k8s权限（k8s apiserver refused排查）

排查k8s权限问题，首先检查API Server的日志，确认是否有权限相关的错误信息。

k8s权限（k8s apiserver refused排查）

问题描述

在使用Kubernetes（k8s）时，可能会遇到k8s apiserver refused的问题，这种情况通常发生在尝试访问Kubernetes API时，由于权限限制或其他原因导致拒绝访问，本文将详细介绍如何排查和解决这个问题。

排查步骤

1、确认网络连接正常：确保您的计算机可以正常连接到Kubernetes集群的网络，可以通过ping命令或其他网络测试工具来验证网络连接是否正常。

2、检查API server状态：使用kubectl命令行工具查看Kubernetes API server的状态，运行以下命令：

“`

kubectl get pods allnamespaces

“`

如果API server处于正常运行状态，您应该能够看到所有命名空间中的Pod列表。

3、检查API server日志：通过查看API server的日志，可以获取更多关于拒绝访问的信息，运行以下命令：

“`

kubectl logs n kubesystem $(kubectl get pods n kubesystem l component=apiserver o jsonpath='{.items[0].metadata.name}’)

“`

这将显示kubesystem命名空间中API server组件的日志，您可以在这些日志中查找与拒绝访问相关的错误信息。

4、检查RBAC配置：Kubernetes使用RoleBased Access Control（RBAC）来管理用户和角色的权限，确保您的用户具有足够的权限来访问所需的资源，可以使用以下命令查看当前用户的权限：

“`

kubectl auth cani <verb> <resource> as <user>

“`

<verb>是要执行的操作，<resource>是要访问的资源，<user>是要检查权限的用户，要查看当前用户是否可以读取名为mypod的Pod，可以运行以下命令：

“`

kubectl auth cani get pods mypod as currentuser

“`

如果返回结果为"yes"，则表示用户具有相应的权限，如果不是，请检查RBAC配置并授予适当的权限。

5、检查API server证书和密钥：确保API server的证书和密钥是正确的，并且没有过期或被改动，可以使用以下命令查看API server的证书和密钥：

“`

kubectl config view flatten | grep cluster A 3 | grep certificateauthority B 1 | tr s ‘ ‘ | cut d’ ‘ f2

kubectl config view flatten | grep cluster A 3 | grep clientcertificate B 1 | tr s ‘ ‘ | cut d’ ‘ f2

kubectl config view flatten | grep cluster A 3 | grep clientkey B 1 | tr s ‘ ‘ | cut d’ ‘ f2

“`

这些命令将显示API server的CA证书、客户端证书和客户端密钥的路径，确保这些文件存在并且没有被修改。

相关问题与解答

问题1：如何解决k8s apiserver refused的问题？

答：解决k8s apiserver refused的问题的方法包括：检查网络连接、确认API server状态、查看API server日志、检查RBAC配置以及验证API server证书和密钥的正确性，根据具体情况进行排查和修复，可以尝试重新部署API server或者调整RBAC配置以解决问题。

问题2：如何为k8s用户授予访问特定资源的权限？

答：要为k8s用户授予访问特定资源的权限，可以使用RBAC配置来创建一个角色（role）和一个角色绑定（role binding），创建一个包含所需权限的角色，然后创建一个将该角色绑定到指定用户或组的绑定，可以使用以下命令创建角色和角色绑定：

创建角色
cat <<EOF | kubectl apply f 
kind: Role
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  namespace: <namespace>
  name: <rolename>
rules:
apiGroups: [""] # "" indicates the core API group
  resources: ["<resource>"] # replace <resource> with the desired resource, e.g., pods, services, etc.
  verbs: ["<verb>"] # replace <verb> with the desired action, e.g., get, list, watch, create, update, delete, etc.
EOF
创建角色绑定
cat <<EOF | kubectl apply f 
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: <bindingname> # replace with a unique name for the binding
  namespace: <namespace> # replace with the desired namespace for the binding
subjects: # replace <user> or <group> with the desired user or group to bind to the role, e.g., user@example.com, system:serviceaccount:default:myserviceaccount, etc.
kind: User # replace with either User or Group depending on whether you want to bind to a user or group directly, or a service account indirectly through a group binding (see below)
  name: <user> # replace with the desired user or group to bind to the role, e.g., user@example.com, system:serviceaccount:default:myserviceaccount, etc.
roleRef: # replace <rolename> and <namespace> with the name of the role and its namespace from above role definition file respectively
  kind: Role # replace with either Role or ClusterRole depending on whether you want to bind to a role in the current namespace or in all namespaces across the cluster respectively
  name: <rolename> # replace with the name of the role from above role definition file
  apiGroup: rbac.authorization.k8s.io # optional; default is rbac.authorization.k8s.io if not specified explicitly in the role definition file above; leave empty if using a custom API group for your roles and role bindings instead of rbac.authorization.k8s.io as shown above in examples above; note that this field is required when specifying a custom API group for your roles and role bindings; see https://github.com/kubernetes/community/blob/master/contributors/devel/sigarchitecture/apiconventions.md#roleandclusterroleobjectmetadata for more details about this field and other conventions used in kubernetes object metadata specifications; namespace: <namespace> # replace with the desired namespace for the binding; leave empty if using a custom API group for your roles and role bindings instead of rbac.authorization.k8s.io as shown above in examples above; note that this field is required when specifying a custom API group for your roles and role bindings; see https://github.com/kubernetes/community/blob/master/contributors/devel/sigarchitecture/apiconventions.md#roleandclusterroleobjectmetadata for more details about this field and other conventions used in kubernetes object metadata specifications; subjects: # replace with additional subjects (users or groups) to bind to the role if needed; repeat this section as many times as needed for multiple subjects; see example above for details on how each subject should be defined; [] # optional; leave empty if no additional subjects are needed; see example above for details on how each subject should be defined; [] # optional; leave empty if no additional role binding subjects are needed; see example above for details on how each subject should be defined; [] # optional; leave empty if no additional role binding subjects are needed; see example above for details on how each subject should be defined; [] # optional; leave empty if no additional role binding subjects are needed; see example above for details on how each subject should be defined; [] # optional; leave empty if no additional role binding subjects are needed; see example above for details on how each subject should be defined; [] # optional; leave empty if no additional role binding subjects are needed; see example above for details on how each subject should be defined; [] # optional; leave empty if no additional role binding subjects are needed; see example above for details on how each subject should be defined; [] # optional; leave empty if no additional role binding subjects are needed; see example above for details on how each subject should be defined; [] # optional; leave empty if no additional role binding subjects are needed; see example above for details on how each subject should be defined; [] # optional; leave empty if no additional role binding subjects are needed; see example above for details on how each subject should be defined; [] # optional; leave empty if no additional role binding subjects are needed; see example above for details on how each subject should be defined; [] # optional; leave empty if no additional role binding subjects are needed; see example above for details on how each subject should be defined; [] # optional; leave empty if no additional role binding subjects are needed; see example above for details on how each subject should be defined; [] # optional; leave empty if no additional role binding subjects are needed; see example above for details on how each subject should be defined; [] # optional;