$ ${SOLR_ROOT}/bin/solr healthcheck -help

Usage: solr healthcheck [-c collection] [-z zkHost] [-V]

-c collection
  Collection to run healthcheck against.

-z zkHost
  ZooKeeper connection string; default is localhost:9983

-V
  Enables more verbose output.

$ ${SOLR_ROOT}/bin/solr healthcheck -c collection6 -z "localhost:2181/solr"

Here's the output of running this command on my localhost where I have 2 Solr instances and 1 ZooKeeper instance.

{
    "collection": "collection6",
    "status": "healthy",
    "numDocs": 0,
    "numShards": 2,
    "shards": [
        {
            "shard": "shard1",
            "status": "healthy",
            "replicas": [
                {
                    "name": "core_node3",
                    "url": "http://192.168.2.33:8984/solr/collection6_shard1_replica_n1/",
                    "numDocs": 0,
                    "status": "active",
                    "uptime": "0 days, 0 hours, 24 minutes, 1 seconds",
                    "memory": "219.1 MB (%42.8) of 512 MB"
                },
                {
                    "name": "core_node5",
                    "url": "http://192.168.2.33:8983/solr/collection6_shard1_replica_n2/",
                    "numDocs": 0,
                    "status": "active",
                    "uptime": "0 days, 0 hours, 24 minutes, 20 seconds",
                    "memory": "310.6 MB (%60.7) of 512 MB",
                    "leader": true
                }
            ]
        },
        {
            "shard": "shard2",
            "status": "healthy",
            "replicas": [
                {
                    "name": "core_node7",
                    "url": "http://192.168.2.33:8984/solr/collection6_shard2_replica_n4/",
                    "numDocs": 0,
                    "status": "active",
                    "uptime": "0 days, 0 hours, 24 minutes, 1 seconds",
                    "memory": "220.1 MB (%43) of 512 MB"
                },
                {
                    "name": "core_node8",
                    "url": "http://192.168.2.33:8983/solr/collection6_shard2_replica_n6/",
                    "numDocs": 0,
                    "status": "active",
                    "uptime": "0 days, 0 hours, 24 minutes, 20 seconds",
                    "memory": "311.1 MB (%60.8) of 512 MB",
                    "leader": true
                }
            ]
        }
    ]
}