spark-submit无法读取属性文件

Question

我正在尝试从Kubernetes窗格运行spark-submit命令。该属性文件作为configmap挂载。这是Pod的json文件：

    "apiVersion": "v1",
    "kind": "Pod",
    "metadata": {
        "name": "spark-submit-pod",
        "labels": {
            "app": "myapp"
        }
    },
    "spec": {
        "serviceAccountName": "spark",
        "volumes": [
            {
                "name": "prop-volume",
                "configMap": {
                    "name": "prop"
                }
            },
            {
                "name": "pem-volume",
                "configMap": {
                    "name": "pem"
                }
            }
        ],
        "imagePullSecrets": [
            {
                "name": "<name of secret>"
            }
        ],
        "containers": [
            {
                "name": "test-container",
                "image": "<image>",
                "volumeMounts": [
                    {
                        "mountPath": "/etc/config",
                        "name": "pem-volume"
                    },
                    {
                        "mountPath": "/etc/prop",
                        "name": "prop-volume"
                    }
                ],
                "command": [
                    "/opt/spark/bin/spark-submit",
                    "--name",
                    "SparkPi",
                    "--deploy-mode",
                    "cluster",
                    "--master",
                    "k8s://<path to k8s cluster>,
                    "--class",
                    "org.apache.spark.examples.SparkPi",
                    "/opt/spark/examples/jars/spark-examples_2.11-2.4.0.jar",
                    "--properties-file=/etc/prop/properties.conf"
                ]
            }
        ],
        "restartPolicy": "Never"
    }
} 

使用多个--conf通过命令部署同一Pod时，spark-submit提交成功。但是上面的命令在pod的日志中给出了以下错误：

Exception in thread "main" org.apache.spark.SparkException: Must specify the driver container image

属性文件确实包含spark.kubernetes.container.image，并且可以访问（尝试了cat命令）。