bash - 命名路径的 kubectl jsonpath 表达式

Question

我有 kube 服务运行 2 个命名端口，如下所示:

$ kubectl get service elasticsearch --output json
{
    "apiVersion": "v1",
    "kind": "Service",
    "metadata": {
        ... stuff that really has nothing to do with my question ...
    },
    "spec": {
        "clusterIP": "10.0.0.174",
        "ports": [
             {
                "name": "http",
                "nodePort": 31041,
                "port": 9200,
                "protocol": "TCP",
                "targetPort": 9200
            },
            {
                "name": "transport",
                "nodePort": 31987,
                "port": 9300,
                "protocol": "TCP",
                "targetPort": 9300
            }
        ],
        "selector": {
            "component": "elasticsearch"
        },
        "sessionAffinity": "None",
        "type": "NodePort"
    },
    "status": {
        "loadBalancer": {}
    }
}

我正在尝试获取仅包含“http”端口的输出:

$ kubectl get service elasticsearch --output jsonpath={.spec.ports[*].nodePort}
31041 31987

除非我在此处的备忘单中添加了测试表达式 http://kubernetes.io/docs/user-guide/kubectl-cheatsheet/对于名称，我收到错误消息

$ kubectl get service elasticsearch --output jsonpath={.spec.ports[?(@.name=="http")].nodePort}
-bash: syntax error near unexpected token `('

Answer 1

(和 )在 bash 中表示某些东西(请参阅 subshell )，因此您的 shell 解释器首先执行此操作并感到困惑。将参数包装到 jsonpath在单引号中，这将解决它:

$ kubectl get service elasticsearch --output jsonpath='{.spec.ports[?(@.name=="http")].nodePort}'

例如:

# This won't work:
$ kubectl get service kubernetes --output jsonpath={.spec.ports[?(@.name=="https")].targetPort}
-bash: syntax error near unexpected token `('

# ... but this will:
$ kubectl get service kubernetes --output jsonpath='{.spec.ports[?(@.name=="https")].targetPort}'
443