集群健康

    1. {
    2.    "cluster_name":          "elasticsearch",
    3.    "status":                "green", <1>
    4.    "number_of_nodes":       1,
    5.    "number_of_data_nodes":  1,
    6.    "active_primary_shards": 0,
    7.    "relocating_shards":     0,
    8.    "initializing_shards":   0,
    1. status 是我们最应该关注的字段。