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Merge pull request #37464 from windsonsea/seren 

Fix inconsistencies in service.md
pull/37819/head
Kubernetes Prow Robot 2022-11-09 14:06:54 -08:00 committed by GitHub
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content/en/docs/concepts/services-networking/service.md
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@ -145,7 +145,6 @@ spec:
targetPort: http-web-svc targetPort: http-web-svc
``` ```
This works even if there is a mixture of Pods in the Service using a single This works even if there is a mixture of Pods in the Service using a single
configured name, with the same network protocol available via different configured name, with the same network protocol available via different
port numbers. This offers a lot of flexibility for deploying and evolving port numbers. This offers a lot of flexibility for deploying and evolving
@ -353,7 +352,7 @@ thus is only available to use as-is.
Note that the kube-proxy starts up in different modes, which are determined by its configuration. Note that the kube-proxy starts up in different modes, which are determined by its configuration.
- The kube-proxy's configuration is done via a ConfigMap, and the ConfigMap for kube-proxy - The kube-proxy's configuration is done via a ConfigMap, and the ConfigMap for kube-proxy
effectively deprecates the behaviour for almost all of the flags for the kube-proxy. effectively deprecates the behavior for almost all of the flags for the kube-proxy.
- The ConfigMap for the kube-proxy does not support live reloading of configuration. - The ConfigMap for the kube-proxy does not support live reloading of configuration.
- The ConfigMap parameters for the kube-proxy cannot all be validated and verified on startup. - The ConfigMap parameters for the kube-proxy cannot all be validated and verified on startup.
For example, if your operating system doesn't allow you to run iptables commands, For example, if your operating system doesn't allow you to run iptables commands,
@ -420,7 +419,7 @@ The IPVS proxy mode is based on netfilter hook function that is similar to
iptables mode, but uses a hash table as the underlying data structure and works iptables mode, but uses a hash table as the underlying data structure and works
in the kernel space. in the kernel space.
That means kube-proxy in IPVS mode redirects traffic with lower latency than That means kube-proxy in IPVS mode redirects traffic with lower latency than
kube-proxy in iptables mode, with much better performance when synchronising kube-proxy in iptables mode, with much better performance when synchronizing
proxy rules. Compared to the other proxy modes, IPVS mode also supports a proxy rules. Compared to the other proxy modes, IPVS mode also supports a
higher throughput of network traffic. higher throughput of network traffic.
@ -662,7 +661,8 @@ Kubernetes `ServiceTypes` allow you to specify what kind of Service you want.
* [`ExternalName`](#externalname): Maps the Service to the contents of the * [`ExternalName`](#externalname): Maps the Service to the contents of the
`externalName` field (e.g. `foo.bar.example.com`), by returning a `CNAME` record `externalName` field (e.g. `foo.bar.example.com`), by returning a `CNAME` record
with its value. No proxying of any kind is set up. with its value. No proxying of any kind is set up.
{{< note >}}You need either `kube-dns` version 1.7 or CoreDNS version 0.0.8 or higher {{< note >}}
You need either `kube-dns` version 1.7 or CoreDNS version 0.0.8 or higher
to use the `ExternalName` type. to use the `ExternalName` type.
{{< /note >}} {{< /note >}}
@ -740,11 +740,11 @@ kube-proxy only selects the loopback interface for NodePort Services.
The default for `--nodeport-addresses` is an empty list. The default for `--nodeport-addresses` is an empty list.
This means that kube-proxy should consider all available network interfaces for NodePort. This means that kube-proxy should consider all available network interfaces for NodePort.
(That's also compatible with earlier Kubernetes releases.) (That's also compatible with earlier Kubernetes releases.)
Note that this Service is visible as `<NodeIP>:spec.ports[*].nodePort` {{< note >}}
and `.spec.clusterIP:spec.ports[*].port`. This Service is visible as `<NodeIP>:spec.ports[*].nodePort` and `.spec.clusterIP:spec.ports[*].port`.
If the `--nodeport-addresses` flag for kube-proxy or the equivalent field If the `--nodeport-addresses` flag for kube-proxy or the equivalent field
in the kube-proxy configuration file is set, `<NodeIP>` would be a filtered node IP address (or possibly IP addresses). in the kube-proxy configuration file is set, `<NodeIP>` would be a filtered node IP address (or possibly IP addresses).
{{< /note >}}
### Type LoadBalancer {#loadbalancer} ### Type LoadBalancer {#loadbalancer}
@ -793,7 +793,6 @@ _As an alpha feature_, you can configure a load balanced Service to
[omit](#load-balancer-nodeport-allocation) assigning a node port, provided that the [omit](#load-balancer-nodeport-allocation) assigning a node port, provided that the
cloud provider implementation supports this. cloud provider implementation supports this.
{{< note >}} {{< note >}}
On **Azure**, if you want to use a user-specified public type `loadBalancerIP`, you first need On **Azure**, if you want to use a user-specified public type `loadBalancerIP`, you first need
@ -1400,7 +1399,7 @@ fail with a message indicating an IP address could not be allocated.
In the control plane, a background controller is responsible for creating that In the control plane, a background controller is responsible for creating that
map (needed to support migrating from older versions of Kubernetes that used map (needed to support migrating from older versions of Kubernetes that used
in-memory locking). Kubernetes also uses controllers to check for invalid in-memory locking). Kubernetes also uses controllers to check for invalid
assignments (eg due to administrator intervention) and for cleaning up allocated assignments (e.g. due to administrator intervention) and for cleaning up allocated
IP addresses that are no longer used by any Services. IP addresses that are no longer used by any Services.
#### IP address ranges for `type: ClusterIP` Services {#service-ip-static-sub-range} #### IP address ranges for `type: ClusterIP` Services {#service-ip-static-sub-range}
@ -1476,7 +1475,7 @@ through a load-balancer, though in those cases the client IP does get altered.
#### IPVS #### IPVS
iptables operations slow down dramatically in large scale cluster e.g 10,000 Services. iptables operations slow down dramatically in large scale cluster e.g. 10,000 Services.
IPVS is designed for load balancing and based on in-kernel hash tables. IPVS is designed for load balancing and based on in-kernel hash tables.
So you can achieve performance consistency in large number of Services from IPVS-based kube-proxy. So you can achieve performance consistency in large number of Services from IPVS-based kube-proxy.
Meanwhile, IPVS-based kube-proxy has more sophisticated load balancing algorithms Meanwhile, IPVS-based kube-proxy has more sophisticated load balancing algorithms