I, too, have observed this, occasionally, under OpenWrt.   If you do figure
this out, or get a solution/explanation off-line, we would really
appreciate an update.

On Wed, Jan 31, 2018 at 1:12 PM, Zi Dvbelju <zidvbe...@gmail.com> wrote:

> *I’m experiencing an issue where all DNS resolutions sent to dnsmasq
> timeout, but only after the dnsmasq service has been successfully running
> for a period of time (anecdotally, after a few weeks of time). After a lot
> of digging, I’ve discovered that dnsmasq’s UDP socket file will eventually
> “disappear”. The issue can be resolved by restarting the dnsmasq service.I
> haven’t been able to reproduce it yet, but it has happened numerous times
> on servers which are running dozens of docker containers. From what I know,
> nothing should be removing this socket file and I can’t find anything
> relevant in the dnsmasq logs. Is anyone aware of any situations that can
> cause socket files to disappear? EnvironmentUbuntu 16.04.3 LTS8 Cores, 16GB
> of RAMDnsmasq 2.75-1ubuntu0.16.04.4BackgroundI’m using dnsmasq to forward
> requests to Consul <https://www.consul.io/docs/guides/forwarding.html>,
> which is used for service discovery. The Consul agent listens on port 8600
> and is configured to bind to all interfaces (the relevant interface here is
>, which docker creates).  Resolv.conf```# Dynamic resolv.conf(5)
> file for glibc resolver(3) generated by resolvconf(8)nameserver
>```Dnsmasq.conf ```server=/consul/
> <>server=/10.in-addr.arpa/
> <>bind-dynamic```Systemd config for
> Docker```ExecStart=/usr/bin/dockerd --bip=
> <> --dns= -H fd://```While investigating the
> servers in the broken state, I observed the following: - nslookup / dig DNS
> resolutions are timing out- Docker logs show containers are also timing out
> on DNS resolutions- Systemd reports that dnsmasq is still running, pid
> still exists - DNS resolutions sent directly to the consul agent
> ( <>) succeed - DNS resolutions sent to
> system[dnsmasq] ( <>) time out- IPV6 UDP
> (::1) resolutions sent to dnsmasq succeeded- Netstat shows that the IPV4
> UDP socket file for dnsmasq is missing- No relevant messages in kernel log
> (specifically, no dnsmasq OOM kill events)- File descriptor usage for the
> entire server was normal- File descriptor usage for the individual dnsmasq
> process was normal- CPU, RAM, and storage all look goodThanks in advance
> for any discussion at all - I've been really struggling with this one for a
> while now.Zach*
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