如何使用kubectl通过jsonpath获取输出

Question

我运行kubectl get events以获取事件详细信息，现在我想进行模糊搜索以获取前缀为nginx-*的特定广告连播。>

假设，我的输出如下

$ kubectl get events -o json

{
    "apiVersion": "v1",
    "items": [
        {
            "apiVersion": "v1",
            "count": 1,
            "eventTime": null,
            "firstTimestamp": "2020-03-12T06:18:58Z",
            "involvedObject": {
                "apiVersion": "v1",
                "kind": "Pod",
                "name": "nginx-6db489d4b7-99xmd",
                "namespace": "default",
                "resourceVersion": "9683",
                "uid": "64f6eeb1-c267-4ee1-b34d-14e65573d63f"
            },
            "kind": "Event",
            "lastTimestamp": "2020-03-12T06:18:58Z",
            "message": "Successfully assigned default/nginx-6db489d4b7-99xmd to kind-worker3",
            "metadata": {
                "creationTimestamp": "2020-03-12T06:18:58Z",
                "name": "nginx-6db489d4b7-99xmd.15fb7a182197a184",
                "namespace": "default",
                "resourceVersion": "9703",
                "selfLink": "/api/v1/namespaces/default/events/nginx-6db489d4b7-99xmd.15fb7a182197a184",
                "uid": "de0ff737-e4d6-4218-b441-26c68a1ee8bd"
            },
            "reason": "Scheduled",
            "reportingComponent": "",
            "reportingInstance": "",
            "source": {
                "component": "default-scheduler"
            },
            "type": "Normal"
        },
        {
            "apiVersion": "v1",
            "count": 1,
            "eventTime": null,
            "firstTimestamp": "2020-03-12T06:18:59Z",
            "involvedObject": {
                "apiVersion": "v1",
                "fieldPath": "spec.containers{nginx}",
                "kind": "Pod",
                "name": "nginx-6db489d4b7-99xmd",
                "namespace": "default",
                "resourceVersion": "9693",
                "uid": "64f6eeb1-c267-4ee1-b34d-14e65573d63f"
            },
            "kind": "Event",
            "lastTimestamp": "2020-03-12T06:18:59Z",
            "message": "Pulling image \"nginx\"",
            "metadata": {
                "creationTimestamp": "2020-03-12T06:18:59Z",
                "name": "nginx-6db489d4b7-99xmd.15fb7a18754d0bfc",
                "namespace": "default",
                "resourceVersion": "9709",
                "selfLink": "/api/v1/namespaces/default/events/nginx-6db489d4b7-99xmd.15fb7a18754d0bfc",
                "uid": "d541f134-5e9c-4b7f-b035-ae4d49a3745f"
            },
            "reason": "Pulling",
            "reportingComponent": "",
            "reportingInstance": "",
            "source": {
                "component": "kubelet",
                "host": "kind-worker3"
            },
            "type": "Normal"
        },
        {
            "apiVersion": "v1",
            "count": 1,
            "eventTime": null,
            "firstTimestamp": "2020-03-12T06:18:26Z",
            "involvedObject": {
                "apiVersion": "v1",
                "fieldPath": "spec.containers{nginx}",
                "kind": "Pod",
                "name": "nginx",
                "namespace": "default",
                "resourceVersion": "9555",
                "uid": "f9d0ae86-4d7d-4553-91c2-efc0c3f8144f"
            },
            "kind": "Event",
            "lastTimestamp": "2020-03-12T06:18:26Z",
            "message": "Pulling image \"nginx\"",
            "metadata": {
                "creationTimestamp": "2020-03-12T06:18:26Z",
                "name": "nginx.15fb7a10b4975ae0",
                "namespace": "default",
                "resourceVersion": "9565",
                "selfLink": "/api/v1/namespaces/default/events/nginx.15fb7a10b4975ae0",
                "uid": "f66cf712-1284-4f65-895a-5fbfa974e317"
            },
            "reason": "Pulling",
            "reportingComponent": "",
            "reportingInstance": "",
            "source": {
                "component": "kubelet",
                "host": "kind-worker"
            },
            "type": "Normal"
        },
        {
            "apiVersion": "v1",
            "count": 1,
            "eventTime": null,
            "firstTimestamp": "2020-03-12T06:18:38Z",
            "involvedObject": {
                "apiVersion": "v1",
                "fieldPath": "spec.containers{nginx}",
                "kind": "Pod",
                "name": "nginx",
                "namespace": "default",
                "resourceVersion": "9555",
                "uid": "f9d0ae86-4d7d-4553-91c2-efc0c3f8144f"
            },
            "kind": "Event",
            "lastTimestamp": "2020-03-12T06:18:38Z",
            "message": "Successfully pulled image \"nginx\"",
            "metadata": {
                "creationTimestamp": "2020-03-12T06:18:38Z",
                "name": "nginx.15fb7a13a4aed9fc",
                "namespace": "default",
                "resourceVersion": "9613",
                "selfLink": "/api/v1/namespaces/default/events/nginx.15fb7a13a4aed9fc",
                "uid": "55a4a512-d5c0-41da-ae9c-c1654b6bbdfe"
            },
            "reason": "Pulled",
            "reportingComponent": "",
            "reportingInstance": "",
            "source": {
                "component": "kubelet",
                "host": "kind-worker"
            },
            "type": "Normal"
        }
    ],
    "kind": "List",
    "metadata": {
        "resourceVersion": "",
        "selfLink": ""
    }
}
我只想从nginx-*窗格中获取消息。 

$ kubectl get events -o=jsonpath='{.items[*].involvedObject}'
但是我不确定如何检查名称是否为nginx-*，然后导出其消息

            "involvedObject": {
                "apiVersion": "v1",
                "kind": "Pod",
                "name": "nginx-6db489d4b7-99xmd",
                "namespace": "default",
                "resourceVersion": "9683",
                "uid": "64f6eeb1-c267-4ee1-b34d-14e65573d63f"
            },
            "message": "Successfully assigned default/nginx-6db489d4b7-99xmd to kind-worker3",

我运行kubectl get events以获取事件的详细信息，现在我想进行模糊搜索以获取前缀为nginx- *的特定Pod。假设，我的输出如下$ kubectl get events -o json .. 。

Answer 1

Kubectl jsonpath实现不支持正则表达式匹配，因此仅使用此工具就不可能实现（请看this github issue）。幸运的是，您始终可以使用jq来过滤事件，下面以示例为例。