The nat KUBE-SERVICES chain is called from OUTPUT and PREROUTING stages. In
clusters with large number of services, the nat-KUBE-SERVICES chain is the largest
chain with for eg: 33k rules. This patch aims to move the KubeMarkMasq rules from
the kubeServicesChain into the respective KUBE-SVC-* chains. This way during each
packet-rule matching we won't have to traverse the MASQ rules of all services which
get accumulated in the KUBE-SERVICES and/or KUBE-NODEPORTS chains. Since the
jump to KUBE-MARK-MASQ ultimately sets the 0x400 mark for nodeIP SNAT, it should not
matter whether the jump is made from KUBE-SERVICES or KUBE-SVC-* chains.
Specifically we change:
1) For ClusterIP svc, we move the KUBE-MARK-MASQ jump rule from KUBE-SERVICES
chain into KUBE-SVC-* chain.
2) For ExternalIP svc, we move the KUBE-MARK-MASQ jump rule in the case of
non-ServiceExternalTrafficPolicyTypeLocal from KUBE-SERVICES
chain into KUBE-SVC-* chain.
3) For NodePorts svc, we move the KUBE-MARK-MASQ jump rule in case of
non-ServiceExternalTrafficPolicyTypeLocal from KUBE-NODEPORTS chain to
KUBE-SVC-* chain.
4) For load-balancer svc, we don't change anything since it is already svc specific
due to creation of KUBE-FW-* chains per svc.
This would cut the rules per svc in KUBE-SERVICES and KUBE-NODEPORTS in half.
kube-proxy expose the metric network_programming_duration_seconds,
that is defined as the time it takes to program the network since
a a service or pod has changed. It uses an annotation on the endpoints
/endpointslices to calculate when the endpoint was created, however,
on restarts, kube-proxy process all the endpoints again, no matter
when those were generated, polluting the metrics.
To be safe, kube-proxy will estimate the latency only for those
endpoints that were generated after it started.
1. Do not describe port type in message because lp.String() already has the
information.
2. Remove duplicate error detail from event log.
Previous log is like this.
47s Warning listen tcp4 :30764: socket: too many open files node/127.0.0.1 can't open port "nodePort for default/temp-svc:834" (:30764/tcp4), skipping it: listen tcp4 :30764: socket: too many open files
[issue]
When creating a NodePort service with the kubectl create command, the NodePort
assignment may fail.
Failure to assign a NodePort can be simulated with the following malicious
command[1].
$ kubectl create service nodeport temp-svc --tcp=`python3 <<EOF
print("1", end="")
for i in range(2, 1026):
print("," + str(i), end="")
EOF
`
The command succeeds and shows following output.
service/temp-svc created
The service has been successfully generated and can also be referenced with the
get command.
$ kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S)
temp-svc NodePort 10.0.0.139 <none> 1:31335/TCP,2:32367/TCP,3:30263/TCP,(omitted),1023:31821/TCP,1024:32475/TCP,1025:30311/TCP 12s
The user does not recognize failure to assign a NodePort because
create/get/describe command does not show any error. This is the issue.
[solution]
Users can notice errors by looking at the kube-proxy logs, but it may be difficult to see the kube-proxy logs of all nodes.
E0327 08:50:10.216571 660960 proxier.go:1286] "can't open port, skipping this nodePort" err="listen tcp4 :30641: socket: too many open files" port="\"nodePort for default/temp-svc:744\" (:30641/tcp4)"
E0327 08:50:10.216611 660960 proxier.go:1286] "can't open port, skipping this nodePort" err="listen tcp4 :30827: socket: too many open files" port="\"nodePort for default/temp-svc:857\" (:30827/tcp4)"
...
E0327 08:50:10.217119 660960 proxier.go:1286] "can't open port, skipping this nodePort" err="listen tcp4 :32484: socket: too many open files" port="\"nodePort for default/temp-svc:805\" (:32484/tcp4)"
E0327 08:50:10.217293 660960 proxier.go:1612] "Failed to execute iptables-restore" err="pipe2: too many open files ()"
I0327 08:50:10.217341 660960 proxier.go:1615] "Closing local ports after iptables-restore failure"
So, this patch will fire an event when NodePort assignment fails.
In fact, when the externalIP assignment fails, it is also notified by event.
The event will be displayed like this.
$ kubectl get event
LAST SEEN TYPE REASON OBJECT MESSAGE
...
2s Warning listen tcp4 :31055: socket: too many open files node/127.0.0.1 can't open "nodePort for default/temp-svc:901" (:31055/tcp4), skipping this nodePort: listen tcp4 :31055: socket: too many open files
2s Warning listen tcp4 :31422: socket: too many open files node/127.0.0.1 can't open "nodePort for default/temp-svc:474" (:31422/tcp4), skipping this nodePort: listen tcp4 :31422: socket: too many open files
...
This PR fixes iptables and ipvs proxier.
Since userspace proxier does not seem to be affected by this issue, it is not fixed.
[1] Assume that fd limit is 1024(default).
$ ulimit -n
1024
1. Add API definitions;
2. Add feature gate and drops the field when feature gate is not on;
3. Set default values for the field;
4. Add API Validation
5. add kube-proxy iptables and ipvs implementations
6. add tests
Clear conntrack entries for UDP NodePorts,
this has to be done AFTER the iptables rules are programmed.
It can happen that traffic to the NodePort hits the host before
the iptables rules are programmed this will create an stale entry
in conntrack that will blackhole the traffic, so we need to
clear it ONLY when the service has endpoints.
1. For iptables mode, add KUBE-NODEPORTS chain in filter table. Add
rules to allow healthcheck node port traffic.
2. For ipvs mode, add KUBE-NODE-PORT chain in filter table. Add
KUBE-HEALTH-CHECK-NODE-PORT ipset to allow traffic to healthcheck
node port.
When running in ipvs mode, kube-proxy generated wrong iptables-restore
input because the chain names are hardcoded.
It also fixed a typo in method name.
Currently kube-proxy treat ExternalIPs differently depending on:
- the traffic origin
- if the ExternalIP is present or not in the system.
It also depends on the CNI implementation to
discriminate between local and non-local traffic.
Since the ExternalIP belongs to a Service, we can avoid the roundtrip
of sending outside the traffic originated in the cluster.
Also, we leverage the new LocalTrafficDetector to detect the local
traffic and not rely on the CNI implementations for this.
- Remove feature gate consideration from EndpointSlice validation
- Deprecate topology field, note that it will be removed in future
release
- Update kube-proxy to check for NodeName if feature gate is enabled
- Add comments indicating the feature gates that can be used to enable
alpha API fields
- Add comments explaining use of deprecated address type in tests
The tests for most functions have also been revised to check the errors
explicitly upon validating. This will properly catch occasions
where we should be returning multiple errors if more error occurs or
if just one block is failing.
Signed-off-by: Christopher M. Luciano <cmluciano@us.ibm.com>
This commit revises validateProxyNodePortAddress and
validateExcludeCIDRS to report on the exact CIDR that is
invalid within the array of strings. Previously we would just return
the whole block of addresses and now we identify the exact address
within the block to eliminate confusion. I also removed the break from
validateProxyNodeAddress so that we can report on all addresses that
may not be valid.
The tests for each function have also been revised to check the errors
explicitly upon validating. This also will properly catch occasions
where we should be returning multiple errors if more than one CIDR is invalid.
Signed-off-by: Christopher M. Luciano <cmluciano@us.ibm.com>
A previous PR (#71573) intended to clear conntrack entry on endpoint
changes when using nodeport by introducing a dedicated function to
remove the stale conntrack entry on the node port and allow traffic to
resume. By doing so, it has introduced a nodeport specific bug where the
conntrack entries related to the ClusterIP does not get clean if
endpoint is changed (issue #96174). We fix by doing ClusterIP cleanup in
all cases.
* api: structure change
* api: defaulting, conversion, and validation
* [FIX] validation: auto remove second ip/family when service changes to SingleStack
* [FIX] api: defaulting, conversion, and validation
* api-server: clusterIPs alloc, printers, storage and strategy
* [FIX] clusterIPs default on read
* alloc: auto remove second ip/family when service changes to SingleStack
* api-server: repair loop handling for clusterIPs
* api-server: force kubernetes default service into single stack
* api-server: tie dualstack feature flag with endpoint feature flag
* controller-manager: feature flag, endpoint, and endpointSlice controllers handling multi family service
* [FIX] controller-manager: feature flag, endpoint, and endpointSlicecontrollers handling multi family service
* kube-proxy: feature-flag, utils, proxier, and meta proxier
* [FIX] kubeproxy: call both proxier at the same time
* kubenet: remove forced pod IP sorting
* kubectl: modify describe to include ClusterIPs, IPFamilies, and IPFamilyPolicy
* e2e: fix tests that depends on IPFamily field AND add dual stack tests
* e2e: fix expected error message for ClusterIP immutability
* add integration tests for dualstack
the third phase of dual stack is a very complex change in the API,
basically it introduces Dual Stack services. Main changes are:
- It pluralizes the Service IPFamily field to IPFamilies,
and removes the singular field.
- It introduces a new field IPFamilyPolicyType that can take
3 values to express the "dual-stack(mad)ness" of the cluster:
SingleStack, PreferDualStack and RequireDualStack
- It pluralizes ClusterIP to ClusterIPs.
The goal is to add coverage to the services API operations,
taking into account the 6 different modes a cluster can have:
- single stack: IP4 or IPv6 (as of today)
- dual stack: IPv4 only, IPv6 only, IPv4 - IPv6, IPv6 - IPv4
* [FIX] add integration tests for dualstack
* generated data
* generated files
Co-authored-by: Antonio Ojea <aojea@redhat.com>
In #56164, we had split the reject rules for non-ep existing services
into KUBE-EXTERNAL-SERVICES chain in order to avoid calling KUBE-SERVICES
from INPUT. However in #74394 KUBE-SERVICES was re-added into INPUT.
As noted in #56164, kernel is sensitive to the size of INPUT chain. This
patch refrains from calling the KUBE-SERVICES chain from INPUT and FORWARD,
instead adds the lb reject rule to the KUBE-EXTERNAL-SERVICES chain which will be
called from INPUT and FORWARD.
The provided DialContext wraps existing clients' DialContext in an attempt to
preserve any existing timeout configuration. In some cases, we may replace
infinite timeouts with golang defaults.
- scaleio: tcp connect/keepalive values changed from 0/15 to 30/30
- storageos: no change
Before this fix, a Service with a loadBalancerSourceRange value that
included a space would cause kube-proxy to crashloop. This updates
kube-proxy to trim any space from that field.
Currently kube-proxy defaults the min-sync-period for
iptables to 0. However, as explained by Dan Winship,
"With minSyncPeriod: 0, you run iptables-restore 100 times.
With minSyncPeriod: 1s , you run iptables-restore once.
With minSyncPeriod: 10s , you also run iptables-restore once,
but you might have to wait 10 seconds first"
Masquerade de traffic that loops back to the originator
before they hit the kubernetes-specific postrouting rules
Signed-off-by: Antonio Ojea <antonio.ojea.garcia@gmail.com>
when dual-stack kube-proxy infers the service IP family from
the ClusterIP because ipFamily field is going to be deprecated.
Since kube-proxy skip headless and externalname services we
can safely obtain the IPFamily from the ClusterIP field
Signed-off-by: Antonio Ojea <antonio.ojea.garcia@gmail.com>
instead of receiving the service name and namespace we
can obtain it from the service object directly.
Signed-off-by: Antonio Ojea <antonio.ojea.garcia@gmail.com>
It seems that if you set the packet mark on a packet and then route
that packet through a kernel VXLAN interface, the VXLAN-encapsulated
packet will still have the mark from the original packet. Since our
NAT rules are based on the packet mark, this was causing us to
double-NAT some packets, which then triggered a kernel checksumming
bug. But even without the checksum bug, there are reasons to avoid
double-NATting, so fix the rules to unmark the packets before
masquerading them.
Fixes two small issues with the metric added in #90175:
1. Bump the timestamp on initial informer sync. Otherwise it remains 0 if
restarting kube-proxy in a quiescent cluster, which isn't quite right.
2. Bump the timestamp even if no healthz server is specified.
This adds a metric, kubeproxy_sync_proxy_rules_last_queued_timestamp,
that captures the last time a change was queued to be applied to the
proxy. This matches the healthz logic, which fails if a pending change
is stale.
This allows us to write alerts that mirror healthz.
Signed-off-by: Casey Callendrello <cdc@redhat.com>
This builds on previous work but only sets the sysctlConnReuse value
if the kernel is known to be above 4.19. To avoid calling GetKernelVersion
twice, I store the value from the CanUseIPVS method and then check the version
constraint at time of expected sysctl call.
Signed-off-by: Christopher M. Luciano <cmluciano@us.ibm.com>
The kube-proxy metaproxier implementations tries to get the IPFamily
from the endpoints, but if the endpoints doesn't contains an IP
address it logs a Warning.
This causes that services without endpoints keep flooding the logs
with warnings.
We log this errors with a level of Verbosity of 4 instead of a Warning
This allows the proxier to cache local addresses instead of fetching all
local addresses every time in IsLocalIP.
Signed-off-by: Andrew Sy Kim <kiman@vmware.com>
This avoids fetching all local network interfaces everytime we sync an
external IP. For clusters with many external IPs this gets really
expensive. This change caches all local addresses once per sync.
Signed-off-by: Andrew Sy Kim <kiman@vmware.com>
This avoids fetching all local network interfaces everytime we sync an
external IP. For clusters with many external IPs this gets really
expensive. This change caches all local addresses once per sync.
Signed-off-by: Andrew Sy Kim <kiman@vmware.com>
kube-proxy, if is configured with an IP family, filters out the
incorrect IP version of the services.
This commit fix a bug caused by not filtering out the IPs in the
LoadBalancer Status Ingress field.
kube-proxy was not validating correctly the clusterCIDRs, if
dual-stack it MAY have 1 or more clusterCIDRs. If it has 2 cidrs and
at least one of each IP family.
It also fixes a bug where validation was not taking into account
the feature gates global state.
This creates a new EndpointSliceProxying feature gate to cover EndpointSlice
consumption (kube-proxy) and allow the existing EndpointSlice feature gate to
focus on EndpointSlice production only. Along with that addition, this enables
the EndpointSlice feature gate by default, now only affecting the controller.
The rationale here is that it's really difficult to guarantee all EndpointSlices
are created in a cluster upgrade process before kube-proxy attempts to consume
them. Although masters are generally upgraded before nodes, and in most cases,
the controller would have enough time to create EndpointSlices before a new node
with kube-proxy spun up, there are plenty of edge cases where that might not be
the case. The primary limitation on EndpointSlice creation is the API rate limit
of 20QPS. In clusters with a lot of endpoints and/or with a lot of other API
requests, it could be difficult to create all the EndpointSlices before a new
node with kube-proxy targeting EndpointSlices spun up.
Separating this into 2 feature gates allows for a more gradual rollout with the
EndpointSlice controller being enabled by default in 1.18, and EndpointSlices
for kube-proxy being enabled by default in the next release.
