Change:
This is a Feature Request translate /docs/concepts/services-networking/topology-aware- into Chinese What would you like to be /zh/docs/concepts/services-networking/topology-aware-
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<ins> --- title: 拓扑感知提示 content_type: concept weight: 45 --- <!-- --- reviewers: - robscott title: Topology Aware Hints content_type: concept weight: 45 --- --> <!-- overview --> {{< feature-state for_k8s_version="v1.21" state="alpha" >}} <!-- _Topology Aware Hints_ enable topology aware routing by including suggestions for how clients should consume endpoints. This approach adds metadata to enable consumers of EndpointSlice and / or and Endpoints objects, so that traffic to those network endpoints can be routed closer to where it originated. For example, you can route traffic within a locality to reduce costs, or to improve network performance. --> _拓扑感知提示_ 包含客户怎么使用服务端点的建议，从而实现了拓扑感知的路由功能。 这种方法添加了元数据，以启用 EndpointSlice 和/或 Endpoints 对象的调用者， 这样，访问这些网络端点的请求流量就可以在它的发起点附近就近路由。 例如，你可以在一个地域内路由流量，以降低通信成本，或提高网络性能。 <!-- body --> <!-- ## Motivation --> ## 动机 {#motivation} <!-- Kubernetes clusters are increasingly deployed in multi-zone environments. _Topology Aware Hints_ provides a mechanism to help keep traffic within the zone it originated from. This concept is commonly referred to as "Topology Aware Routing". When calculating the endpoints for a {{< glossary_tooltip term_id="Service" >}}, the EndpointSlice controller considers the topology (region and zone) of each endpoint and populates the hints field to allocate it to a zone. Cluster components such as the {{< glossary_tooltip term_id="kube-proxy" text="kube-proxy" >}} can then consume those hints, and use them to influence how traffic to is routed (favoring topologically closer endpoints). --> Kubernetes 集群越来越多的部署到多区域环境中。 _拓扑感知提示_ 提供了一种把流量限制在它的发起区域之内的机制。 这个概念一般被称之为 “拓扑感知路由”。 在计算 {{< glossary_tooltip term_id="Service" >}} 的端点时， EndpointSlice 控制器会评估每一个端点的拓扑（地域和区域），填充提示字段，并将其分配到某个区域。 集群组件，例如{{< glossary_tooltip term_id="kube-proxy" text="kube-proxy" >}} 就可以使用这些提示信息，并用他们来影响流量的路由（倾向于拓扑上相邻的端点）。 <!-- ## Using Topology Aware Hints --> ## 使用拓扑感知提示 {#using-topology-aware-hints} <!-- If you have [enabled](/docs/tasks/administer-cluster/enabling-topology-aware-hints) the overall feature, you can activate Topology Aware Hints for a Service by setting the `service.kubernetes.io/topology-aware-hints` annotation to `auto`. This tells the EndpointSlice controller to set topology hints if it is deemed safe. Importantly, this does not guarantee that hints will always be set. --> 如果你已经[启用](/zh/docs/tasks/administer-cluster/enabling-topology-aware-hints)了整个特性， 就可以通过把注解 `service.kubernetes.io/topology-aware-hints` 的值设置为 `auto`， 来激活服务的拓扑感知提示功能。 这告诉 EndpointSlice 控制器在它认为安全的时候来设置拓扑提示。 重要的是，这并不能保证总会设置提示（hints）。 <!-- ## How it works {#implementation} --> ## 工作原理 {#implementation} <!-- The functionality enabling this feature is split into two components: The EndpointSlice controller and the kube-proxy. This section provides a high level overview of how each component implements this feature. --> 此特性启用的功能分为两个组件：EndpointSlice 控制器和 kube-proxy。 本节概述每个组件如何实现此特性。 <!-- ### EndpointSlice controller {#implementation-control-plane} --> ### EndpointSlice 控制器 {#implementation-control-plane} <!-- The EndpointSlice controller is responsible for setting hints on EndpointSlices when this feature is enabled. The controller allocates a proportional amount of endpoints to each zone. This proportion is based on the [allocatable](/docs/tasks/administer-cluster/reserve-compute-resources/#node-allocatable) CPU cores for nodes running in that zone. For example, if one zone had 2 CPU cores and another zone only had 1 CPU core, the controller would allocated twice as many endpoints to the zone with 2 CPU cores. --> 此特性开启后，EndpointSlice 控制器负责在 EndpointSlice 上设置提示信息。 控制器按比例给每个区域分配一定比例数量的端点。 这个比例来源于此区域中运行节点的 [可分配](/zh/docs/tasks/administer-cluster/reserve-compute-resources/#node-allocatable) CPU 核心数。 例如，如果一个区域拥有 2 CPU 核心，而另一个区域只有 1 CPU 核心， 那控制器将给那个有 2 CPU 的区域分配两倍数量的端点。 <!-- The following example shows what an EndpointSlice looks like when hints have been populated: --> 以下示例展示了提供提示信息后 EndpointSlice 的样子： ```yaml apiVersion: discovery.k8s.io/v1 kind: EndpointSlice metadata: name: example-hints labels: kubernetes.io/service-name: example-svc addressType: IPv4 ports: - name: http protocol: TCP port: 80 endpoints: - addresses: - "10.1.2.3" conditions: ready: true hostname: pod-1 zone: zone-a hints: forZones: - name: "zone-a" ``` ### kube-proxy {#implementation-kube-proxy} <!-- The kube-proxy component filters the endpoints it routes to based on the hints set by the EndpointSlice controller. In most cases, this means that the kube-proxy is able to route traffic to endpoints in the same zone. Sometimes the controller allocates endpoints from a different zone to ensure more even distribution of endpoints between zones. This would result in some traffic being routed to other zones. --> kube-proxy 组件依据 EndpointSlice 控制器设置的提示，过滤由它负责路由的端点。 在大多数场合，这意味着 kube-proxy 可以把流量路由到同一个区域的端点。 有时，控制器从某个不同的区域分配端点，以确保在多个区域之间更平均的分配端点。 这会导致部分流量被路由到其他区域。 <!-- ## Safeguards --> ## 保护措施 {#safeguards} <!-- The Kubernetes control plane and the kube-proxy on each node apply some safeguard rules before using Topology Aware Hints. If these don't check out, the kube-proxy selects endpoints from anywhere in your cluster, regardless of the zone. --> Kubernetes 控制平面和每个节点上的 kube-proxy，在使用拓扑感知提示功能前，会应用一些保护措施规则。 如果没有检出，kube-proxy 将无视区域限制，从集群中的任意节点上选择端点。 <!-- 1. **Insufficient number of endpoints:** If there are less endpoints than zones in a cluster, the controller will not assign any hints. --> 1. **端点数量不足：** 如果一个集群中，端点数量少于区域数量，控制器不创建任何提示。 <!-- 2. **Impossible to achieve balanced allocation:** In some cases, it will be impossible to achieve a balanced allocation of endpoints among zones. For example, if zone-a is twice as large as zone-b, but there are only 2 endpoints, an endpoint allocated to zone-a may receive twice as much traffic as zone-b. The controller does not assign hints if it can't get this "expected overload" value below an acceptable threshold for each zone. Importantly this is not based on real-time feedback. It is still possible for individual endpoints to become overloaded. --> 2. **不可能实现均衡分配：** 在一些场合中，不可能实现端点在区域中的平衡分配。 例如，假设 zone-a 比 zone-b 大两倍，但只有 2 个端点， 那分配到 zone-a 的端点可能收到比 zone-b多两倍的流量。 如果控制器不能确定此“期望的过载”值低于每一个区域可接受的阈值，控制器将不指派提示信息。 重要的是，这不是基于实时反馈。所以对于单独的端点仍有可能超载。 <!-- 3. **One or more Nodes has insufficient information:** If any node does not have a `topology.kubernetes.io/zone` label or is not reporting a value for allocatable CPU, the control plane does not set any topology-aware endpoint hints and so kube-proxy does not filter endpoints by zone. --> 3. **一个或多个节点信息不足：** 如果任一节点没有设置标签 `topology.kubernetes.io/zone`， 或没有上报可分配的 CPU 数据，控制平面将不会设置任何拓扑感知提示， 继而 kube-proxy 也就不能通过区域过滤端点。 <!-- 4. **One or more endpoints does not have a zone hint:** When this happens, the kube-proxy assumes that a transition from or to Topology Aware Hints is underway. Filtering endpoints for a Service in this state would be dangerous so the kube-proxy falls back to using all endpoints. --> 4. **一个或多个端点没有设置区域提示：** 当这类事情发生时， kube-proxy 会假设这是正在执行一个从/到拓扑感知提示的转移。 在这种场合下过滤Service 的端点是有风险的，所以 kube-proxy 回撤为使用所有的端点。 <!-- 5. **A zone is not represented in hints:** If the kube-proxy is unable to find at least one endpoint with a hint targeting the zone it is running in, it falls to using endpoints from all zones. This is most likely to happen as you add a new zone into your existing cluster. --> 5. **不在提示中的区域：** 如果 kube-proxy 不能根据一个指示在它所在的区域中发现一个端点， 它回撤为使用所有节点的端点。当你的集群新增一个新的区域时，这种情况发生概率很高。 <!-- ## Constraints --> ## 限制 {#constraints} <!-- * Topology Aware Hints are not used when either `externalTrafficPolicy` or `internalTrafficPolicy` is set to `Local` on a Service. It is possible to use both features in the same cluster on different Services, just not on the same Service. --> * 当 Service 的 `externalTrafficPolicy` 或 `internalTrafficPolicy` 设置值为 `Local` 时， 拓扑感知提示功能不可用。 你可以在一个集群的不同服务中使用这两个特性，但不能在同一个服务中这么做。 <!-- * This approach will not work well for Services that have a large proportion of traffic originating from a subset of zones. Instead this assumes that incoming traffic will be roughly proportional to the capacity of the Nodes in each zone. --> * 这种方法不适用于大部分流量来自于一部分区域的服务。 相反的，这里假设入站流量将根据每个区域中节点的服务能力按比例的分配。 <!-- * The EndpointSlice controller ignores unready nodes as it calculates the proportions of each zone. This could have unintended consequences if a large portion of nodes are unready. --> * EndpointSlice 控制器在计算每一个区域的容量比例时，会忽略未就绪的节点。 在大量节点未就绪的场景下，这样做会带来非预期的结果。 <!-- * The EndpointSlice controller does not take into account {{< glossary_tooltip text="tolerations" term_id="toleration" >}} when deploying calculating the proportions of each zone. If the Pods backing a Service are limited to a subset of Nodes in the cluster, this will not be taken into account. --> * EndpointSlice 控制器在计算每一个区域的部署比例时，并不会考虑 {{< glossary_tooltip text="容忍度" term_id="toleration" >}}。 如果服务后台的 Pod 被限制只能运行在集群节点的一个子集上，这些信息并不会被使用。 <!-- * This may not work well with autoscaling. For example, if a lot of traffic is originating from a single zone, only the endpoints allocated to that zone will be handling that traffic. That could result in {{< glossary_tooltip text="Horizontal Pod Autoscaler" term_id="horizontal-pod-autoscaler" >}} either not picking up on this event, or newly added pods starting in a different zone. --> * 这种方法和自动扩展机制之间不能很好的协同工作。例如，如果大量流量来源于一个区域， 那只有分配到该区域的端点才可用来处理流量。这会导致 {{< glossary_tooltip text="Pod 自动水平扩展" term_id="horizontal-pod-autoscaler" >}} 要么不能拾取此事件，要么新增 Pod 被启动到其他区域。 ## {{% heading "whatsnext" %}} <!-- * Read about [enabling Topology Aware Hints](/docs/tasks/administer-cluster/enabling-topology-aware-hints/) * Read [Connecting Applications with Services](/docs/concepts/services-networking/connect-applications-service/) --> * 参阅[启用拓扑感知提示](/zh/docs/tasks/administer-cluster/enabling-topology-aware-hints/) * 参阅[通过服务连通应用](/zh/docs/concepts/services-networking/connect-applications-service/) </ins>