In the absence of a better mechanism, writing unqualified hostnames to the hosts file may be required
for MagicDNS to work on some Windows environments, such as domain-joined machines. It can also
improve MagicDNS performance on non-domain joined devices when we are not the device's primary
DNS resolver.
At the same time, updating the hosts file can be slow and expensive, especially when it already contains
many entries, as was previously reported in #14327. It may also have negative side effects, such as interfering
with the system's DNS resolution policies.
Additionally, to fix#18712, we had to extend hosts file usage to domain-joined machines when we are not
the primary DNS resolver. For the reasons above, this change may introduce risk.
To allow customers to disable hosts file updates remotely without disabling MagicDNS entirely, whether on
domain-joined machines or not, this PR introduces the `disable-hosts-file-updates` node attribute.
Updates #18712
Updates #14327
Signed-off-by: Nick Khyl <nickk@tailscale.com>
Nick Khyl
9741c1e846