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ArgoCD实践之基于配置清单创建Application

1. 什么是Application

后续内容会更新在个人站点: https.malusspectabilis.top

1.0 什么是基础不可变设施

GitOps当中是这样定义的。应用都需要运行在多台机器上，它们被组织成不同的环境，例如开发环境、测试环境和生产环境等等。需要将相同的应用部署到不同的机器上。通常需要系统管理员确保所有的机器都处于相同的状态。接着所有的修改、补丁、升级需要在所有的机器中进行。随着时间的推移，很难再确保所有的机器处于相同的状态，同时越来越容易出错。这就是传统的可变架构中经常出现的问题。这时我们有了不可变架构，它将整个机器环境打包成一个单一的不可变单元，而不是传统方式仅仅打包应用。这个单元包含了之前所说的整个环境栈和应用所有的修改、补丁和升级，这就解决了前面的问题。 —— 摘自 InfoQ 的《关于不可变架构以及为什么需要不可变架构》作者 百占辉

1.1 Application核心组件

Synced：一致
OutOfSync：不一致

Healthy：健康
Degraded：降级
Missing：缺失，即在GitRepo中存在资源定义，但并未完成部署
image

2. ArgoCD Application的创建

ArgoCD可以基于WEB-UI的方式来进行应用的发布，也可以基于Configuration List的方式去部署应用。

2.1 查看ArgoCD支持的API-Resources

kubectl api-resources --api-group=argoproj.io
NAME              SHORTNAMES         APIVERSION             NAMESPACED   KIND
applications      app,apps           argoproj.io/v1alpha1   true         Application
applicationsets   appset,appsets     argoproj.io/v1alpha1   true         ApplicationSet
appprojects       appproj,appprojs   argoproj.io/v1alpha1   true         AppProject

2.2 查看ArgoCD的字段属性

explain可以分级查看字段属性

[root@c-k-m1-10 argocd]# kubectl explain application
KIND:     Application
VERSION:  argoproj.io/v1alpha1

DESCRIPTION:
     Application is a definition of Application resource.

FIELDS:
   apiVersion	<string>
     APIVersion defines the versioned schema of this representation of an
     object. Servers should convert recognized schemas to the latest internal
     value, and may reject unrecognized values. More info:
     https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#resources

   kind	<string>
     Kind is a string value representing the REST resource this object
     represents. Servers may infer this from the endpoint the client submits
     requests to. Cannot be updated. In CamelCase. More info:
     https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#types-kinds

   metadata	<Object> -required-
     Standard object's metadata. More info:
     https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata

   operation	<Object>
     Operation contains information about a requested or running operation

   spec	<Object> -required-
     ApplicationSpec represents desired application state. Contains link to
     repository with application definition and additional parameters link
     definition revision.

   status	<Object>
     ApplicationStatus contains status information for the application

2.3 准备Git源

GitOps中定义以特定Repository(配置仓库)为应用程序部署和管理的唯一可信源，该Repository负责定义Application的期望状态。本次测试使用gitee作为唯一的可信源。支持更多的配置管理工具例如helm、kustomize、jsonnet等；本次使用kubernetes原生的配置清单包含如下一个namespace一个裸Pod以及一个Service。

kind: Namespace
apiVersion: v1
metadata:
  name: hello
  
apiVersion: v1
kind: Service
metadata:
  name: hello-svc
  namespace: hello
spec:
  type: NodePort
  selector:    
    app: hello
  ports:
  - name: http         # 端口名称
    protocol: TCP      # 协议类型，目前支持TCP、UDP、SCTP默认为TCP
    port: 80           # Service的端口号
    targetPort: 8080   # 后端目标进程的端口号
    nodePort:
	
apiVersion: v1
kind: Pod
metadata:
  name: hello
  namespace: hello
  labels:
     app: hello
spec:
  containers:
  - name: hello
    image: lihuahaitang/helloworld:v1
    imagePullPolicy: IfNotPresent

2.4 编辑资源配置清单；

[root@c-k-m1-10 argocd]# cat application-hello.yaml
apiVersion: argoproj.io/v1alpha1   # 定义的API版本，可通过API-Resources查看
kind: Application  # 定义的资源类型
metadata:
  name: hello  # 名称
  namespace: argocd   # argocd所在的名称空间
spec:
  project: default   # 指明所属的项目是default
  source:     # 配置仓库及相关的配置访问的方法
    repoURL: https://gitee.com/good-news/apps.git   # 资源配置清单的Git的仓库源地址
    targetRevision: HEAD                  # 期望基于哪个修订版本来部署 
    path: kubernetes    # Git仓库的子目录路径
  destination:       # 应用程序要部署到的目标位置
    server: https://kubernetes.default.svc     # 目标kubernetes集群的API-Server访问入口，这里为本地集群
    namespace: hello          # 目标应用要部署的名称空间
  syncPolicy:                 # 同步策略，如果不写默认就是Manual为手动同步
    automated: null                # 为自动同步策略

2.5 查看应用状态

这里的应用状态为未同步，因为我们未指定同步策略为自动。默认为手动同步；

[root@c-k-m1-10 argocd]# argocd app list
WARN[0000] Failed to invoke grpc call. Use flag --grpc-web in grpc calls. To avoid this warning message, use flag --grpc-web. 
NAME          CLUSTER                         NAMESPACE  PROJECT  STATUS  HEALTH  SYNCPOLICY  CONDITIONS  REPO                                  PATH        TARGET
argocd/hello  https://kubernetes.default.svc  hello      default                  <none>      <none>      https://gitee.com/good-news/apps.git  kubernetes  HEAD

2.6 手动执行同步策略

[root@c-k-m1-10 argocd]# argocd app sync hello
WARN[0000] Failed to invoke grpc call. Use flag --grpc-web in grpc calls. To avoid this warning message, use flag --grpc-web. 
TIMESTAMP                  GROUP        KIND   NAMESPACE                  NAME    STATUS   HEALTH        HOOK  MESSAGE
2023-03-25T22:00:35+08:00            Service     default                 hello   Unknown  Healthy              
2023-03-25T22:00:37+08:00            Service     default                 hello   Unknown  Healthy              ignored (requires pruning)
2023-03-25T22:00:37+08:00          Namespace       hello                 hello   Running   Synced              namespace/hello created
2023-03-25T22:00:37+08:00            Service       hello             hello-svc   Running   Synced              service/hello-svc created
2023-03-25T22:00:37+08:00                Pod       hello                 hello   Running   Synced              pod/hello created
2023-03-25T22:00:37+08:00            Service     default                 hello  OutOfSync  Healthy                  ignored (requires pruning)
2023-03-25T22:00:37+08:00            Service       hello             hello-svc  OutOfSync  Healthy                  service/hello-svc created
2023-03-25T22:00:37+08:00                Pod       hello                 hello    Synced   Progressing              pod/hello created
2023-03-25T22:00:37+08:00          Namespace                             hello    Synced                            

Name:               argocd/hello
Project:            default
Server:             https://kubernetes.default.svc
Namespace:          hello
URL:                https://argocd.k8s.local/applications/hello
Repo:               https://gitee.com/good-news/apps.git
Target:             HEAD
Path:               kubernetes
SyncWindow:         Sync Allowed
Sync Policy:        <none>
Sync Status:        OutOfSync from HEAD (c916463)
Health Status:      Healthy

Operation:          Sync
Sync Revision:      c916463463c2244ae78ba442a0de764b743a493b
Phase:              Succeeded
Start:              2023-03-25 22:00:34 +0800 CST
Finished:           2023-03-25 22:00:37 +0800 CST
Duration:           3s
Message:            successfully synced (all tasks run)

GROUP  KIND       NAMESPACE  NAME       STATUS     HEALTH   HOOK  MESSAGE
       Service    default    hello      OutOfSync  Healthy        ignored (requires pruning)
       Namespace  hello      hello      Running    Synced         namespace/hello created
       Service    hello      hello-svc  OutOfSync  Healthy        service/hello-svc created
       Pod        hello      hello      Synced     Healthy        pod/hello created

2.7 查看名称空间的Pod以及Service

[root@c-k-m1-10 argocd]# kubectl get po,svc -n hello 
NAME        READY   STATUS    RESTARTS   AGE
pod/hello   1/1     Running   0          5m22s

NAME                TYPE       CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE
service/hello-svc   NodePort   xx.xx.xx.xx   <none>        80:32618/TCP   5m22s

2.8 WEBUI查看应用状态

image

2.9 尝试访问应用

sh-3.2# curl -I http://xx.xx.xx.xx32618/
HTTP/1.1 200 OK
Date: Sat, 25 Mar 2023 14:07:57 GMT
Connection: keep-alive
posted @ 2023-03-26 12:59  梨花海棠  阅读(526)  评论(1)  编辑  收藏  举报