This has been replaced by `//build:...` for a long time now.
Removal of the old build tag was automated with:
for i in $(git grep -l '^// +build' | grep -v -e '^vendor/'); do if ! grep -q '^// Code generated' "$i"; then sed -i -e '/^\/\/ +build/d' "$i"; fi; done
The semantics (sometimes it returns an error that is really just a
warning) are too confusing, and it turns out that we really only need
it in one place (platformCheckSupported()); after that we've already
figured out what IP families are supported, so we could just use
utiliptables.NewBestEffort() instead, knowing we want exactly what it
returns.
So we can just expand the semantics of the old NewDualStack() inline
in the one place we care, without hiding any of it behind a
too-complicated return value.
Basically all callers want dual-stack-if-possible, so simplify that.
Also, tweak the startup-time checking in kubelet to treat "no iptables
support" as interesting but not an error.
If `iptables --version` failed, utiliptables.New() would log a warning
and assume that the problem was that you had an implausibly ancient
version of iptables installed. Change it to instead assume that the
problem is that you don't have iptables installed at all (and don't
log anything; the caller will discover this later).
It was there so you could mock the results via a FakeExec, but these
days any unit tests outside of pkg/util/iptables that want to mock
iptables results use a FakeIPTables instead of a real
utiliptables.Interface with a FakeExec.
the iptables monitor was using iptables -L to list the chains,
without the -n option, so it was trying to do reverse DNS lookups.
A side effect is that it was holding the lock, so other components
could not use it.
We can use -S instead of -L -n to avoid this, since we only want
to check the chain exists.
iptables has two options to modify the behaviour trying to
acquire the lock.
--wait -w [seconds] maximum wait to acquire xtables lock
before give up
--wait-interval -W [usecs] wait time to try to acquire xtables
lock
interval to wait for xtables lock
default is 1 second
Kubernetes uses -w 5 that means that wait 5 seconds to try to
acquire the lock. If we are not able to acquire it, kube-proxy
fails and retries in 30 seconds, that is an important penalty
on sensitive applications.
We can be a bit more aggresive and try to acquire the lock every
100 msec, that means that we have to fail 50 times to not being
able to succeed.
Kubelet and kube-proxy both had loops to ensure that their iptables
rules didn't get deleted, by repeatedly recreating them. But on
systems with lots of iptables rules (ie, thousands of services), this
can be very slow (and thus might end up holding the iptables lock for
several seconds, blocking other operations, etc).
The specific threat that they need to worry about is
firewall-management commands that flush *all* dynamic iptables rules.
So add a new iptables.Monitor() function that handles this by creating
iptables-flush canaries and only triggering a full rule reload after
noticing that someone has deleted those chains.
The firewalld monitoring code was not well tested (and not easily
testable), would never be triggered on most platforms, and was only
being taken advantage of from one place (kube-proxy), which didn't
need it anyway since it already has its own resync loop.
Since the firewalld monitoring was the only consumer of pkg/util/dbus,
we can also now delete that.
Work around Linux kernel bug that sometimes causes multiple flows to
get mapped to the same IP:PORT and consequently some suffer packet
drops.
Also made the same update in kubelet.
Also added cross-pointers between the two bodies of code, in comments.
Some day we should eliminate the duplicate code. But today is not
that day.
The iptables code was doing version detection on the iptables binary
but feature detection on the iptables-restore binary, to try to
support the version of iptables in RHEL 7, which claims to be 1.4.21
but has certain features from iptables 1.6.
The problem is that this particular set of versions and checks
resulted in the code passing "-w" ("wait forever for the lock") to
iptables, but "-w 5" ("wait at most 5 seconds for the lock") to
iptables-restore. On systems with very very many iptables rules, this
could result in the kubelet periodic resyncs (which use "iptables")
blocking kube-proxy (which uses "iptables-restore") and causing it to
time out.
We already have code to grab the lock file by hand when using a
version of iptables-restore that doesn't support "-w", and it works
fine. So just use that instead, and only pass "-w 5" to
iptables-restore when iptables reports a version that actually
supports it.
- Move from the old github.com/golang/glog to k8s.io/klog
- klog as explicit InitFlags() so we add them as necessary
- we update the other repositories that we vendor that made a similar
change from glog to klog
* github.com/kubernetes/repo-infra
* k8s.io/gengo/
* k8s.io/kube-openapi/
* github.com/google/cadvisor
- Entirely remove all references to glog
- Fix some tests by explicit InitFlags in their init() methods
Change-Id: I92db545ff36fcec83afe98f550c9e630098b3135
