Differentiate headless services from ClusterIP being none, in
preparation for handling the service.kubernetes.io/headless label. One
might thing that handling these is similar, which it sort of is and sort
of isn't. ClusterIP is an immutable field, whereas labels are mutable.
This changes our handling of ClusterIP none-ness from the presence of
the headless label.
When we consider what to do with ClusterIP being none, that is
fundamentally different, because once it is None, the k8s API guarantees
that the service won't ever change.
Whereas the label can be added and removed.
This is a feature that has been requested a few times over the years and
would bring us closer to feature parity with other k8s network
implementations for service proxy.
In some cases it is possible for Endpoint.Conditions.Ready to be nil
during the early stages of initialization. When this happens it causes
kube-router to segfault. This fix tests for nil before testing for
Ready.
It used to be that the kubelet handled setting hairpin mode for us:
https://github.com/kubernetes/kubernetes/pull/13628
Then this functionality moved to the dockershim:
https://github.com/kubernetes/kubernetes/pull/62212
Then the functionality was removed entirely:
https://github.com/kubernetes/kubernetes/commit/83265c9171f
Unfortunately, it was lost that we ever depended on this in order for
our hairpin implementation to work, if we ever knew it at all.
Additionally, I suspect that containerd and cri-o implementations never
worked correctly with hairpinning.
Without this, the NAT rules that we implement for hairpinning don't work
correctly. Because hairpin_mode isn't implemented on the virtual
interface of the container on the host, the packet bubbles up to the
kube-bridge. At some point in the traffic flow, the route back to the
pod gets resolved to the mac address inside the container, at that
point, the packet's source mac and destination mac don't match the
kube-bridge interface and the packet is black-holed.
This can also be fixed by putting the kube-bridge interface into
promiscuous mode so that it accepts all mac addresses, but I think that
going back to the original functionality of enabling hairpin_mode on the
veth interface of the container is likely the lesser of two evils here
as putting the kube-bridge interface into promiscuous mode will likely
have unintentional consequences.
Before this, we had 2 different ways to interact with ipsets, through
the handler interface which had the best handling for IPv6 because NPC
heavily utilizes it, and through the ipset struct which mostly repeated
the handler logic, but didn't handle some key things.
NPC utilized the handler functions and NSC / NRC mostly utilized the old
ipset struct functions. This caused a lot of duplication between the two
groups of functions and also caused issues with proper IPv6 handling.
This commit consolidates the two sets of usage into just the handler
interface. This greatly simplifies how the controllers interact with
ipsets and it also reduces the logic complexity on the ipset side.
This also fixes up some inconsistency with how we handled IPv6 ipset
names. ipset likes them to be prefixed with inet6:, but we weren't
always doing this in a way that made sense and was consistent across all
functions in the ipset struct.
With the advent of IPv6 integrated into the NSC we no longer get all IPs
from endpoints, but rather just the primary IP of the pod (which is
often, but not always the IPv4 address).
In order to get all possible endpoint addresses for a given service we
need to switch to using EndpointSlice which also nicely groups addresses
into IPv4 and IPv6 by AddressType and also gives us more information
about the endpoint status by giving us attributes for serving and
terminating, instead of just ready or not ready.
This does mean that users will need to add another permission to their
RBAC in order for kube-router to access these objects.
There is absolutely no reason that we should ever assume netmasks, and
even if we did, we shouldn't modify them as a side-effect of a
completely different operation. No idea was this was ever coded this
way. Netmask is now set upstream to the appropriate mask for the IP
family.
During our initial run, fail fatally when we encounter problems rather
than just continuing on and causing subsequent problems and potentially
burying the real error.
This change allows to define two cluster CIDRs for compatibility with
Kubernetes dual-stack, with an assumption that two CIDRs are usually
IPv4 and IPv6.
Signed-off-by: Michal Rostecki <vadorovsky@gmail.com>
Previously, we would iterate over rulesFromNode, but then check it
against the entirety of the rulesNeeded hash. This resulted in the loop
breaking as soon as it found any matching rule from the host rather than
it breaking if it matched the rule that we were currently processing.
When we receive service or endpoint updates from Kubernetes we process a
type of partial sync because the service and endpoints have already been
updated by the handler. However, previously, this partial update did not
include updating the hairpinning rules for services.
This would cause hairpinning changes to be delayed until the next full
sync or until kube-router restart. This changes adds hairpinning into
the partial service sync flow.
* fact(NSC): consolidate constants to top
* fix(NSC): increase IPVS add service logging
* fix(NSC): improve logging for FWMark IPVS entries
* fix(NSC): add missing parameter to logging
* feat(NSC): generate unique FW marks
Because we trim the 32-bit FNV-1a hash to 16 bits there is the potential
for FW marks to collide with each other even for unique inputs of IP,
protocol, and port. This reduces that chance up to the 16-bit max by
keeping track of which FW marks we've already allocated and what IP,
protocol, port combo they've been allocated for.
Fixes#1045
* fact(NSC): move utility funcs to utils
* fix(NSC): reduce IPVS service shell outs
This also aligns it more with the almost identical function used for
non-FWmarked services ipvsAddService() which is also called from
setupExternalIPServices and passes in this same list of ipvsServices.
* fix(NSC): fix & consolidate DSR cleanup code
A lot of this is refactor work, but its important to know why the DSR
mangle tables were not being cleaned up in the first place. When we
transitioned to iptables-save to look over the mangle rules, we didn't
realize that iptables-save changes the format of the marks from integer
values (which is what the CLI works with) to hexadecimal.
This made it so that we were never actually matching on a mangle rule,
which left them all behind. When these mangle rules were left, it meant
that IPs that used to be part of a DSR service were essentially
black-holed on the system and were no longer route-able.
Fixes#1167
* doc(dsr): expand DSR documentation
fixes#1055
* ensure active service map is updated for non DSR services
Co-authored-by: Murali Reddy <muralimmreddy@gmail.com>
I found that without taking a brief pause between iptables cleanup and
ipset deletion, sometimes the system still thought that there were
iptables references to the ipsets and would error instead of cleaning
the ipsets.
* remove IPVS metrics
Remove metrics for IPVS services when the IPVS service is deleted so
that the number of metrics does not grow without bound.
Fixes#734
* delete metricsMap key when IPVS service is removed
Delete the key in NetworkServicesController.metricsMap when the
respective IPVS configuration is removed.
Remove a period from a comment to conform to kube-router norms
* cleanup stale metrics in a distinct method
* remove unnecessary error return value on cleanupStaleMetrics
