5e93ebec1e
Addresses #5811 This cleans up an error in the logic which removes localhost resolvers from the host resolv.conf at container creation start time. Specifically when the determination is made if any nameservers are left after removing localhost resolvers, it was using a string match on the word "nameserver", which could have been anywhere (including commented out) leading to incorrect situations where no nameservers were left but the default ones were not added. This also adds some complexity to the regular expressions for finding nameservers in general, as well as matching on localhost resolvers due to the recent addition of IPv6 support. Because of IPv6 support now available in the Docker daemon, the resolvconf code is now aware of IPv6 enable/disable state and uses that for both filter/cleaning of nameservers as well as adding default Google DNS (IPv4 only vs. IPv4 and IPv6 if IPv6 enabled). For all these changes, tests have been added/strengthened to test these additional capabilities. Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com> (github: estesp) Upstream-commit: 93d51e5e971e001d80e9ffa863439f2d72215b5a Component: engine