I tried running `sudo service named-pkcs11 stop` before the yum update, but
FreeIPA still returned NXDOMAIN responses temporarily.
It seems like these responses occur about 10 seconds after the last log
entry in /var/log/ipaupgrade.log ("The ipa-server-upgrade command was
successful"). Based on the IPA "posttrans" script from the RPM, it seems
likely the NXDOMAIN responses are being returned while the `/bin/systemctl
restart ipa.service` command is running, however I cannot reproduce the
NXDOMAIN responses by running `/bin/systemctl restart ipa.service` on its
own. Something in the yum upgrade or ipa-server-upgrade process seems to
trigger this different behaviour.
On Tue, Oct 24, 2017 at 1:45 PM Rob Crittenden <rcrit...@redhat.com> wrote:
> Nicholas Hinds via FreeIPA-users wrote:
> > During an upgrade from 4.5.0-21.el7.centos.1.2
> > to 4.5.0-21.el7.centos.2.2 on a CentOS 7.4 machine, FreeIPA's DNS server
> > briefly returned NXDOMAIN for records which existed in FreeIPA. These
> > invalid responses were returned for a very short amount of time, but
> > caused long-running issues with Java clients which tend to cache DNS
> > responses. Upgraded packages included: 389-ds-base, 389-ds-base-libs,
> > 389-ds-base-snmp, ipa-client, ipa-client-common, ipa-python-compat,
> > ipa-server, ipa-server-common, ipa-server-dns, ipa-server-trust-ad,
> > python2-ipa-server, and a dozen sss-related packages.
> > I reproduced this in a FreeIPA test environment by running `while true;
> > do dig some.dns.entry.managed.by.freeipa @ip.address.of.freeipa | tee -a
> > a-log-file; done` from one server, and running `yum update` on the
> > FreeIPA machine. The invalid NXDOMAIN responses were returned some time
> > after the `yum update` logged 'Cleanup' for the RPMs, and seemed to be
> > during the 'Verifying' phase.
> > These NXDOMAIN responses claimed that an upstream nameserver
> > (a.root-servers.net <http://a.root-servers.net>) was the authority for
> > my zone:
> > a-log-file-; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.37.rc1.el6_7.7 <<>>
> > some.dns.entry.managed.by.freeipa @172.16.0.77 <http://172.16.0.77>
> > a-log-file-;; global options: +cmd
> > a-log-file-;; Got answer:
> > a-log-file:;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 2889
> > a-log-file-;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1,
> > ADDITIONAL: 0
> > a-log-file-
> > a-log-file-;; QUESTION SECTION:
> > a-log-file-;some.dns.entry.managed.by.freeipa. IN A
> > a-log-file-
> > a-log-file-;; AUTHORITY SECTION:
> > a-log-file-.60INSOAa.root-servers.net <http://a.root-servers.net>.
> > nstld.verisign-grs.com <http://nstld.verisign-grs.com>. 2017102400 1800
> > 900 604800 86400
> > a-log-file-
> > a-log-file-;; Query time: 227 msec
> > a-log-file-;; SERVER: 172.16.0.77#53(172.16.0.77)
> > a-log-file-;; WHEN: Tue Oct 24 18:30:28 2017
> > a-log-file-;; MSG SIZE rcvd: 130
> > Usually when querying an invalid DNS entry, the dig output still claims
> > that my FreeIPA server is authoritative for the zone:
> > $ dig doesntexist.zone.managed.by.freeipa @172.16.0.77 <
> > ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.37.rc1.el6_7.7 <<>>
> > doesntexist.zone.managed.by.freeipa @172.16.0.77 <http://172.16.0.77>
> > ;; global options: +cmd
> > ;; Got answer:
> > ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 59953
> > ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
> > ;; QUESTION SECTION:
> > ;doesntexist.zone.managed.by.freeipa. IN A
> > ;; AUTHORITY SECTION:
> > zone.managed.by.freeipa.30 INSOAidm01.freeipa.
> > hostmaster.zone.managed.by.freeipa. 1508869828 30 900 1209600 30
> > ;; Query time: 0 msec
> > ;; SERVER: 172.16.0.77#53(172.16.0.77)
> > ;; WHEN: Tue Oct 24 19:27:12 2017
> > ;; MSG SIZE rcvd: 113
> > Is it possible that during a yum update, the FreeIPA DNS server
> > temporarily forgets what zones it's authoritative for (or forgets all
> > DNS records) and just delegates to the upstream DNS server for half a
> > second or so? Or is something else going on here?
> > I'm open to suggestions.
> The LDAP server is brought down during upgrades which is likely the
> issue. bind can't connect to its backend. Why it returns NXDOMAIN I
> don't know.
> You may be able to manually work around this by manually stopping bind
> before updating IPA, then starting it again afterwards.
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