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Only run connection-rejecting rules on new connections
Kube-proxy has two iptables chains full of rules to reject incoming connections to services that don't have any endpoints. Currently these rules get tested against all incoming packets, but that's unnecessary; if a connection to a given service has already been established, then we can't have been rejecting connections to that service. By only checking the first packet in each new connection, we can get rid of a lot of unnecessary checks on incoming traffic.
Fixes#56842
**Release note**:
```release-note
Additional changes to iptables kube-proxy backend to improve performance on clusters with very large numbers of services.
```
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Delete stale UDP conntrack entries that use hostPort
**What this PR does / why we need it**:
This PR introduces a change to delete stale conntrack entries for UDP connections, specifically for udp connections that use hostPort. When the pod listening on that udp port get updated/restarted(and gets a new ip address), these entries need to be flushed so that ongoing udp connections can recover once the pod is back and the new iptables rules have been installed.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes#59033
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
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Don't create no-op iptables rules for services with no endpoints
Currently for all services we create `-t nat -A KUBE-SERVICES` rules that match the destination IPs (ClusterIP, ExternalIP, NodePort IPs, etc) and then jump to the appropriate `KUBE-SVC-XXXXXX` chain. But if the service has no endpoints then the `KUBE-SVC-XXXXXX` chain will be empty and so nothing happens except that we wasted time (a) forcing iptables-restore to parse the match rules, and (b) forcing the kernel to test matches that aren't going to have any effect.
This PR gets rid of the match rules in this case. Which is to say, it changes things so that every incoming service packet is matched *either* by nat rules to rewrite it *or* by filter rules to ICMP reject it, but not both. (Actually, that's not quite true: there are no filter rules to reject Ingress-addressed packets, and I *think* that's a bug?)
I also got rid of some comments that seemed redundant.
The patch is mostly reindentation, so best viewed with `diff -w`.
Partial fix for #56842 / Related to #56164 (which it conflicts with but I'll fix that after one or the other merges).
**Release note**:
```release-note
Removed some redundant rules created by the iptables proxier, to improve performance on systems with very many services.
```
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Split KUBE-SERVICES chain to re-shrink the INPUT chain
**What this PR does / why we need it**:
#43972 added an iptables rule "`-A INPUT -j KUBE-SERVICES`" to make NodePort ICMP rejection work. (Previously the KUBE-SERVICES chain was only run from OUTPUT, not INPUT.) #44547 extended that patch for ExternalIP rejection as well.
However, the KUBE-SERVICES chain may potentially have a very large number of ICMP reject rules for plain ClusterIP services (the ones that get run from OUTPUT), and it seems that for some reason the kernel is much more sensitive to the length of the INPUT chain than it is to the length of the OUTPUT chain. So a node that worked fine with kube 1.6 (when KUBE-SERVICES was only run from OUTPUT) might fall over with kube 1.7 (with KUBE-SERVICES being run from both INPUT and OUTPUT).
(Specifically, a node with about 5000 ClusterIP reject rules that ran fine with OpenShift 3.6 [kube 1.6] slowed almost to a complete halt with OpenShift 3.7 [kube 1.7].)
This PR fixes things by splitting out the "new" part of KUBE-SERVICES (NodePort and ExternalIP reject rules) into a separate KUBE-EXTERNAL-SERVICES chain run from INPUT, and moves KUBE-SERVICES back to being only run from OUTPUT. (So, yes, this assumes that you don't have 5000 NodePort/ExternalIP services, but, if you do, there's not much we can do, since those rules *have* to be run on the INPUT side.)
Oh, and I left in the code to clean up the "`-A INPUT -j KUBE-SERVICES`" rule even though we don't generate it any more, so it gets fixed on upgrade.
**Release note**:
```release-note
Reorganized iptables rules to fix a performance regression on clusters with thousands of services.
```
@kubernetes/sig-network-bugs @kubernetes/rh-networking
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Refactor kube-proxy service/endpoints update so that can be consumed among different proxiers
**What this PR does / why we need it**:
There are huge duplication among different proxiers. For example, the service/endpoints list/watch part in iptables, ipvs and windows kernel mode(to be get in soon).
I think the more places this is replicated the harder it becomes to keep correct. We may need to refactor it and let different proxiers consume the same code.
**Which issue this PR fixes**:
fixes#52464
**Special notes for your reviewer**:
* This refactor reduces **500** Lines in iptables proxy, so it will reduce **500*N**(number of proxiers) lines in total. People no need to care the service/endpoints update logic any more and can be more focus on proxy logic.
* I would like to do the following things in follow-ups:
1. rsync it to ipvs proxier
2. rsync it to winkernel proxier
**Release note**:
```release-note
Refactor kube-proxy service/endpoints update so that can be consumed among different proxiers
```
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Abstract some duplicated code in the iptables proxier
Reorganizes the iptables proxier code so we only have the list of "-A FOO -j KUBE-BAR" rules in one place rather than duplicating the same list in multiple places. Split out from #56164 for ease of review/merging.
**Release note**:
```release-note
NONE
```
Automatic merge from submit-queue (batch tested with PRs 58300, 58530, 57942, 58543). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Fix nodeport localhost martian source error
**What this PR does / why we need it**:
kube-proxy NodePort access via localhost, with externalTrafficPolicy=Local will trigger martian source error.
This PR fixes nodeport localhost martian source error.
**Which issue(s) this PR fixes**:
Fixes#57922
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
Automatic merge from submit-queue (batch tested with PRs 53780, 55663, 55321, 52421, 55659). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Validate kube-proxy options
**What this PR does / why we need it**:
Validate ipvs proxy options
**Which issue this PR fixes** : fixes#53852
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
Automatic merge from submit-queue (batch tested with PRs 55009, 55532, 55601, 52569, 55533). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Kube-proxy adds forward rules to ensure NodePorts work
**What this PR does / why we need it**:
Updates kube-proxy to set up proper forwarding so that NodePorts work with docker 1.13 without depending on iptables FORWARD being changed manually/externally.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes#39823
**Special notes for your reviewer**:
@thockin I used option number 2 that I mentioned in the #39823 issue, please let me know what you think about this change. If you are happy with the change then I can try to add tests but may need a little direction about what and where to add them.
**Release note**:
```release-note
Add iptables rules to allow Pod traffic even when default iptables policy is to reject.
```
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Fix ipvs/proxy getLocalIPs inconsistency with iptables/proxy
**What this PR does / why we need it**:
* Fix ipvs/proxy `getLocalIPs()` inconsistency with iptables/proxy
* validate the ip address before pkg/proxy/util IPPart() return ip string.
**Which issue(s) this PR fixes** :
Fixes#55612
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
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Replace sets.List() with sets.UnsortedList() in pkg/proxy
**What this PR does / why we need it**:
Replace sets.List() with sets.UnsortedList() in pkg/proxy - sets.List() will sort the result array, we don't need sorted array in pkg/proxy. Using sets.UnsortedList() can reduce the unnecessary overhead spending.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #
**Special notes for your reviewer**:
@wojtek-t wdyt ^_^
**Release note**:
```release-note
NONE
```
/sig network
Don't log the set of rules at v2 in kube-proxy on error.
The rules are displayed at v5 before the restore is attempted.
In a large cluster the report can generate up to 100000 lines.
A partial report is only helpful if the problem is displayed
in the partial report.
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Add required family flag for conntrack IPv6 operation
This change causes kube-proxy to supply the required "-f ipv6"
family flag whenever the conntrack utility is executed and the
associated service is using IPv6.
This change is required for IPv6-only operation.
Note that unit test coverage for the 2-line changes in
pkg/proxy/iptables/proxier.go and /pkg/proxy/ipvs/proxier.go will need
to be added after support for IPv6 service addresses is added to these
files. For pkg/proxy/iptables/proxier.go, this coverage will be added
either with PR #48551.
fixes#52027
**What this PR does / why we need it**:
Kube-proxy is currently not supplying the required "-f ipv6" family flag whenever it
calls the conntrack utility and the associated service is using an IPv6 service IP address.
This means that for IPv6-only operation, conntrack is not properly cleaning up
stale UDP connections, and this may be effecting ip6tables operation.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes # 52027
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
The following changes are proposed for the iptables proxier:
* There are three places where a string specifying IP:port is parsed
using something like this:
if index := strings.Index(e.endpoint, ":"); index != -1 {
This will fail for IPv6 since V6 addresses contain colons. Also,
the V6 address is expected to be surrounded by square brackets
(i.e. []:). Fix this by replacing call to Index with
call to LastIndex() and stripping out square brackets.
* The String() method for the localPort struct should put square brackets
around IPv6 addresses.
* The logging in the merge() method for proxyServiceMap should put brackets
around IPv6 addresses.
* There are several places where filterRules destination is hardcoded to
/32. This should be a /128 for IPv6 case.
* Add IPv6 unit test cases
fixes#48550
This change causes kube-proxy to supply the required "-f ipv6"
family flag whenever the conntrack utility is executed and the
associated service is using IPv6.
This change is required for IPv6-only operation.
Note that unit test coverage for the 2-line changes in
pkg/proxy/iptables/proxier.go and /pkg/proxy/ipvs/proxier.go will need
to be added after support for IPv6 service addresses is added to these
files. For pkg/proxy/iptables/proxier.go, this coverage will be added
either with PR #48551.
fixes#52027
Automatic merge from submit-queue (batch tested with PRs 49850, 47782, 50595, 50730, 51341)
Paramaterize `stickyMaxAgeMinutes` for service in API
**What this PR does / why we need it**:
Currently I find `stickyMaxAgeMinutes` for a session affinity type service is hard code to 180min. There is a TODO comment, see
https://github.com/kubernetes/kubernetes/blob/master/pkg/proxy/iptables/proxier.go#L205
I think the seesion sticky max time varies from service to service and users may not aware of it since it's hard coded in all proxier.go - iptables, userspace and winuserspace.
Once we parameterize it in API, users can set/get the values for their different services.
Perhaps, we can introduce a new field `api.ClientIPAffinityConfig` in `api.ServiceSpec`.
There is an initial discussion about it in sig-network group. See,
https://groups.google.com/forum/#!topic/kubernetes-sig-network/i-LkeHrjs80
**Which issue this PR fixes**:
fixes#49831
**Special notes for your reviewer**:
**Release note**:
```release-note
Paramaterize session affinity timeout seconds in service API for Client IP based session affinity.
```
Automatic merge from submit-queue
Log abridged set of rules at v2 in kube-proxy on error
**What this PR does / why we need it**:
this is a follow-on to https://github.com/kubernetes/kubernetes/pull/48085
**Special notes for your reviewer**:
we hit this in operations where we typically run in v2, and would like to log abridged set of output rather than full output.
**Release note**:
```release-note
NONE
```
Zihong Zheng