Kubernetes中无法删除一个对象，持续处于Terminating状态的解决方案

1. 问题描述

未使用uninstall.yml文件删除longhorn组件的时候，从而造成无法删除longhorn-system名称空间的解决方案

此时使用kubectl delete ns longhorn-system已经无法完成删除操作了。会持续显示terminating的状态

2. 解决方案

此时可以将无法删除且一直处于terminating状态的对象以json格式导出为文件，此处的对象是名为longhorn-system的名称空间。该名称空间导出为json格式，然后然后去掉其中的spec以及status字段信息。

具体如下：

[root@c7u6s5:longhorn]# kubectl get ns longhorn-system -o json > longhron-system.json
[root@c7u6s5:longhorn]# vim longhorn-system.json
[root@c7u6s5:longhorn]# cat longhorn-system.json 
{"apiVersion": "v1","kind": "Namespace","metadata": {"annotations": {"kubectl.kubernetes.io/last-applied-configuration": "{\"apiVersion\":\"v1\",\"kind\":\"Namespace\",\"metadata\":{\"annotations\":{},\"name\":\"longhorn-system\"}}\n"},"creationTimestamp": "2022-03-13T08:48:06Z","deletionTimestamp": "2022-03-21T09:09:02Z","labels": {"kubernetes.io/metadata.name": "longhorn-system"},"name": "longhorn-system","resourceVersion": "13365518","uid": "9182f43a-e302-4fe5-b8b4-b37bde46228a"}
}
[root@c7u6s5:longhorn]# 

上述就是将spec以及status字段去掉之后的内容。

然后启动kubectl proxy代理，通过curl命令直接与api服务器通信，通过@longhorn-system.json语法指定传输上述生成的文件，表示对该文件中的对象执行finalize操作。具体如下：

[root@c7u6s5:longhorn]# curl -k -H 'Content-Type: application/json' -XPUT --data-binary @longhorn-system.json http://127.0.0.1:8001/api/v1/namespaces/longhorn-system/finalize
{
"kind": "Namespace",
"apiVersion": "v1",
"metadata": {"name": "longhorn-system","uid": "9182f43a-e302-4fe5-b8b4-b37bde46228a","resourceVersion": "13365518","creationTimestamp": "2022-03-13T08:48:06Z","deletionTimestamp": "2022-03-21T09:09:02Z","labels": {"kubernetes.io/metadata.name": "longhorn-system"},"annotations": {"kubectl.kubernetes.io/last-applied-configuration": "{\"apiVersion\":\"v1\",\"kind\":\"Namespace\",\"metadata\":{\"annotations\":{},\"name\":\"longhorn-system\"}}\n"},"managedFields": [{"manager": "kubectl-client-side-apply","operation": "Update","apiVersion": "v1","time": "2022-03-13T08:48:06Z","fieldsType": "FieldsV1","fieldsV1": {"f:metadata":{"f:annotations":{".":{},"f:kubectl.kubernetes.io/last-applied-configuration":{}},"f:labels":{".":{},"f:kubernetes.io/metadata.name":{}}}}},{"manager": "kube-controller-manager","operation": "Update","apiVersion": "v1","time": "2022-03-21T09:09:08Z","fieldsType": "FieldsV1","fieldsV1": {"f:status":{"f:conditions":{".":{},"k:{\"type\":\"NamespaceContentRemaining\"}":{".":{},"f:lastTransitionTime":{},"f:message":{},"f:reason":{},"f:status":{},"f:type":{}},"k:{\"type\":\"NamespaceDeletionContentFailure\"}":{".":{},"f:lastTransitionTime":{},"f:message":{},"f:reason":{},"f:status":{},"f:type":{}},"k:{\"type\":\"NamespaceDeletionDiscoveryFailure\"}":{".":{},"f:lastTransitionTime":{},"f:message":{},"f:reason":{},"f:status":{},"f:type":{}},"k:{\"type\":\"NamespaceDeletionGroupVersionParsingFailure\"}":{".":{},"f:lastTransitionTime":{},"f:message":{},"f:reason":{},"f:status":{},"f:type":{}},"k:{\"type\":\"NamespaceFinalizersRemaining\"}":{".":{},"f:lastTransitionTime":{},"f:message":{},"f:reason":{},"f:status":{},"f:type":{}}}}}}]
},
"spec": {},
"status": {"phase": "Terminating","conditions": [{"type": "NamespaceDeletionDiscoveryFailure","status": "False","lastTransitionTime": "2022-03-21T09:27:42Z","reason": "ResourcesDiscovered","message": "All resources successfully discovered"},{"type": "NamespaceDeletionGroupVersionParsingFailure","status": "False","lastTransitionTime": "2022-03-21T09:09:08Z","reason": "ParsedGroupVersions","message": "All legacy kube types successfully parsed"},{"type": "NamespaceDeletionContentFailure","status": "False","lastTransitionTime": "2022-03-21T09:23:09Z","reason": "ContentDeleted","message": "All content successfully deleted, may be waiting on finalization"},{"type": "NamespaceContentRemaining","status": "True","lastTransitionTime": "2022-03-21T09:09:08Z","reason": "SomeResourcesRemain","message": "Some resources are remaining: engineimages.longhorn.io has 1 resource instances, nodes.longhorn.io has 3 resource instances"},{"type": "NamespaceFinalizersRemaining","status": "True","lastTransitionTime": "2022-03-21T09:09:08Z","reason": "SomeFinalizersRemain","message": "Some content in the namespace has finalizers remaining: longhorn.io in 4 resource instances"}]
}
}# 执行晚上述操作之后，longhorn-system名称空间就被删除了。
[root@c7u6s5:longhorn]#curl -k -H 'Content-Type: application/json' -XPUT --data-binary @longhorn-system.json http://127.0.0.1:8001/api/v1/namespaces/longhorn-system/finalize
{
"kind": "Status",
"apiVersion": "v1",
"metadata": {},
"status": "Failure",
"message": "Operation cannot be fulfilled on namespaces \"longhorn-system\": StorageError: invalid object, Code: 4, Key: /registry/namespaces/longhorn-system, ResourceVersion: 0, AdditionalErrorMsg: Precondition failed: UID in precondition: 9182f43a-e302-4fe5-b8b4-b37bde46228a, UID in object meta: ",
"reason": "Conflict",
"details": {"name": "longhorn-system","kind": "namespaces"
},
"code": 409
}[root@c7u6s5:longhorn]#kbuectl get ns
-bash: kbuectl: command not found
[root@c7u6s5:longhorn]# kubectl get ns
NAME                   STATUS   AGE
app-team1              Active   175d
default                Active   230d
kube-node-lease        Active   230d
kube-public            Active   230d
kube-system            Active   230d
kubernetes-dashboard   Active   98m
my-ns                  Active   216d
project-snake          Active   167d
[root@c7u6s5:longhorn]# 

上述的curl命令中的@符号后面的是json文件名称。

上述就完成了longhron-system名称空间的删除操作。