CentOS - Jul 2017 - System Start-Up Issue Progress

Once again, my thanks to all that responded to my posting about our
virtual machine CentOS 6 system start-up issue.? Addressing sendmail
was the key to the start-up issue.

While operating at Run Level 1, chkconfig sendmail off was commanded
followed by the reboot command.? This brought up the system with the
complete and operational GUI interface.

The maillog had several entries from the past few days.? Possibly the
most telling of these messages are included below:

computer sendmail[nnnn]: unable to qualify my own domain name (computer)

computer sendmail[mmmm]: My unqualified host name (computer) unknown;
sleeping for retry

During the days that we were attempting to troubleshoot the problem,
the boot-up process was left on one occasion for about one hour. It
appears that the sleeping for retry may have been inspired by that
famous gentleman R.V. Winkle.

Since we do not need sendmail on this system, we will just leave it
turned off along with IPMI features.

It remains a mystery what could have happened during a standard yum
update of the system to cause this domain and/or host related sendmail
issue. 

    On Tuesday, July 4, 2017 7:14 AM, Jonathan Billings <billings at
negate.org> wrote:
 

 On Jul 4, 2017, at 8:01 AM, Chris Olson <chris_e_olson at yahoo.com>
wrote:
> Starting ipmidetectd: ipmidetectd: No nodes configured? [FAILED]
> Starting sendmail:

Any chance that this system doesn?t have valid DNS lookups?

What I see above is that ipmidetetd failed (which doesn?t block) and then it is
stuck starting sendmail.? If memory serves me (I haven?t used sendmail in years)
sendmail gets stuck waiting for a response from DNS servers when it?s performing
part of its startup.

--
Jonathan Billings <billings at negate.org>


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On 07/04/2017 09:21 AM, Chris Olson wrote:
> It remains a mystery what could have happened during a standard yum
> update of the system to cause this domain and/or host related sendmail
> issue.

Run "hostname".  Has the hostname changed?  Run "ls -l /etc/hosts
/etc/resolv.conf".  Have those files changed recently?

It's possible that this system was working in the past because its 
hostname was set up in DNS, and was removed.  In that case, the problem 
wasn't related to "yum."   sendmail would (IIRC) continue working
after
the system's hostname was removed from DNS, until the next time the 
system rebooted.

Am 04.07.2017 um 19:13 schrieb Gordon Messmer:
> On 07/04/2017 09:21 AM, Chris Olson wrote:
>> It remains a mystery what could have happened during a standard yum
>> update of the system to cause this domain and/or host related sendmail
>> issue.
> 
> 
> Run "hostname".  Has the hostname changed?  Run "ls -l
/etc/hosts
> /etc/resolv.conf".  Have those files changed recently?
> 
> It's possible that this system was working in the past because its 
> hostname was set up in DNS, and was removed.  In that case, the problem 
> wasn't related to "yum."   sendmail would (IIRC) continue
working after
> the system's hostname was removed from DNS, until the next time the 
> system rebooted.
Sendmail demands a hostname with at least a single dot in it.
"computer"
is in no way a valid FQDN. "computer.localdomain" would be fine and if
it has an entry in /etc/hosts.

Alexander