Ubuntu 18.04: systemd-resolved -- crashing or failing to start properly...

[Robert Heller]

At Sat, 1 Jun 2019 12:31:11 +0200 "Ubuntu user technical support,  not for general discussions" <ubuntu-users at lists.ubuntu.com> wrote:

> 
> On Sat, Jun 1, 2019 at 2:29 AM Robert Heller <heller at deepsoft.com> wrote:
> >
> > I have an *intermittent* problem with systemd-resolved. It is
> > either crashing or fails to start properly. The sympton is that
> > when I go to do an update (eg apt-get update), I get name resolver
> > errors to the *local* (LAN only) mirror host. Doing a "systemctl
> > restart systemd-resolved" cures the problem. I am not sure exactly
> > what is going on, but it appears that for some reason
> > systemd-resolved is not seeing (or using) the *local* LAN DNS
> > server (bind9 running on a CentOS 6 server). For *all* of the
> > Ubuntu 18.04 machines, *I* would *rather* not have systemd-resolved
> > running at all and just have /etc/resolve.conf reference the CentOS
> > 6 server and bind9 running there. (I have configured things on the
> > DRBL server to do just that.) It is already a cacheing DNS server
> > for the whole LAN and provides local DNS for the LAN, including
> > intranet services (NFS server, LDAP server, LAN-only web services,
> > etc.). The problem is an issue on the laptops and one workstation,
> > and only really affects LAN-only web services (which includes the
> > local repo mirror) -- the NFS mounts and LDAP configuration use the
> > hard IP address of the server(s) in question.
> 
> [ It's "/etc/resolv.conf" not "/etc/resolve.conf" but I assume that
> this is an email typo not an on-filesystem one ]

Yes...

> 
> Are you feeding "systemd-resolved" the LAN DNS server? What's the
> output of "resolvectl"?
> 

systemd-resolved should be get parameters via DHCP from the DHCP server:

(From the dhcpd.conf file on the CentOS 6 machine:

  option domain-name "wendellfreelibrary.org";
  option domain-name-servers 192.168.1.251, 8.8.8.8, 8.8.4.4;
  option broadcast-address 192.168.1.255;
  option routers 192.168.1.251;
        
)

There is no resolvectl program.  It does not appear to be installed on my 
Ubuntu 18.05 system.


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