Comment 44 for bug 1674532

We are still encountering intermittent DNS resolution issues, even after an OS reboot. For example:

Net::OpenTimeout: execution expired
                  /usr/lib/ruby/2.3.0/resolv-replace.rb: 25:in `initialize'
                  /usr/lib/ruby/2.3.0/resolv-replace.rb: 25:in `initialize'
                        /usr/lib/ruby/2.3.0/net/smtp.rb: 542:in `open'
                        /usr/lib/ruby/2.3.0/net/smtp.rb: 542:in `tcp_socket'

Environment:

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 14.04.4 LTS
Release: 14.04
Codename: trusty

$ grep '2017-03-2' /var/log/unattended-upgrades/unattended-upgrades.log
2017-03-20 06:42:25,345 INFO Initial blacklisted packages: postgresql redis-server
2017-03-20 06:42:25,346 INFO Starting unattended upgrades script
2017-03-20 06:42:25,347 INFO Allowed origins are: ['o=Ubuntu,a=trusty-security']
2017-03-20 06:42:41,350 INFO No packages found that can be upgraded unattended and no pending auto-removals
2017-03-21 06:35:11,528 INFO Initial blacklisted packages: postgresql redis-server
2017-03-21 06:35:11,531 INFO Starting unattended upgrades script
2017-03-21 06:35:11,531 INFO Allowed origins are: ['o=Ubuntu,a=trusty-security']
2017-03-21 06:35:47,806 INFO Packages that will be upgraded: libc-bin libc-dev-bin libc6 libc6-dev libfreetype6 libgnutls-openssl27 libgnutls26 multiarch-support
2017-03-21 06:35:47,807 INFO Writing dpkg log to '/var/log/unattended-upgrades/unattended-upgrades-dpkg_2017-03-21_06:35:47.807180.log'
2017-03-21 06:35:55,379 INFO All upgrades installed
2017-03-21 06:36:02,861 INFO Packages that are auto removed: ''
2017-03-21 06:36:02,941 INFO Packages auto-removed
2017-03-22 06:31:53,606 INFO Initial blacklisted packages: postgresql redis-server
2017-03-22 06:31:53,607 INFO Starting unattended upgrades script
2017-03-22 06:31:53,607 INFO Allowed origins are: ['o=Ubuntu,a=trusty-security']
2017-03-22 06:32:13,869 INFO Packages that will be upgraded: libc-bin libc-dev-bin libc6 libc6-dev multiarch-support
2017-03-22 06:32:13,870 INFO Writing dpkg log to '/var/log/unattended-upgrades/unattended-upgrades-dpkg_2017-03-22_06:32:13.869840.log'
2017-03-22 06:32:19,722 INFO All upgrades installed
2017-03-22 06:32:25,622 INFO Packages that are auto removed: ''
2017-03-22 06:32:25,668 INFO Packages auto-removed
2017-03-23 06:28:02,799 INFO Initial blacklisted packages: postgresql redis-server
2017-03-23 06:28:02,800 INFO Starting unattended upgrades script
2017-03-23 06:28:02,801 INFO Allowed origins are: ['o=Ubuntu,a=trusty-security']
2017-03-23 06:28:10,368 INFO No packages found that can be upgraded unattended and no pending auto-removals
2017-03-24 06:29:48,590 INFO Initial blacklisted packages: postgresql redis-server
2017-03-24 06:29:48,591 INFO Starting unattended upgrades script
2017-03-24 06:29:48,592 INFO Allowed origins are: ['o=Ubuntu,a=trusty-security']
2017-03-24 06:30:03,308 INFO Packages that will be upgraded: git git-core git-man
2017-03-24 06:30:03,309 INFO Writing dpkg log to '/var/log/unattended-upgrades/unattended-upgrades-dpkg_2017-03-24_06:30:03.308474.log'
2017-03-24 06:30:09,616 INFO All upgrades installed
2017-03-24 06:30:15,645 INFO Packages that are auto removed: ''
2017-03-24 06:30:15,694 INFO Packages auto-removed

$ cat /var/log/unattended-upgrades/unattended-upgrades-dpkg_2017-03-21_06:35:47.807180.log
Preconfiguring packages ...
(Reading database ... 107829 files and directories currently installed.)
Preparing to unpack .../libc6-dev_2.19-0ubuntu6.10_amd64.deb ...
Unpacking libc6-dev:amd64 (2.19-0ubuntu6.10) over (2.19-0ubuntu6.9) ...
Preparing to unpack .../libc-dev-bin_2.19-0ubuntu6.10_amd64.deb ...
Unpacking libc-dev-bin (2.19-0ubuntu6.10) over (2.19-0ubuntu6.9) ...
Preparing to unpack .../libc-bin_2.19-0ubuntu6.10_amd64.deb ...
Unpacking libc-bin (2.19-0ubuntu6.10) over (2.19-0ubuntu6.9) ...
Processing triggers for man-db (2.6.7.1-1ubuntu1) ...
Setting up libc-bin (2.19-0ubuntu6.10) ...
(Reading database ... 107829 files and directories currently installed.)
Preparing to unpack .../libc6_2.19-0ubuntu6.10_amd64.deb ...
Unpacking libc6:amd64 (2.19-0ubuntu6.10) over (2.19-0ubuntu6.9) ...
Setting up libc6:amd64 (2.19-0ubuntu6.10) ...
Processing triggers for libc-bin (2.19-0ubuntu6.10) ...
(Reading database ... 107829 files and directories currently installed.)
Preparing to unpack .../libgnutls-openssl27_2.12.23-12ubuntu2.7_amd64.deb ...
Unpacking libgnutls-openssl27:amd64 (2.12.23-12ubuntu2.7) over (2.12.23-12ubuntu2.6) ...
Preparing to unpack .../libgnutls26_2.12.23-12ubuntu2.7_amd64.deb ...
Unpacking libgnutls26:amd64 (2.12.23-12ubuntu2.7) over (2.12.23-12ubuntu2.6) ...
Preparing to unpack .../libfreetype6_2.5.2-1ubuntu2.6_amd64.deb ...
Unpacking libfreetype6:amd64 (2.5.2-1ubuntu2.6) over (2.5.2-1ubuntu2.5) ...
Preparing to unpack .../multiarch-support_2.19-0ubuntu6.10_amd64.deb ...
Unpacking multiarch-support (2.19-0ubuntu6.10) over (2.19-0ubuntu6.9) ...
Setting up multiarch-support (2.19-0ubuntu6.10) ...
Setting up libc-dev-bin (2.19-0ubuntu6.10) ...
Setting up libc6-dev:amd64 (2.19-0ubuntu6.10) ...
Setting up libgnutls26:amd64 (2.12.23-12ubuntu2.7) ...
Setting up libgnutls-openssl27:amd64 (2.12.23-12ubuntu2.7) ...
Setting up libfreetype6:amd64 (2.5.2-1ubuntu2.6) ...
Processing triggers for libc-bin (2.19-0ubuntu6.10) ...

$ cat /var/log/unattended-upgrades/unattended-upgrades-dpkg_2017-03-22_06:32:13.869840.log
Preconfiguring packages ...
(Reading database ... 107829 files and directories currently installed.)
Preparing to unpack .../libc6-dev_2.19-0ubuntu6.11_amd64.deb ...
Unpacking libc6-dev:amd64 (2.19-0ubuntu6.11) over (2.19-0ubuntu6.10) ...
Preparing to unpack .../libc-dev-bin_2.19-0ubuntu6.11_amd64.deb ...
Unpacking libc-dev-bin (2.19-0ubuntu6.11) over (2.19-0ubuntu6.10) ...
Preparing to unpack .../libc-bin_2.19-0ubuntu6.11_amd64.deb ...
Unpacking libc-bin (2.19-0ubuntu6.11) over (2.19-0ubuntu6.10) ...
Processing triggers for man-db (2.6.7.1-1ubuntu1) ...
Setting up libc-bin (2.19-0ubuntu6.11) ...
(Reading database ... 107829 files and directories currently installed.)
Preparing to unpack .../libc6_2.19-0ubuntu6.11_amd64.deb ...
Unpacking libc6:amd64 (2.19-0ubuntu6.11) over (2.19-0ubuntu6.10) ...
Setting up libc6:amd64 (2.19-0ubuntu6.11) ...
Processing triggers for libc-bin (2.19-0ubuntu6.11) ...
(Reading database ... 107829 files and directories currently installed.)
Preparing to unpack .../multiarch-support_2.19-0ubuntu6.11_amd64.deb ...
Unpacking multiarch-support (2.19-0ubuntu6.11) over (2.19-0ubuntu6.10) ...
Setting up multiarch-support (2.19-0ubuntu6.11) ...
Setting up libc-dev-bin (2.19-0ubuntu6.11) ...
Setting up libc6-dev:amd64 (2.19-0ubuntu6.11) ...

$ apt-cache show libc6 | grep Version
Version: 2.19-0ubuntu6.11
Version: 2.19-0ubuntu6