背景介绍
当前CCE已全面支持Helm v3版本，用户可通过本指南将已创建的v2 release转换成v3 release，从而更好地使用v3的特性。因Helm v3底层相对于Helm v2来说，一些功能已被弃用或重构，因此转换会有一定风险，需转换前进行模拟转换。
该指南参考社区文档：https://github.com/helm/helm-2to3
注意事项：
- Helm v2 release信息存储在configmap中，Helm v3 release信息存储在secrets中。
- 若用户通过前端console操作，在获取实例、更新实例等操作中CCE会自动尝试转换v2模板实例到v3模板实例。若用户仅在后台操作实例，需通过该指南进行转换操作。
转换流程（不使用Helm v3客户端）
步骤 1 在CCE节点上下载helm 2to3 转换插件。
wget https://github.com/helm/helm-2to3/releases/download/v0.10.2/helm-
2to3_0.10.2_linux_amd64.tar.gz
步骤 2 解压插件包。
tar -xzvf helm-2to3_0.10.2_linux_amd64.tar.gz
步骤 3 模拟转换。
以test-convert实例为例，执行以下命令进行转换的模拟。若出现以下提示，说明模拟转换成功。
# ./2to3 convert --dry-run --tiller-out-cluster -s configmaps test-convert
NOTE: This is in dry-run mode, the following actions will not be executed.
Run without --dry-run to take the actions described below:
Release "test-convert" will be converted from Helm v2 to Helm v3.
[Helm 3] Release "test-convert" will be created.
[Helm 3] ReleaseVersion "test-convert.v1" will be created.
步骤 4 执行正式转换。若出现以下提示，说明转换成功。
# ./2to3 convert --tiller-out-cluster -s configmaps test-convert
Release "test-convert" will be converted from Helm v2 to Helm v3.
[Helm 3] Release "test-convert" will be created.
[Helm 3] ReleaseVersion "test-convert.v1" will be created.
[Helm 3] ReleaseVersion "test-convert.v1" created.
[Helm 3] Release "test-convert" created.
Release "test-convert" was converted successfully from Helm v2 to Helm v3.
Note: The v2 release information still remains and should be removed to avoid conflicts with the migrated v3 release.
v2 release information should only be removed using `helm 2to3` cleanup and when all releases have been migrated over.
步骤 5 转换完成后进行v2 release资源的清理，同样先进行模拟清理，成功后正式清理v2 release资源。
模拟清理：
# ./2to3 cleanup --dry-run --tiller-out-cluster -s configmaps --name test-convert
NOTE: This is in dry-run mode, the following actions will not be executed.
Run without --dry-run to take the actions described below:
WARNING: "Release 'test-convert' Data" will be removed.
[Cleanup/confirm] Are you sure you want to cleanup Helm v2 data? [y/N]: y
Helm v2 data will be cleaned up.
[Helm 2] Release 'test-convert' will be deleted.
[Helm 2] ReleaseVersion "test-convert.v1" will be deleted.
正式清理：
# ./2to3 cleanup --tiller-out-cluster -s configmaps --name test-convert
WARNING: "Release 'test-convert' Data" will be removed.
[Cleanup/confirm] Are you sure you want to cleanup Helm v2 data? [y/N]: y
Helm v2 data will be cleaned up.
[Helm 2] Release 'test-convert' will be deleted.
[Helm 2] ReleaseVersion "test-convert.v1" will be deleted.
[Helm 2] ReleaseVersion "test-convert.v1" d
转换流程（使用Helm v3客户端）
步骤 1 安装Helm v3客户端，参见安装Helm v3。
步骤 2 安装转换插件。
# helm plugin install https://github.com/helm/helm-2to3
Downloading and installing helm-2to3 v0.10.2 ...
https://github.com/helm/helm-2to3/releases/download/v0.10.2/helm-2to3_0.10.2_linux_amd64.tar.gz
Installed plugin: 2to3
步骤 3 查看已安装的插件，确认插件已安装。
# helm plugin list
NAME VERSION DESCRIPTION
2to3 0.10.2 migrate and cleanup Helm v2 configuration and releases in-place to Helm v3
步骤 4 模拟转换。
以test-convert实例为例，执行以下命令进行转换的模拟。若出现以下相关提示，说明模拟转换成功。
# helm 2to3 convert --dry-run --tiller-out-cluster -s configmaps test-convert
NOTE: This is in dry-run mode, the following actions will not be executed.
Run without --dry-run to take the actions described below:
Release "test-convert" will be converted from Helm v2 to Helm v3.
[Helm 3] Release "test-convert" will be created.
[Helm 3] ReleaseVersion "test-convert.v1" will be created.
步骤 5 执行正式转换。若出现以下提示，说明转换成功。
# helm 2to3 convert --tiller-out-cluster -s configmaps test-convert
Release "test-convert" will be converted from Helm v2 to Helm v3.
[Helm 3] Release "test-convert" will be created.
[Helm 3] ReleaseVersion "test-convert.v1" will be created.
[Helm 3] ReleaseVersion "test-convert.v1" created.
[Helm 3] Release "test-convert" created.
Release "test-convert" was converted successfully from Helm v2 to Helm v3.
Note: The v2 release information still remains and should be removed to avoid conflicts with the migrated v3 release.
v2 release information should only be removed using `helm 2to3` cleanup and when all releases have been migrated over.
步骤 6 正式转换成功后，用户可通过helm list查看已转换成功的模板实例。
# helm list
NAME NAMESPACE REVISION UPDATED STATUS CHART APP VERSION
test-convert default 1 2022-08-29 06:56:28.166918487 +0000 UTC deployed test-helmold-1
步骤 7 转换完成后进行V2 release资源的清理，同样先进行模拟清理，成功后正式清理V2 release资源。
模拟清理：
# helm 2to3 cleanup --dry-run --tiller-out-cluster -s configmaps --name test-convert
NOTE: This is in dry-run mode, the following actions will not be executed.
Run without --dry-run to take the actions described below:
WARNING: "Release 'test-convert' Data" will be removed.
[Cleanup/confirm] Are you sure you want to cleanup Helm v2 data? [y/N]: y
Helm v2 data will be cleaned up.
[Helm 2] Release 'test-convert' will be deleted.
[Helm 2] ReleaseVersion "test-convert.v1" will be deleted.
正式清理：
# helm 2to3 cleanup --tiller-out-cluster -s configmaps --name test-convert
WARNING: "Release 'test-convert' Data" will be removed.
[Cleanup/confirm] Are you sure you want to cleanup Helm v2 data? [y/N]: y
Helm v2 data will be cleaned up.
[Helm 2] Release 'test-convert' will be deleted.
[Helm 2] ReleaseVersion "test-convert.v1" will be deleted.
[Helm 2] ReleaseVersion "test-convert.v1" deleted.
[Helm 2] Release 'test-convert' deleted.
Helm v2 data was cleaned up successfully.
