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# 对使用 PersistentVolumeClaims (PVC) 的作业进行故障排除
<a name="permissions-for-pvc"></a>

如果你需要为任务创建、列出或删除 PersistentVolumeClaims (PVC)，但不向默认 Kubernetes 角色 *emr-* containers 添加 PVC 权限，那么当你提交任务时，任务就会失败。如果没有这些权限，则 *emr-containers* 角色无法为 Spark 驱动程序或 Spark 客户端创建必要的角色。如错误消息所示，向 Spark 驱动程序或客户端角色添加权限是不够的。*emr-containers* 主角色还必须包括所需的权限。本节介绍如何向 *emr-containers* 主角色添加所需的权限。

## 验证
<a name="verification"></a>

要验证您的 *emr-containers* 角色是否具有必要的权限，请使用您自己的值设置 NAMESPACE 变量，然后运行以下命令：

```
export NAMESPACE=YOUR_VALUE
kubectl describe role emr-containers -n ${NAMESPACE}
```

此外，若要验证 Spark 和客户端角色是否具有必要的权限，请运行以下命令：

```
kubectl describe role emr-containers-role-spark-driver -n ${NAMESPACE}
kubectl describe role emr-containers-role-spark-client -n ${NAMESPACE}
```

如果没有权限，请按如下方式继续修补。

## 修补
<a name="patch"></a>

1. 如果没有权限的作业当前正在运行，则停止这些作业。

1. 创建名为 *RBAC\_Patch.py* 的文件，如下所示：

   ```
   import os
   import subprocess as sp
   import tempfile as temp
   import json
   import argparse
   import uuid
   
   def delete_if_exists(dictionary: dict, key: str):
       if dictionary.get(key, None) is not None:
           del dictionary[key]
   
   def doTerminalCmd(cmd):
       with temp.TemporaryFile() as f:
           process = sp.Popen(cmd, stdout=f, stderr=f)
           process.wait()
           f.seek(0)
           msg = f.read().decode()
       return msg
   
   def patchRole(roleName, namespace, extraRules, skipConfirmation=False):
       cmd = f"kubectl get role {roleName} -n {namespace} --output json".split(" ")
       msg = doTerminalCmd(cmd)
       if "(NotFound)" in msg and "Error" in msg:
           print(msg)
           return False
       role = json.loads(msg)
       rules = role["rules"]
       rulesToAssign = extraRules[::]
       passedRules = []
       for rule in rules:
           apiGroups = set(rule["apiGroups"])
           resources = set(rule["resources"])
           verbs = set(rule["verbs"])
           for extraRule in extraRules:
               passes = 0
               apiGroupsExtra = set(extraRule["apiGroups"])
               resourcesExtra = set(extraRule["resources"])
               verbsExtra = set(extraRule["verbs"])
               passes += len(apiGroupsExtra.intersection(apiGroups)) >= len(apiGroupsExtra)
               passes += len(resourcesExtra.intersection(resources)) >= len(resourcesExtra)
               passes += len(verbsExtra.intersection(verbs)) >= len(verbsExtra)
               if passes >= 3:
                   if extraRule not in passedRules:
                       passedRules.append(extraRule)
                       if extraRule in rulesToAssign:
                           rulesToAssign.remove(extraRule)
                   break
       prompt_text = "Apply Changes?"
       if len(rulesToAssign) == 0:
           print(f"The role {roleName} seems to already have the necessary permissions!")
           prompt_text = "Proceed anyways?"
       for ruleToAssign in rulesToAssign:
           role["rules"].append(ruleToAssign)
       delete_if_exists(role, "creationTimestamp")
       delete_if_exists(role, "resourceVersion")
       delete_if_exists(role, "uid")
       new_role = json.dumps(role, indent=3)
       uid = uuid.uuid4()
       filename = f"Role-{roleName}-New_Permissions-{uid}-TemporaryFile.json"
       try:
           with open(filename, "w+") as f:
               f.write(new_role)
               f.flush()
           prompt = "y"
           if not skipConfirmation:
               prompt = input(
                   doTerminalCmd(f"kubectl diff -f {filename}".split(" ")) + f"\n{prompt_text} y/n: "
               ).lower().strip()
               while prompt != "y" and prompt != "n":
                   prompt = input("Please make a valid selection. y/n: ").lower().strip()
           if prompt == "y":
               print(doTerminalCmd(f"kubectl apply -f {filename}".split(" ")))
       except Exception as e:
           print(e)
       os.remove(f"./{filename}")
   
   if __name__ == '__main__':
       parser = argparse.ArgumentParser()
       parser.add_argument("-n", "--namespace",
                           help="Namespace of the Role. By default its the VirtualCluster's namespace",
                           required=True,
                           dest="namespace"
                           )
   
       parser.add_argument("-p", "--no-prompt",
                           help="Applies the patches without asking first",
                           dest="no_prompt",
                           default=False,
                           action="store_true"
                           )
       args = parser.parse_args()
   
       emrRoleRules = [
           {
               "apiGroups": [""],
               "resources": ["persistentvolumeclaims"],
               "verbs": ["list", "create", "delete", "patch"]
            }
           
       ]
   
       driverRoleRules = [
           {
               "apiGroups": [""],
               "resources": ["persistentvolumeclaims"],
               "verbs": ["list", "create", "delete", "patch", "deletecollection"]
           },
           {
               "apiGroups": [""],
               "resources": ["services"],
               "verbs": ["get", "list", "describe", "create", "delete", "watch", "deletecollection"]
           },
           {
               "apiGroups": [""],
               "resources": ["configmaps", "pods"],
               "verbs": ["deletecollection"]
           }
       ]
   
       clientRoleRules = [
           {
               "apiGroups": [""],
               "resources": ["persistentvolumeclaims"],
               "verbs": ["list", "create", "delete", "patch"]
           }
       ]
   
       patchRole("emr-containers", args.namespace, emrRoleRules, args.no_prompt)
       patchRole("emr-containers-role-spark-driver", args.namespace, driverRoleRules, args.no_prompt)
       patchRole("emr-containers-role-spark-client", args.namespace, clientRoleRules, args.no_prompt)
   ```

1. 运行 Python 脚本：

   ```
   python3 RBAC_Patch.py -n ${NAMESPACE}
   ```

1. 显示新权限和旧权限之间的 kubectl 差异。按 y 以修补角色。

1. 使用附加权限验证三个角色，如下所示：

   ```
   kubectl describe role -n ${NAMESPACE}
   ```

1. 运行 Python 脚本：

   ```
   python3 RBAC_Patch.py -n ${NAMESPACE}
   ```

1. 运行命令后，将显示新旧权限之间的 kubectl 差异。按 y 以修补角色。

1. 使用附加权限验证三个角色：

   ```
   kubectl describe role -n ${NAMESPACE}
   ```

1. 再次提交作业。

## 手动修补
<a name="manual-patch"></a>

如果您的应用程序所需的权限适用于 PVC 规则以外的其他内容，您可以根据需要为 Amazon EMR 虚拟集群手动添加 Kubernetes 权限。

**注意**  
角色 *emr-containers* 是主要角色。这意味着它必须提供所有必要的权限，然后您才能更改底层驱动程序或客户端角色。

1. 通过运行以下命令将当前权限下载到 yaml 文件：

   ```
   kubectl get role -n ${NAMESPACE} emr-containers -o yaml >> emr-containers-role-patch.yaml
   kubectl get role -n ${NAMESPACE} emr-containers-role-spark-driver -o yaml >> driver-role-patch.yaml
   kubectl get role -n ${NAMESPACE} emr-containers-role-spark-client -o yaml >> client-role-patch.yaml
   ```

1. 根据应用程序所需的权限，编辑每个文件并添加其他规则，如下所示：
   + emr-containers-role-patch.yaml

     ```
     - apiGroups:
       - ""
       resources:
       - persistentvolumeclaims
       verbs:
       - list
       - create
       - delete
       - patch
     ```
   + driver-role-patch.yaml

     ```
     - apiGroups:
       - ""
       resources:
       - persistentvolumeclaims
       verbs:
       - list
       - create
       - delete
       - patch
       - deletecollection
     - apiGroups:
       - ""
       resources:
       - services
       verbs:
       - get 
       - list 
       - describe 
       - create
       - delete 
       - watch
       - deletecollection
     - apiGroups:
       - ""
       resources:
       - configmaps
       - pods
       verbs:
       - deletecollection
     ```
   + client-role-patch.yaml

     ```
     - apiGroups:
       - ""
       resources:
       - persistentvolumeclaims
       verbs:
       - list
       - create
       - delete
       - patch
     ```

1. 删除以下属性及其值。这是应用更新所必需的。
   + creationTimestamp
   + resourceVersion
   + uid

1. 最后，运行补丁：

   ```
   kubectl apply -f emr-containers-role-patch.yaml
   kubectl apply -f driver-role-patch.yaml
   kubectl apply -f client-role-patch.yaml
   ```