dovecot - Jan 2020 - Upgrade 2.2.27 to 2.3.9.2: master(imap): net_connect_unix(imap) failed: Resource temporarily unavailable

On 08/01/2020 10:49, Eirik Rye wrote:
> [...]
In any case, the biggest issue is the one described in the original 
message in this thread, where logins are periodically failing for many 
for users:

2020-01-08T10:54:57.436400+01:00 imap dovecot: imap-login: Error: 
master(imap): net_connect_unix(imap) failed: Resource temporarily 
unavailable - http://wiki2.dovecot.org/SocketUnavailable
2020-01-08T10:54:57.437550+01:00 imap dovecot: imap-login: Internal 
login failure

At the same time:

~# ps aux | grep "dovecot/imap$" | wc -l
6637
~# doveadm process status | grep "^imap " | wc -l
6660
~# cat /proc/`pidof dovecot`/limits | grep "open files"
Max open files            32768                32768                files
~# doveconf -n
[...]
service imap-login {
   client_limit = 2500
   inet_listener imap {
     port = 143
   }
   inet_listener imaps {
     port = 993
     ssl = yes
   }
   process_limit = 16
   process_min_avail = 16
   service_count = 0
   vsz_limit = 512 M
}
service imap {
   client_limit = 1
   process_limit = 20000
}

-- 
Eirik

Can you enable 'verbose_proctitle=yes' and maybe compare with ss -tp
output?

Aki
> On 08/01/2020 11:58 Eirik Rye <rye at domeneshop.no> wrote:
> 
>  
> On 08/01/2020 10:49, Eirik Rye wrote:
> > [...]
> 
> In any case, the biggest issue is the one described in the original 
> message in this thread, where logins are periodically failing for many 
> for users:
> 
> 2020-01-08T10:54:57.436400+01:00 imap dovecot: imap-login: Error: 
> master(imap): net_connect_unix(imap) failed: Resource temporarily 
> unavailable - http://wiki2.dovecot.org/SocketUnavailable
> 2020-01-08T10:54:57.437550+01:00 imap dovecot: imap-login: Internal 
> login failure
> 
> At the same time:
> 
> ~# ps aux | grep "dovecot/imap$" | wc -l
> 6637
> ~# doveadm process status | grep "^imap " | wc -l
> 6660
> ~# cat /proc/`pidof dovecot`/limits | grep "open files"
> Max open files            32768                32768                files
> ~# doveconf -n
> [...]
> service imap-login {
>    client_limit = 2500
>    inet_listener imap {
>      port = 143
>    }
>    inet_listener imaps {
>      port = 993
>      ssl = yes
>    }
>    process_limit = 16
>    process_min_avail = 16
>    service_count = 0
>    vsz_limit = 512 M
> }
> service imap {
>    client_limit = 1
>    process_limit = 20000
> }
> 
> -- 
> Eirik

On 08/01/2020 11:09, Aki Tuomi wrote:
> Can you enable 'verbose_proctitle=yes' and maybe compare with ss
-tp output?
Thanks for the response!

What exactly did you want to compare? `ss -tp` does not appear to show 
cmdline/process title. I enabled it for one server, but will have to 
wait for users to reconnect and for the issue to reappear there.

In the meantime, on another server experiencing the same issue at this 
moment (same configuration), but no proctitles:

root at imap03:~# doveadm process status | grep "^imap " | wc -l
7564
root at imap03:~# ps aux | grep "dovecot/imap$" | wc -l
7570
root at imap03:~# ss -tp | grep '"imap-login"' | wc -l
8009
root at imap03:~# ss -tp | grep '"imap"' | wc -l
536
root at imap03:~# ss -nt "( sport = :143 or sport = :993 )" | wc -l
8739
root at imap03:~# doveadm who -1 | wc -l
7581

The `ss -tp` output appears normal (e.g. 8009+536 ~= 8739).

-- 
Eirik