From 85c8fd8e1f33ddd1dbf7e1671723338bb5318f61 Mon Sep 17 00:00:00 2001 From: Bradley Weston Date: Fri, 29 May 2020 10:28:47 +0100 Subject: [PATCH] feat: turn nodelocaldns image to svg --- .../tasks/administer-cluster/nodelocaldns.md | 34 +++++++++--------- .../tasks/administer-cluster/nodelocaldns.md | 8 ++--- static/images/docs/nodelocaldns.jpg | Bin 37691 -> 0 bytes static/images/docs/nodelocaldns.svg | 3 ++ 4 files changed, 24 insertions(+), 21 deletions(-) delete mode 100644 static/images/docs/nodelocaldns.jpg create mode 100644 static/images/docs/nodelocaldns.svg diff --git a/content/en/docs/tasks/administer-cluster/nodelocaldns.md b/content/en/docs/tasks/administer-cluster/nodelocaldns.md index 0907f8f0ac..cb033f2925 100644 --- a/content/en/docs/tasks/administer-cluster/nodelocaldns.md +++ b/content/en/docs/tasks/administer-cluster/nodelocaldns.md @@ -6,7 +6,7 @@ reviewers: title: Using NodeLocal DNSCache in Kubernetes clusters content_template: templates/task --- - + {{% capture overview %}} {{< feature-state for_k8s_version="v1.18" state="stable" >}} This page provides an overview of NodeLocal DNSCache feature in Kubernetes. @@ -27,7 +27,7 @@ NodeLocal DNSCache improves Cluster DNS performance by running a dns caching age ## Motivation -* With the current DNS architecture, it is possible that Pods with the highest DNS QPS have to reach out to a different node, if there is no local kube-dns/CoreDNS instance. +* With the current DNS architecture, it is possible that Pods with the highest DNS QPS have to reach out to a different node, if there is no local kube-dns/CoreDNS instance. Having a local cache will help improve the latency in such scenarios. * Skipping iptables DNAT and connection tracking will help reduce [conntrack races](https://github.com/kubernetes/kubernetes/issues/56903) and avoid UDP DNS entries filling up conntrack table. @@ -45,7 +45,7 @@ Having a local cache will help improve the latency in such scenarios. This is the path followed by DNS Queries after NodeLocal DNSCache is enabled: -{{< figure src="/images/docs/nodelocaldns.jpg" alt="NodeLocal DNSCache flow" title="Nodelocal DNSCache flow" caption="This image shows how NodeLocal DNSCache handles DNS queries." >}} +{{< figure src="/images/docs/nodelocaldns.svg" alt="NodeLocal DNSCache flow" title="Nodelocal DNSCache flow" caption="This image shows how NodeLocal DNSCache handles DNS queries." >}} ## Configuration {{< note >}} The local listen IP address for NodeLocal DNSCache can be any IP in the 169.254.20.0/16 space or any other IP address that can be guaranteed to not collide with any existing IP. This document uses 169.254.20.10 as an example. @@ -54,33 +54,33 @@ This is the path followed by DNS Queries after NodeLocal DNSCache is enabled: This feature can be enabled using the following steps: * Prepare a manifest similar to the sample [`nodelocaldns.yaml`](https://github.com/kubernetes/kubernetes/blob/master/cluster/addons/dns/nodelocaldns/nodelocaldns.yaml) and save it as `nodelocaldns.yaml.` -* Substitute the variables in the manifest with the right values: +* Substitute the variables in the manifest with the right values: + + * kubedns=`kubectl get svc kube-dns -n kube-system -o jsonpath={.spec.clusterIP}` + + * domain=`` - * kubedns=`kubectl get svc kube-dns -n kube-system -o jsonpath={.spec.clusterIP}` - - * domain=`` - * localdns=`` - + `` is "cluster.local" by default. `` is the local listen IP address chosen for NodeLocal DNSCache. - * If kube-proxy is running in IPTABLES mode: - + * If kube-proxy is running in IPTABLES mode: + ``` bash sed -i "s/__PILLAR__LOCAL__DNS__/$localdns/g; s/__PILLAR__DNS__DOMAIN__/$domain/g; s/__PILLAR__DNS__SERVER__/$kubedns/g" nodelocaldns.yaml ``` - - `__PILLAR__CLUSTER__DNS__` and `__PILLAR__UPSTREAM__SERVERS__` will be populated by the node-local-dns pods. + + `__PILLAR__CLUSTER__DNS__` and `__PILLAR__UPSTREAM__SERVERS__` will be populated by the node-local-dns pods. In this mode, node-local-dns pods listen on both the kube-dns service IP as well as ``, so pods can lookup DNS records using either IP address. - * If kube-proxy is running in IPVS mode: - + * If kube-proxy is running in IPVS mode: + ``` bash sed -i "s/__PILLAR__LOCAL__DNS__/$localdns/g; s/__PILLAR__DNS__DOMAIN__/$domain/g; s/__PILLAR__DNS__SERVER__//g; s/__PILLAR__CLUSTER__DNS__/$kubedns/g" nodelocaldns.yaml ``` - In this mode, node-local-dns pods listen only on ``. The node-local-dns interface cannot bind the kube-dns cluster IP since the interface used for IPVS loadbalancing already uses this address. + In this mode, node-local-dns pods listen only on ``. The node-local-dns interface cannot bind the kube-dns cluster IP since the interface used for IPVS loadbalancing already uses this address. `__PILLAR__UPSTREAM__SERVERS__` will be populated by the node-local-dns pods. - + * Run `kubectl create -f nodelocaldns.yaml` * If using kube-proxy in IPVS mode, `--cluster-dns` flag to kubelet needs to be modified to use `` that NodeLocal DNSCache is listening on. Otherwise, there is no need to modify the value of the `--cluster-dns` flag, since NodeLocal DNSCache listens on both the kube-dns service IP as well as ``. diff --git a/content/zh/docs/tasks/administer-cluster/nodelocaldns.md b/content/zh/docs/tasks/administer-cluster/nodelocaldns.md index 2ae9d9d49b..8c50aa56ca 100644 --- a/content/zh/docs/tasks/administer-cluster/nodelocaldns.md +++ b/content/zh/docs/tasks/administer-cluster/nodelocaldns.md @@ -41,7 +41,7 @@ NodeLocal DNSCache improves Cluster DNS performance by running a dns caching age NodeLocal DNSCache 通过在集群节点上作为 DaemonSet 运行 dns 缓存代理来提高集群 DNS 性能。 在当今的体系结构中，处于 ClusterFirst DNS 模式的 Pod 可以连接到 kube-dns serviceIP 进行 DNS 查询。 通过 kube-proxy 添加的 iptables 规则将其转换为 kube-dns/CoreDNS 端点。 -借助这种新架构，Pods 将可以访问在同一节点上运行的 dns 缓存代理，从而避免了 iptables DNAT 规则和连接跟踪。 +借助这种新架构，Pods 将可以访问在同一节点上运行的 dns 缓存代理，从而避免了 iptables DNAT 规则和连接跟踪。 本地缓存代理将查询 kube-dns 服务以获取集群主机名的缓存缺失（默认为 cluster.local 后缀）。 * 使用当前的 DNS 体系结构，如果没有本地 kube-dns/CoreDNS 实例，则具有最高 DNS QPS 的 Pod 可能必须延伸到另一个节点。 @@ -94,9 +94,9 @@ This is the path followed by DNS Queries after NodeLocal DNSCache is enabled: -{{< figure src="/images/docs/nodelocaldns.jpg" alt="NodeLocal DNSCache 流" title="Nodelocal DNSCache 流" caption="此图显示了 NodeLocal DNSCache 如何处理 DNS 查询。" >}} +{{< figure src="/images/docs/nodelocaldns.svg" alt="NodeLocal DNSCache 流" title="Nodelocal DNSCache 流" caption="此图显示了 NodeLocal DNSCache 如何处理 DNS 查询。" >}}