348 lines
11 KiB
Markdown
348 lines
11 KiB
Markdown
# 安装并试用Istio service mesh
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本文根据官网的文档整理而成，步骤包括安装`istio 0.1.5`并创建一个bookinfo的微服务来测试istio的功能。
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文中使用的yaml文件可以在[kubernetes-handbook](https://github.com/rootsongjc/kubernetes-handbook)的`manifests/istio`目录中找到，所有的镜像都换成了我的私有镜像仓库地址，请根据官网的镜像自行修改。
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## 安装环境
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- CentOS 7.3.1611
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- Docker 1.12.6
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- Kubernetes 1.6.0
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## 安装
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**1.下载安装包**
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下载地址：https://github.com/istio/istio/releases
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下载Linux版本的当前最新版安装包
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```Shell
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wget https://github.com/istio/istio/releases/download/0.1.5/istio-0.1.5-linux.tar.gz
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```
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**2.解压**
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解压后，得到的目录结构如下：
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```
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.
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├── bin
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│ └── istioctl
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├── install
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│ └── kubernetes
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│ ├── addons
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│ │ ├── grafana.yaml
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│ │ ├── prometheus.yaml
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│ │ ├── servicegraph.yaml
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│ │ └── zipkin.yaml
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│ ├── istio-auth.yaml
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│ ├── istio-rbac-alpha.yaml
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│ ├── istio-rbac-beta.yaml
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│ ├── istio.yaml
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│ ├── README.md
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│ └── templates
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│ ├── istio-auth
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│ │ ├── istio-auth-with-cluster-ca.yaml
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│ │ ├── istio-cluster-ca.yaml
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│ │ ├── istio-egress-auth.yaml
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│ │ ├── istio-ingress-auth.yaml
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│ │ └── istio-namespace-ca.yaml
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│ ├── istio-egress.yaml
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│ ├── istio-ingress.yaml
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│ ├── istio-manager.yaml
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│ └── istio-mixer.yaml
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├── istio.VERSION
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├── LICENSE
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└── samples
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├── apps
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│ ├── bookinfo
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│ │ ├── bookinfo.yaml
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│ │ ├── cleanup.sh
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│ │ ├── destination-ratings-test-delay.yaml
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│ │ ├── loadbalancing-policy-reviews.yaml
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│ │ ├── mixer-rule-additional-telemetry.yaml
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│ │ ├── mixer-rule-empty-rule.yaml
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│ │ ├── mixer-rule-ratings-denial.yaml
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│ │ ├── mixer-rule-ratings-ratelimit.yaml
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│ │ ├── README.md
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│ │ ├── route-rule-all-v1.yaml
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│ │ ├── route-rule-delay.yaml
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│ │ ├── route-rule-reviews-50-v3.yaml
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│ │ ├── route-rule-reviews-test-v2.yaml
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│ │ ├── route-rule-reviews-v2-v3.yaml
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│ │ └── route-rule-reviews-v3.yaml
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│ ├── httpbin
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│ │ ├── httpbin.yaml
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│ │ └── README.md
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│ └── sleep
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│ ├── README.md
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│ └── sleep.yaml
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└── README.md
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11 directories, 41 files
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```
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从文件里表中可以看到，安装包中包括了kubernetes的yaml文件，示例应用和安装模板。
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**3.安装istioctl**
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将`./bin/istioctl`拷贝到你的`$PATH`目录下。
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**4.检查RBAC**
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因为我们安装的kuberentes版本是1.6.0默认支持RBAC，这一步可以跳过。如果你使用的其他版本的kubernetes，请参考[官方文档](https://istio.io/docs/tasks/installing-istio.html)操作。
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执行以下命令，正确的输出是这样的：
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```bash
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$ kubectl api-versions | grep rbac
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rbac.authorization.k8s.io/v1alpha1
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rbac.authorization.k8s.io/v1beta1
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```
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**5.创建角色绑定**
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```bash
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$ kubectl create -f install/kubernetes/istio-rbac-beta.yaml
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clusterrole "istio-manager" created
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clusterrole "istio-ca" created
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clusterrole "istio-sidecar" created
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clusterrolebinding "istio-manager-admin-role-binding" created
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clusterrolebinding "istio-ca-role-binding" created
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clusterrolebinding "istio-ingress-admin-role-binding" created
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clusterrolebinding "istio-sidecar-role-binding" created
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```
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注意：官网的安装包中的该文件中存在RoleBinding错误，应该是集群级别的`clusterrolebinding`，而release里的代码只是普通的`rolebinding`，查看该Issue [Istio manager cannot list of create k8s TPR when RBAC enabled #327](https://github.com/istio/istio/issues/327)。
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**6.安装istio核心组件**
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用到的镜像有：
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```
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docker.io/istio/mixer:0.1.5
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docker.io/istio/manager:0.1.5
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docker.io/istio/proxy_debug:0.1.5
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```
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我们暂时不开启[Istio Auth](https://istio.io/docs/concepts/network-and-auth/auth.html)。
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> 本文中用到的所有yaml文件中的`type: LoadBalancer`去掉，使用默认的ClusterIP，然后配置Traefik ingress，就可以在集群外部访问。请参考[安装Traefik ingress](../practice/traefik-ingress-installation.md)。
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```bash
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kubectl apply -f install/kubernetes/istio.yaml
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```
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**7.安装监控插件**
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用到的镜像有：
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```
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docker.io/istio/grafana:0.1.5
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quay.io/coreos/prometheus:v1.1.1
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gcr.io/istio-testing/servicegraph:latest
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docker.io/openzipkin/zipkin:latest
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```
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为了方便下载，其中两个镜像我备份到了时速云：
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```
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index.tenxcloud.com/jimmy/prometheus:v1.1.1
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index.tenxcloud.com/jimmy/servicegraph:latest
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```
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安装插件
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```bash
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kubectl apply -f install/kubernetes/addons/prometheus.yaml
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kubectl apply -f install/kubernetes/addons/grafana.yaml
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kubectl apply -f install/kubernetes/addons/servicegraph.yaml
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kubectl apply -f install/kubernetes/addons/zipkin.yaml
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```
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在traefik ingress中增加增加以上几个服务的配置，同时增加istio-ingress配置。
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```Yaml
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- host: grafana.istio.io
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http:
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paths:
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- path: /
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backend:
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serviceName: grafana
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servicePort: 3000
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- host: servicegraph.istio.io
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http:
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paths:
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- path: /
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backend:
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serviceName: servicegraph
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servicePort: 8088
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- host: prometheus.istio.io
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http:
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paths:
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- path: /
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backend:
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serviceName: prometheus
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servicePort: 9090
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- host: zipkin.istio.io
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http:
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paths:
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- path: /
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backend:
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serviceName: zipkin
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servicePort: 9411
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- host: ingress.istio.io
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http:
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paths:
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- path: /
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backend:
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serviceName: istio-ingress
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servicePort: 80
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```
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## 测试
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我们使用Istio提供的测试应用[bookinfo](https://istio.io/docs/samples/bookinfo.html)微服务来进行测试。
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该微服务用到的镜像有：
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```
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istio/examples-bookinfo-details-v1
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istio/examples-bookinfo-ratings-v1
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istio/examples-bookinfo-reviews-v1
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istio/examples-bookinfo-reviews-v2
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istio/examples-bookinfo-reviews-v3
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istio/examples-bookinfo-productpage-v1
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```
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该应用架构图如下：
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**部署应用**
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```
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kubectl create -f <(istioctl kube-inject -f samples/apps/bookinfo/bookinfo.yaml)
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```
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`Istio kube-inject`命令会在`bookinfo.yaml`文件中增加Envoy sidecar信息。参考：https://istio.io/docs/reference/commands/istioctl.html#istioctl-kube-inject
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在本机的`/etc/hosts`下增加VIP节点和`ingress.istio.io`的对应信息。具体步骤参考：[边缘节点配置](../practice/edge-node-configuration.md)
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在浏览器中访问http://ingress.istio.io/productpage
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多次刷新页面，你会发现有的页面上的评论里有星级打分，有的页面就没有，这是因为我们部署了三个版本的应用，有的应用里包含了评分，有的没有。Istio根据默认策略随机将流量分配到三个版本的应用上。
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查看部署的bookinfo应用中的`productpage-v1` service和deployment，查看`productpage-v1`的pod的详细json信息可以看到这样的结构：
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```bash
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$ kubectl get productpage-v1-944450470-bd530 -o json
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```
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见[productpage-v1-istio.json](../manifests/istio/productpage-v1-istio.json)文件。从详细输出中可以看到这个Pod中实际有两个容器，这里面包括了`initContainer`，作为istio植入到kubernetes deployment中的sidecar。
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```json
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"initContainers": [
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{
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"args": [
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"-p",
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"15001",
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"-u",
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"1337"
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],
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"image": "docker.io/istio/init:0.1",
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"imagePullPolicy": "Always",
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"name": "init",
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"resources": {},
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"securityContext": {
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"capabilities": {
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"add": [
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"NET_ADMIN"
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]
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}
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},
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"terminationMessagePath": "/dev/termination-log",
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"terminationMessagePolicy": "File",
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"volumeMounts": [
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{
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"mountPath": "/var/run/secrets/kubernetes.io/serviceaccount",
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"name": "default-token-3l9f0",
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"readOnly": true
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}
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]
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},
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{
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"args": [
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"-c",
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"sysctl -w kernel.core_pattern=/tmp/core.%e.%p.%t \u0026\u0026 ulimit -c unlimited"
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],
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"command": [
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"/bin/sh"
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],
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"image": "alpine",
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"imagePullPolicy": "Always",
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"name": "enable-core-dump",
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"resources": {},
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"securityContext": {
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"privileged": true
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},
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"terminationMessagePath": "/dev/termination-log",
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"terminationMessagePolicy": "File",
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"volumeMounts": [
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{
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"mountPath": "/var/run/secrets/kubernetes.io/serviceaccount",
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"name": "default-token-3l9f0",
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"readOnly": true
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}
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]
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}
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],
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```
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## 监控
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不断刷新productpage页面，将可以在以下几个监控中看到如下界面。
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**Grafana页面**
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http://grafana.istio.io
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**Prometheus页面**
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http://prometheus.istio.io
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**Zipkin页面**
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http://zipkin.istio.io
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**ServiceGraph页面**
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http://servicegraph.istio.io/dotviz
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可以用来查看服务间的依赖关系。
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访问http://servicegraph.istio.io/graph可以获得json格式的返回结果。
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## 更进一步
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BookInfo示例中有三个版本的`reviews`，可以使用istio来配置路由请求，将流量分摊到不同版本的应用上。参考[Configuring Request Routing](https://istio.io/docs/tasks/request-routing.html)。
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还有一些更高级的功能，我们后续将进一步探索。
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## 参考
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[Installing Istio](https://istio.io/docs/tasks/installing-istio.html)
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[BookInfo sample](https://istio.io/docs/samples/bookinfo.html) |