on startup gateway & dns- options in /etc/network/interfaces are not always set

Comment lines from the "base" file are always omitted from resolv.conf. Try adding a line "search bogus.com“ and see if "bogus.com" shows up on the "search" line in resolv.conf.

thank you. that of course worked (apologies for not fully understanding the parsing of the base file). interestingly enough, with that search addition in the base file, now the settings from /etc/network/interfaces are now showing up in resolv.conf (bogus.com is appended to the other dns-search settings) .... and on 3 successive startups.

Obviously the presence of material in the "base" file should have no effect on the processing of material from /etc/network/interfaces. Are you still sure that material from /e/n/i is sometimes incorrectly omitted from the /etc/resolv.conf file?

well i've now been able to restart 3 of the 4 systems about 5-10x each through the day. all have had their gateway and dns- settings from /e/n/i reliably set. that is, until now. i've got one system that did not get gateway or dns- settings.

is there a way to check for a failure status code tied to ifup or resolvconf runs during startup?

$ cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet static
  address x.y.105.96
  netmask 255.255.252.0
# network x.y.104.0
  broadcast x.y.107.255
  gateway x.y.107.250
# dns-* options are implemented by the resolvconf package, if installed
  dns-nameserver x.y.105.44
  dns-nameserver x.y.147.98
  dns-search r.mydomain s.mydomain t.mydomain

$ cat /etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN

note: i have since removed the comments from base & tail.

note see package ifupdown bug #1573272. it would seem related but note that dns- settings are also problematic.

Are there cases where the interface is configured properly but resolv.conf is not updated to include material from the dns-* lines?

yes i think all of them. the interface appears to always be configured correctly. however, sometimes the default gateway is not set, other times the dns- settings are not set, and still other times neither are set.

bump! definitely a repeatable issue albeit sporadically. lost another system on reboot - no default gateway installed although it's set in /e/n/i. have to manually add route via rc.local and symlink /etc/resolv.conf.d/resolv.conf original to tail as workarounds.

> well i've now been able to restart 3 of the 4 systems about 5-10x each through the day. all have
> had their gateway and dns- settings from /e/n/i reliably set. that is, until now. i've got one
> system that did not get gateway or dns- settings.

The gateway is set directly from ifup (by calling 'ip route add default via ...'). But the resolv.conf entries are set by the /etc/network/if-up.d/000resolvconf script, which is only run if all other interface configuration succeeded, so if you're missing the dns that could just mean some other part of the interface setup failed (e.g. setting the gateway).

> is there a way to check for a failure status code tied to ifup or resolvconf runs during startup?

are you using upstart or systemd? For upstart look in the /var/log/upstart/network* log files, for systemd look in /var/log/syslog.

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