I checked on DNS server and yes, after UDP queries there is a TCP DNS > query for A record. I don't see any UDP checksum corruption or delays for > such failover. Is this intended? Can someone help me out on this. > > -- > You received this message because you are subscribed to the Google Groups > "Prometheus Users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/prometheus-users/16d8f137-a7e3-4361-a624-6719d71b1d29n%40googlegroups.com > <https://groups.google.com/d/msgid/prometheus-users/16d8f137-a7e3-4361-a624-6719d71b1d29n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "Prometheus Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/prometheus-users/CABbyFmpW1EJLi3OUhu8MC9ZNk8aGgpHN3Gg15_zRcbfx4FE4Jg%40mail.gmail.com.
