A service with a NodePort set will listen on that port, on every node.
This is both handy for some load balancers (AWS ELB) and for people
that want to expose a service without using a load balancer.
After this DNS is resolvable from the host, if the DNS server is targetted
explicitly. This does NOT add the cluster DNS to the host's resolv.conf. That
is a larger problem, with distro-specific tie-ins and circular deps.
The iptables args list needs to include all fields as they are eventually spit
out by iptables-save. This is because some systems do not support the
'iptables -C' arg, and so fall back on parsing iptables-save output. If this
does not match, it will not pass the check. For example: adding the /32 on
the destination IP arg is not strictly required, but causes this list to not
match the final iptables-save output. This is fragile and I hope one day we
can stop supporting such old iptables versions.
This makes iptables an injectable dependency. The test for this started off
simple, but got a bit out of hand. It's starting to become a mocking
framework.
BenTheElder