Version: v1.0

检索 Applications

本章节我们将介绍如何检索 application 相关的资源。

获取 Application 列表

  1. $ kubectl get application
  2. NAME        COMPONENT   TYPE         PHASE     HEALTHY   STATUS   AGE
  3. app-basic   app-basic   webservice   running   true               12d
  4. website     frontend    webservice   running   true               4m54s

我们可以使用 application 缩写 kubectl get app 。

查看 Application 详情

  1. $ kubectl get app website -o yaml
  2. apiVersion: core.oam.dev/v1beta1
  3. kind: Application
  4. metadata:
  5.   generation: 1
  6.   name: website
  7.   namespace: default
  8. spec:
  9.   components:
  10.   - name: frontend
  11.     properties:
  12.       image: nginx
  13.     traits:
  14.     - properties:
  15.         cpuPercent: 60
  16.         max: 10
  17.         min: 1
  18.       type: cpuscaler
  19.     - properties:
  20.         image: fluentd
  21.         name: sidecar-test
  22.       type: sidecar
  23.     type: webservice
  24.   - name: backend
  25.     properties:
  26.       cmd:
  27.       - sleep
  28.       - "1000"
  29.       image: busybox
  30.     type: worker
  31. status:
  32.   ...
  33.   latestRevision:
  34.     name: website-v1
  35.     revision: 1
  36.     revisionHash: e9e062e2cddfe5fb
  37.   services:
  38.   - healthy: true
  39.     name: frontend
  40.     traits:
  41.     - healthy: true
  42.       type: cpuscaler
  43.     - healthy: true
  44.       type: sidecar
  45.   - healthy: true
  46.     name: backend
  47.   status: running

以下是需要我们了解的一些重要信息：

  1. status.latestRevision 用于显示 application 当前运行的版本。
  2. status.services 用于显示 application 中 component 的健康状态。
  3. status.status 用于显示 application 的全局状态。

获取 Application 版本

KubeVela 会对 application 对每次 spec 变更生成新版本。

  1. $ kubectl get apprev -l app.oam.dev/name=website
  2. NAME           AGE
  3. website-v1     35m

检索 Components

我们可以检索出当前 KubeVela 中支持的 ComponentDefinition 列表。

  1. kubectl get comp -n vela-system
  2. NAME              WORKLOAD-KIND   DESCRIPTION                        
  3. task              Job             Describes jobs that run code or a script to completion.                                                                                          
  4. webservice        Deployment      Describes long-running, scalable, containerized services that have a stable network endpoint to receive external network traffic from customers. 
  5. worker            Deployment      Describes long-running, scalable, containerized services that running at backend. They do NOT have network endpoint to receive external network traffic.

正常情况下 ComponentDefinition 只能被同 namespace 下 application 引用，但是 vela-system namespace 下可以被所有 application 引用。

  1. $ kubectl vela show webservice
  2. # Properties
  3. +------------------+----------------------------------------------------------------------------------+-----------------------+----------+---------+
  4. |       NAME       |                                   DESCRIPTION                                    |         TYPE          | REQUIRED | DEFAULT |
  5. +------------------+----------------------------------------------------------------------------------+-----------------------+----------+---------+
  6. | cmd              | Commands to run in the container                                                 | []string              | false    |         |
  7. | env              | Define arguments by using environment variables                                  | [[]env](#env)         | false    |         |
  8. | addRevisionLabel |                                                                                  | bool                  | true     | false   |
  9. | image            | Which image would you like to use for your service                               | string                | true     |         |
  10. | port             | Which port do you want customer traffic sent to                                  | int                   | true     |      80 |
  11. | cpu              | Number of CPU units for the service, like `0.5` (0.5 CPU core), `1` (1 CPU core) | string                | false    |         |
  12. | volumes          | Declare volumes and volumeMounts                                                 | [[]volumes](#volumes) | false    |         |
  13. +------------------+----------------------------------------------------------------------------------+-----------------------+----------+---------+
  18. ##### volumes
  19. +-----------+---------------------------------------------------------------------+--------+----------+---------+
  20. |   NAME    |                             DESCRIPTION                             |  TYPE  | REQUIRED | DEFAULT |
  21. +-----------+---------------------------------------------------------------------+--------+----------+---------+
  22. | name      |                                                                     | string | true     |         |
  23. | mountPath |                                                                     | string | true     |         |
  24. | type      | Specify volume type, options: "pvc","configMap","secret","emptyDir" | string | true     |         |
  25. +-----------+---------------------------------------------------------------------+--------+----------+---------+
  30. ## env
  31. +-----------+-----------------------------------------------------------+-------------------------+----------+---------+
  32. |   NAME    |                        DESCRIPTION                        |          TYPE           | REQUIRED | DEFAULT |
  33. +-----------+-----------------------------------------------------------+-------------------------+----------+---------+
  34. | name      | Environment variable name                                 | string                  | true     |         |
  35. | value     | The value of the environment variable                     | string                  | false    |         |
  36. | valueFrom | Specifies a source the value of this var should come from | [valueFrom](#valueFrom) | false    |         |
  37. +-----------+-----------------------------------------------------------+-------------------------+----------+---------+
  42. ### valueFrom
  43. +--------------+--------------------------------------------------+-------------------------------+----------+---------+
  44. |     NAME     |                   DESCRIPTION                    |             TYPE              | REQUIRED | DEFAULT |
  45. +--------------+--------------------------------------------------+-------------------------------+----------+---------+
  46. | secretKeyRef | Selects a key of a secret in the pod's namespace | [secretKeyRef](#secretKeyRef) | true     |         |
  47. +--------------+--------------------------------------------------+-------------------------------+----------+---------+
  52. #### secretKeyRef
  53. +------+------------------------------------------------------------------+--------+----------+---------+
  54. | NAME |                           DESCRIPTION                            |  TYPE  | REQUIRED | DEFAULT |
  55. +------+------------------------------------------------------------------+--------+----------+---------+
  56. | name | The name of the secret in the pod's namespace to select from     | string | true     |         |
  57. | key  | The key of the secret to select from. Must be a valid secret key | string | true     |         |
  58. +------+------------------------------------------------------------------+--------+----------+---------+

检索 Traits

我们可以检索出当前 KubeVela 中支持对 TraitDefinitions 。

  1. $ kubectl get trait -n vela-system
  2. NAME                                       APPLIES-TO            DESCRIPTION                                     
  3. cpuscaler                                  [webservice worker]   configure k8s HPA with CPU metrics for Deployment
  4. ingress                                    [webservice worker]   Configures K8s ingress and service to enable web traffic for your service. Please use route trait in cap center for advanced usage.
  5. scaler                                     [webservice worker]   Configures replicas for your service.
  6. sidecar                                    [webservice worker]   inject a sidecar container into your app

正常情况下 TraitDefinition 只能被同 namespace 下的 application 引用，但是 vela-system namespace 下的可以被所有 application 引用。

我们可以用命令 kubectl vela show 查看指定 TraitDefinition 暴露的参数。

  1. $ kubectl vela show sidecar
  2. # Properties
  3. +---------+-----------------------------------------+----------+----------+---------+
  4. |  NAME   |               DESCRIPTION               |   TYPE   | REQUIRED | DEFAULT |
  5. +---------+-----------------------------------------+----------+----------+---------+
  6. | name    | Specify the name of sidecar container   | string   | true     |         |
  7. | image   | Specify the image of sidecar container  | string   | true     |         |
  8. | command | Specify the commands run in the sidecar | []string | false    |         |
  9. +---------+-----------------------------------------+----------+----------+---------+