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作者:GreatSQL 社区
案例实践
2022-03-29

Chaos Mesh 最初作为开源分布式数据库 TiDB 的测试平台而创建,是一个多功能混沌工程平台,通过混沌测试验证分布式系统的稳定性。本文以万里安全数据库软件 GreatDB 分布式部署模式为例,介绍了通过 Chaos Mesh 进行混沌测试的全流程。

需求背景与 GreatDB 介绍

需求背景

混沌测试是检测分布式系统不确定性、建立系统弹性信心的一种非常好的方式,因此我们采用开源工具 Chaos Mesh 来做 GreatDB 分布式集群的混沌测试。

GreatDB 分布式部署模式介绍

万里安全数据库软件 GreatDB 是一款关系型数据库软件,同时支持集中式和分布式的部署方式,本文涉及的是分布式部署方式。

分布式部署模式采用 shared-nothing 架构;通过数据冗余与副本管理确保数据库无单点故障;数据 sharding 与分布式并行计算实现数据库系统高性能;可无限制动态扩展数据节点,满足业务需要。

整体架构如下图所示:

1.jpg

环境准备

Chaos Mesh 安装

在安装 Chaos Mesh 之前请确保已经预先安装了 helm,docker,并准备好了一个 kubernetes 环境。

  • 使用 Helm 安装

1)在 Helm 仓库中添加 Chaos Mesh 仓库:

helm repo add chaos-mesh https://charts.chaos-mesh.org

2)查看可以安装的 Chaos Mesh 版本:

helm search repo chaos-mesh

3)创建安装 Chaos Mesh 的命名空间:

kubectl create ns chaos-testing

4)在 docker 环境下安装 Chaos Mesh:

helm install chaos-mesh chaos-mesh/chaos-mesh -n=chaos-testing
  • 验证安装

执行以下命令查看 Chaos Mesh 的运行情况:

kubectl get pod -n chaos-testing

下面是预期输出:

NAME                                       READY   STATUS    RESTARTS   AGE
chaos-controller-manager-d7bc9ccb5-dbccq   1/1     Running   0          26d
chaos-daemon-pzxc7                         1/1     Running   0          26d
chaos-dashboard-5887f7559b-kgz46           1/1     Running   1          26d

如果 3 个 pod 的状态都是 Running,表示 Chaos Mesh 已经成功安装。

准备测试需要的镜像

准备 MySQL 镜像

一般情况下,MySQL 使用官方 5.7 版本的镜像,MySQL 监控采集器使用的是 mysqld-exporter,也可以直接从 docker hub 下载:

docker pull mysql:5.7
docker pull prom/mysqld-exporter

准备 ZooKeeper 镜像

ZooKeeper 使用的是官方 3.5.5 版本镜像,ZooKeeper 组件涉及的监控有 jmx-prometheus-exporter 和 zookeeper-exporter,均从 docker hub 下载:

docker pull zookeeper:3.5.5
docker pull sscaling/jmx-prometheus-exporter
docker pull josdotso/zookeeper-exporter

准备 GreatDB 镜像

选择一个 GreatDB 的 tar 包,将其解压得到一个 ./greatdb 目录,再将 greatdb-service-docker.sh 文件拷贝到这个解压出来的./greatdb 目录里:

cp greatdb-service-docker.sh ./greatdb/

将 greatdb Dockerfile 放到./greatdb 文件夹的同级目录下,然后执行以下命令构建 GreatDB 镜像:

docker build -t greatdb/greatdb:tag2021 .

准备 GreatDB 分布式集群部署/清理的镜像

下载集群部署脚本 cluster-setup,集群初始化脚本 init-zk 以及集群 helm charts 包(可咨询 4.0 开发/测试组获取)

将上述材料放在同一目录下,编写如下 Dockerfile:

FROM debian:buster-slim as init-zk
COPY ./init-zk /root/init-zk
RUN chmod +x /root/init-zk
FROM debian:buster-slim as cluster-setup
\*# Set aliyun repo for speed*
RUN sed -i 's/deb.debian.org/mirrors.aliyun.com/g' /etc/apt/sources.list && \
  sed -i 's/security.debian.org/mirrors.aliyun.com/g' /etc/apt/sources.list
RUN apt-get -y update && \
  apt-get -y install \
  curl \
  wget
RUN curl -L https://storage.googleapis.com/kubernetes-release/release/v1.20.1/bin/linux/amd64/kubectl -o /usr/local/bin/kubectl && \
  chmod +x /usr/local/bin/kubectl && \
  mkdir /root/.kube && \
  wget https://get.helm.sh/helm-v3.5.3-linux-amd64.tar.gz && \
  tar -zxvf helm-v3.5.3-linux-amd64.tar.gz && \
  mv linux-amd64/helm /usr/local/bin/helm
COPY ./config /root/.kube/
COPY ./helm /helm
COPY ./cluster-setup /

执行以下命令构建所需镜像:

docker build --target init-zk -t greatdb/initzk:latest .
docker build --target cluster-setup -t greatdb/cluster-setup:v1 .

准备测试用例的镜像

目前测试支持的用例有:bank、bank2、pbank、tpcc、flashback 等,每个用例都是一个可执行文件。

以 flashback 测例为例构建测试用例的镜像,先将用例下载到本地,在用例的同一目录下编写如下内容的 Dockerfile:

FROM debian:buster-slim
COPY ./flashback /
RUN cd / && chmod +x ./flashback

执行以下命令构建测试用例镜像:

docker build -t greatdb/testsuite-flashback:v1 .

将准备好的镜像上传到私有仓库中

创建私有仓库和上传镜像操作请参考:https://zhuanlan.zhihu.com/p/78543733

Chaos Mesh 的使用

搭建 GreatDB 分布式集群

在上一章中 cluster-setup 目录下执行以下命令块去搭建测试集群:

./cluster-setup  \
-clustername=c0 \
-namespace=test \
-enable-monitor=true \
-mysql-image=mysql:5.7 \
-mysql-replica=3 \
-mysql-auth=1 \
-mysql-normal=1 \
-mysql-global=1 \
-mysql-partition=1 \
-zookeeper-repository=zookeeper \
-zookeeper-tag=3.5.5 \
-zookeeper-replica=3 \
-greatdb-repository=greatdb/greatdb \
-greatdb-tag=tag202110 \
-greatdb-replica=3 \
-greatdb-serviceHost=172.16.70.249

输出信息:

liuxinle@liuxinle-OptiPlex-5060:~/k8s/cluster-setup$ ./cluster-setup \
\> -clustername=c0 \
\> -namespace=test \
\> -enable-monitor=true \
\> -mysql-image=mysql:5.7 \
\> -mysql-replica=3 \
\> -mysql-auth=1 \
\> -mysql-normal=1 \
\> -mysql-global=1 \
\> -mysql-partition=1 \
\> -zookeeper-repository=zookeeper \
\> -zookeeper-tag=3.5.5 \
\> -zookeeper-replica=3 \
\> -greatdb-repository=greatdb/greatdb \
\> -greatdb-tag=tag202110 \
\> -greatdb-replica=3 \
\> -greatdb-serviceHost=172.16.70.249
INFO[2021-10-14T10:41:52+08:00] SetUp the cluster ...                         NameSpace=test
INFO[2021-10-14T10:41:52+08:00] create namespace ...                         
INFO[2021-10-14T10:41:57+08:00] copy helm chart templates ...                
INFO[2021-10-14T10:41:57+08:00] setup ...                                     Component=MySQL
INFO[2021-10-14T10:41:57+08:00] exec helm install and update greatdb-cfg.yaml ... 
INFO[2021-10-14T10:42:00+08:00] waiting mysql pods running ...               
INFO[2021-10-14T10:44:27+08:00] setup ...                                     Component=Zookeeper
INFO[2021-10-14T10:44:28+08:00] waiting zookeeper pods running ...           
INFO[2021-10-14T10:46:59+08:00] update greatdb-cfg.yaml                      
INFO[2021-10-14T10:46:59+08:00] setup ...                                     Component=greatdb
INFO[2021-10-14T10:47:00+08:00] waiting greatdb pods running ...             
INFO[2021-10-14T10:47:21+08:00] waiting cluster running ...                  
INFO[2021-10-14T10:47:27+08:00] waiting prometheus server running...         
INFO[2021-10-14T10:47:27+08:00] Dump Cluster Info                            
INFO[2021-10-14T10:47:27+08:00] SetUp success.                                ClusterName=c0 NameSpace=test

执行如下命令,查看集群 pod 状态:

kubectl get pod -n test -o wide

输出信息:

NAME                                    READY   STATUS      RESTARTS   AGE     IP             NODE                     NOMINATED NODE   READINESS GATES
c0-auth0-mysql-0                        2/2     Running     0          10m     10.244.87.18   liuxinle-optiplex-5060   <none>           <none>
c0-auth0-mysql-1                        2/2     Running     0          9m23s   10.244.87.54   liuxinle-optiplex-5060   <none>           <none>
c0-auth0-mysql-2                        2/2     Running     0          8m39s   10.244.87.57   liuxinle-optiplex-5060   <none>           <none>
c0-greatdb-0                            2/2     Running     1          5m3s    10.244.87.58   liuxinle-optiplex-5060   <none>           <none>
c0-greatdb-1                            2/2     Running     0          4m57s   10.244.87.20   liuxinle-optiplex-5060   <none>           <none>
c0-greatdb-2                            2/2     Running     0          4m50s   10.244.87.47   liuxinle-optiplex-5060   <none>           <none>
c0-glob0-mysql-0                        2/2     Running     0          10m     10.244.87.51   liuxinle-optiplex-5060   <none>           <none>
c0-glob0-mysql-1                        2/2     Running     0          9m23s   10.244.87.41   liuxinle-optiplex-5060   <none>           <none>
c0-glob0-mysql-2                        2/2     Running     0          8m38s   10.244.87.60   liuxinle-optiplex-5060   <none>           <none>
c0-nor0-mysql-0                         2/2     Running     0          10m     10.244.87.29   liuxinle-optiplex-5060   <none>           <none>
c0-nor0-mysql-1                         2/2     Running     0          9m29s   10.244.87.4    liuxinle-optiplex-5060   <none>           <none>
c0-nor0-mysql-2                         2/2     Running     0          8m45s   10.244.87.25   liuxinle-optiplex-5060   <none>           <none>
c0-par0-mysql-0                         2/2     Running     0          10m     10.244.87.55   liuxinle-optiplex-5060   <none>           <none>
c0-par0-mysql-1                         2/2     Running     0          9m26s   10.244.87.13   liuxinle-optiplex-5060   <none>           <none>
c0-par0-mysql-2                         2/2     Running     0          8m42s   10.244.87.21   liuxinle-optiplex-5060   <none>           <none>
c0-prometheus-server-6697649b76-fkvh9   2/2     Running     0          4m36s   10.244.87.37   liuxinle-optiplex-5060   <none>           <none>
c0-zookeeper-0                          1/1     Running     1          7m35s   10.244.87.44   liuxinle-optiplex-5060   <none>           <none>
c0-zookeeper-1                          1/1     Running     0          6m41s   10.244.87.30   liuxinle-optiplex-5060   <none>           <none>
c0-zookeeper-2                          1/1     Running     0          6m10s   10.244.87.49   liuxinle-optiplex-5060   <none>           <none>
c0-zookeeper-initzk-7hbfs               0/1     Completed   0          7m35s   10.244.87.17   liuxinle-optiplex-5060   <none>           <none>

看到 c0-zookeeper-initzk-7hbfs 的状态是 Completed,其他 pod 的状态为 Running,表示集群搭建成功。

在 GreatDB 分布式集群中使用 Chaos Mesh 做混沌测试

Chaos Mesh 在 kubernetes 环境支持注入的故障类型包括:模拟 Pod 故障、模拟网络故障、模拟压力场景等,这里我们以模拟 Pod 故障中的 pod-kill 为例。

将实验配置写入到文件中 pod-kill.yaml,内容示例如下:

apiVersion: chaos-mesh.org/v1alpha1
kind: PodChaos   *# 要注入的故障类型*
metadata:
  name: pod-failure-example
  namespace: test   *# 测试集群pod所在的namespace*
spec:
  action: pod-kill   *# 要注入的具体故障类型*
  mode: all    *# 指定实验的运行方式,all(表示选出所有符合条件的 Pod)*
  duration: '30s'    *# 指定实验的持续时间* 
  selector: 
    labelSelectors:
      "app.kubernetes.io/component": "greatdb"    *# 指定注入故障目标pod的标签,通过kubectl describe pod c0-greatdb-1 -n test 命令返回结果中Labels后的内容得到*

创建故障实验,命令如下:

kubectl create -n test -f pod-kill.yaml

创建完故障实验之后,执行命令 kubectl get pod -n test -o wide 结果如下:

NAME                                    READY   STATUS              RESTARTS   AGE     IP             NODE                     NOMINATED NODE   READINESS GATES
c0-auth0-mysql-0                        2/2     Running             0          14m     10.244.87.18   liuxinle-optiplex-5060   <none>           <none>
c0-auth0-mysql-1                        2/2     Running             0          14m     10.244.87.54   liuxinle-optiplex-5060   <none>           <none>
c0-auth0-mysql-2                        2/2     Running             0          13m     10.244.87.57   liuxinle-optiplex-5060   <none>           <none>
c0-greatdb-0                            0/2     ContainerCreating   0          2s      <none>         liuxinle-optiplex-5060   <none>           <none>
c0-greatdb-1                            0/2     ContainerCreating   0          2s      <none>         liuxinle-optiplex-5060   <none>           <none>
c0-glob0-mysql-0                        2/2     Running             0          14m     10.244.87.51   liuxinle-optiplex-5060   <none>           <none>
c0-glob0-mysql-1                        2/2     Running             0          14m     10.244.87.41   liuxinle-optiplex-5060   <none>           <none>
c0-glob0-mysql-2                        2/2     Running             0          13m     10.244.87.60   liuxinle-optiplex-5060   <none>           <none>
c0-nor0-mysql-0                         2/2     Running             0          14m     10.244.87.29   liuxinle-optiplex-5060   <none>           <none>
c0-nor0-mysql-1                         2/2     Running             0          14m     10.244.87.4    liuxinle-optiplex-5060   <none>           <none>
c0-nor0-mysql-2                         2/2     Running             0          13m     10.244.87.25   liuxinle-optiplex-5060   <none>           <none>
c0-par0-mysql-0                         2/2     Running             0          14m     10.244.87.55   liuxinle-optiplex-5060   <none>           <none>
c0-par0-mysql-1                         2/2     Running             0          14m     10.244.87.13   liuxinle-optiplex-5060   <none>           <none>
c0-par0-mysql-2                         2/2     Running             0          13m     10.244.87.21   liuxinle-optiplex-5060   <none>           <none>
c0-prometheus-server-6697649b76-fkvh9   2/2     Running             0          9m24s   10.244.87.37   liuxinle-optiplex-5060   <none>           <none>
c0-zookeeper-0                          1/1     Running             1          12m     10.244.87.44   liuxinle-optiplex-5060   <none>           <none>
c0-zookeeper-1                          1/1     Running             0          11m     10.244.87.30   liuxinle-optiplex-5060   <none>           <none>
c0-zookeeper-2                          1/1     Running             0          10m     10.244.87.49   liuxinle-optiplex-5060   <none>           <none>
c0-zookeeper-initzk-7hbfs               0/1     Completed           0          12m     10.244.87.17   liuxinle-optiplex-5060   <none>           <none>

可以看到有带 greatdb 名字的 pod 正在被重启,说明注入故障成功。

在 Argo 中编排测试流程

Argo 是一个开源的容器本地工作流引擎,用于在 Kubernetes 上完成工作,可以将多步骤工作流建模为一系列任务,完成测试流程编排。

我们使用 argo 定义一个测试任务,基本的测试流程是固定的,如下所示:

2.jpg

测试流程的 step1 是部署测试集群,接着开启两个并行任务,step2 跑测试用例,模拟业务场景,step3 同时使用 Chaos Mesh 注入故障,step2 的测试用例执行结束之后,step4 终止故障注入,最后 step5 清理集群环境。

用 Argo 编排一个混沌测试工作流(以 flashback 测试用例为例)

1)修改 cluster-setup.yaml 中的 image 信息,改成步骤“准备测试需要的镜像”中自己传上去的集群部署/清理镜像名和 tag

2)修改 testsuite-flashback.yaml 中的 image 信息,改成步骤“准备测试需要的镜像”中自己传上去的测试用例镜像名和 tag

3)将集群部署、测试用例和工具模板的 yaml 文件全部使用 kubectl apply -n argo -f xxx.yaml 命令创建资源 (这些文件定义了一些 argo template,方便用户写 workflow 时候使用)

kubectl apply -n argo -f cluster-setup.yaml
kubectl apply -n argo -f testsuite-flashback.yaml
kubectl apply -n argo -f tools-template.yaml

4)复制一份 workflow 模板文件 workflow-template.yaml,将模板文件中注释提示的部分修改为自己的设置即可,然后执行以下命令创建混沌测试工作流:

kubectl apply -n argo -f workflow-template.yaml

以下是一份 workflow 模板文件:

apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: chaostest-c0-0-
  name: chaostest-c0-0
  namespace: argo
spec:
  entrypoint: test-entry #测试入口,在这里传入测试参数,填写clustername、namespace、host、greatdb镜像名和tag名等基本信息
  serviceAccountName: argo
  arguments:
    parameters:
      - name: clustername
        value: c0
      - name: namespace
        value: test
      - name: host
        value: 172.16.70.249
      - name: port
        value: 30901
      - name: password
        value: Bgview@2020
      - name: user
        value: root
      - name: run-time
        value: 10m
      - name: greatdb-repository
        value: greatdb/greatdb
      - name: greatdb-tag
        value: tag202110
      - name: nemesis
        value: kill_mysql_normal_master,kill_mysql_normal_slave,kill_mysql_partition_master,kill_mysql_partition_slave,kill_mysql_auth_master,kill_mysql_auth_slave,kill_mysql_global_master,kill_mysql_global_slave,kill_mysql_master,kill_mysql_slave,net_partition_mysql_normal,net_partition_mysql_partition,net_partition_mysql_auth,net_partition_mysql_global
      - name: mysql-partition
        value: 1
      - name: mysql-global
        value: 1
      - name: mysql-auth
        value: 1
      - name: mysql-normal
        value: 2
  templates:
    - name: test-entry
      steps:
        - - name: setup-greatdb-cluster  # step.1 集群部署. 请指定正确的参数,主要是mysql和zookeeper的镜像名、tag名
            templateRef:
              name: cluster-setup-template
              template: cluster-setup
            arguments:
              parameters:
                - name: namespace
                  value: "{{workflow.parameters.namespace}}"
                - name: clustername
                  value: "{{workflow.parameters.clustername}}"
                - name: mysql-image
                  value: mysql:5.7.34
                - name: mysql-replica
                  value: 3
                - name: mysql-auth
                  value: "{{workflow.parameters.mysql-auth}}"
                - name: mysql-normal
                  value: "{{workflow.parameters.mysql-normal}}"
                - name: mysql-partition
                  value: "{{workflow.parameters.mysql-partition}}"
                - name: mysql-global
                  value: "{{workflow.parameters.mysql-global}}"
                - name: enable-monitor
                  value: false
                - name: zookeeper-repository
                  value: zookeeper
                - name: zookeeper-tag
                  value: 3.5.5
                - name: zookeeper-replica
                  value: 3
                - name: greatdb-repository
                  value: "{{workflow.parameters.greatdb-repository}}"
                - name: greatdb-tag
                  value: "{{workflow.parameters.greatdb-tag}}"
                - name: greatdb-replica
                  value: 3
                - name: greatdb-serviceHost
                  value: "{{workflow.parameters.host}}"
                - name: greatdb-servicePort
                  value: "{{workflow.parameters.port}}"
        - - name: run-flashbacktest    # step.2 运行测试用例,请替换为你要运行的测试用例template并指定正确的参数,主要是测试使用的表个数和大小
            templateRef:
              name: flashback-test-template
              template: flashback
            arguments:
              parameters:
                - name: user
                  value: "{{workflow.parameters.user}}"
                - name: password
                  value: "{{workflow.parameters.password}}"
                - name: host
                  value: "{{workflow.parameters.host}}"
                - name: port
                  value: "{{workflow.parameters.port}}"
                - name: concurrency
                  value: 16
                - name: size
                  value: 10000
                - name: tables
                  value: 10
                - name: run-time
                  value: "{{workflow.parameters.run-time}}"
                - name: single-statement
                  value: true
                - name: manage-statement
                  value: true
          - name: invoke-chaos-for-flashabck-test    # step.3 注入故障,请指定正确的参数,这里run-time和interval分别定义了故障注入的时间和频次,因此省略掉了终止故障注入步骤
            templateRef:
              name: chaos-rto-template
              template: chaos-rto
            arguments:
              parameters:
                - name: user
                  value: "{{workflow.parameters.user}}"
                - name: host
                  value: "{{workflow.parameters.host}}"
                - name: password
                  value: "{{workflow.parameters.password}}"
                - name: port
                  value: "{{workflow.parameters.port}}"
                - name: k8s-config
                  value: /root/.kube/config
                - name: namespace
                  value: "{{workflow.parameters.namespace}}"
                - name: clustername
                  value: "{{workflow.parameters.clustername}}"
                - name: prometheus
                  value: ''
                - name: greatdb-job
                  value: greatdb-monitor-greatdb
                - name: nemesis
                  value: "{{workflow.parameters.nemesis}}"
                - name: nemesis-duration
                  value: 1m
                - name: nemesis-mode
                  value: default
                - name: wait-time
                  value: 5m
                - name: check-time
                  value: 5m
                - name: nemesis-scope
                  value: 1
                - name: nemesis-log
                  value: true
                - name: enable-monitor
                  value: false
                - name: run-time
                  value: "{{workflow.parameters.run-time}}"
                - name: interval
                  value: 1m
                - name: monitor-log
                  value: false
                - name: enable-rto
                  value: false
                - name: rto-qps
                  value: 0.1
                - name: rto-warm
                  value: 5m
                - name: rto-time
                  value: 1m
                - name: log-level
                  value: debug
        - - name: flashbacktest-output         # 输出测试用例是否通过的结果
            templateRef:
              name: tools-template
              template: output-result
            arguments:
              parameters:
                - name: info
                  value: "flashback test pass, with nemesis: {{workflow.parameters.nemesis}}"
        - - name: clean-greatdb-cluster           # step.4 清理测试集群,这里的参数和step.1的参数一致
            templateRef:
              name: cluster-setup-template
              template: cluster-setup
            arguments:
              parameters:
                - name: namespace
                  value: "{{workflow.parameters.namespace}}"
                - name: clustername
                  value: "{{workflow.parameters.clustername}}"
                - name: mysql-image
                  value: mysql:5.7
                - name: mysql-replica
                  value: 3
                - name: mysql-auth
                  value: "{{workflow.parameters.mysql-auth}}"
                - name: mysql-normal
                  value: "{{workflow.parameters.mysql-normal}}"
                - name: mysql-partition
                  value: "{{workflow.parameters.mysql-partition}}"
                - name: mysql-global
                  value: "{{workflow.parameters.mysql-global}}"
                - name: enable-monitor
                  value: false
                - name: zookeeper-repository
                  value: zookeeper
                - name: zookeeper-tag
                  value: 3.5.5
                - name: zookeeper-replica
                  value: 3
                - name: greatdb-repository
                  value: "{{workflow.parameters.greatdb-repository}}"
                - name: greatdb-tag
                  value: "{{workflow.parameters.greatdb-tag}}"
                - name: greatdb-replica
                  value: 3
                - name: greatdb-serviceHost
                  value: "{{workflow.parameters.host}}"
                - name: greatdb-servicePort
                  value: "{{workflow.parameters.port}}"
                - name: clean
                  value: true
        - - name: echo-result
            templateRef:
              name: tools-template
              template: echo
            arguments:
              parameters:
                - name: info
                  value: "{{item}}"
            withItems:
              - "{{steps.flashbacktest-output.outputs.parameters.result}}"

至此,你已经成功使用 Chaos Mesh 进行了一次混沌测试,并成功验证了分布式系统的稳定性。

Now enjoy GreatSQL, and enjoy Chaos Mesh 🙂

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