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.
This should fix a bug that could break masters when the EndpointSlice
feature gate was enabled. This was all tied to how the apiserver creates
and manages it's own services and endpoints (or in this case endpoint
slices). Consumers of endpoint slices also need to know about the
corresponding service. Previously we were trying to set an owner
reference here for this purpose, but that came with potential downsides
and increased complexity. This commit changes behavior of the apiserver
endpointslice integration to set the service name label instead of owner
references, and simplifies consumer logic to reference that (both are
set by the EndpointSlice controller).
Additionally, this should fix a bug with the EndpointSlice GenerateName
value that had previously been set with a "." as a suffix.
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.
As mentioned in issue #80061, in iptables lock contention case,
we can see increasing rate of iptables restore failures because it
need to grab iptables file lock.
The failure metric can provide administrators more insight
Metrics will be collected in kube-proxy iptables and ipvs modes
Signed-off-by: Hui Luo <luoh@vmware.com>
Kube-proxy's iptables mode used to care whether utiliptables's
EnsureRule was able to use "iptables -C" or if it had to implement it
hackily using "iptables-save". But that became irrelevant when
kube-proxy was reimplemented using "iptables-restore", and no one ever
noticed. So remove that check.
Currently the BaseServiceInfo struct implements the ServicePort interface, but
only uses that interface sometimes. All the elements of BaseServiceInfo are exported
and sometimes the interface is used to access them and othertimes not
I extended the ServicePort interface so that all relevent values can be accessed through
it and unexported all the elements of BaseServiceInfo
This adds some useful metrics around pending changes and last successful
sync time.
The goal is for administrators to be able to alert on proxies that, for
whatever reason, are quite stale.
Signed-off-by: Casey Callendrello <cdc@redhat.com>
As part of the endpoint creation process when going from 0 -> 1 conntrack entries
are cleared. This is to prevent an existing conntrack entry from preventing traffic
to the service. Currently the system ignores the existance of the services external IP
addresses, which exposes that errant behavior
This adds the externalIP addresses of udp services to the list of conntrack entries that
get cleared. Allowing traffic to flow
Signed-off-by: Jacob Tanenbaum <jtanenba@redhat.com>
We REJECT every other case. Close this FIXME.
To get this to work in all cases, we have to process service in
filter.INPUT, since LB IPS might be manged as local addresses.
