[root@cmodb801 etc]# service mongos start
Redirecting to /bin/systemctl start mongos.service
[root@cmodb801 etc]#
[root@cmodb801 mongodb]# mongo
MongoDB shell version v4.2.0
connecting to: mongodb://127.0.0.1:27017/?compressors=disabled&gssapiServiceName=mongodb
Implicit session: session { "id" : UUID("363a5deb-abba-4bb2-82ab-1249d7283e20") }
MongoDB server version: 4.2.0
Server has startup warnings:
2019-08-30T11:19:36.768+0000 I  CONTROL  [main]
2019-08-30T11:19:36.768+0000 I  CONTROL  [main] ** WARNING: Access control is not enabled for the database.
2019-08-30T11:19:36.768+0000 I  CONTROL  [main] **          Read and write access to data and configuration is unrestricted.
2019-08-30T11:19:36.768+0000 I  CONTROL  [main]
mongos> sh.addShard("shard0003/cmodb812.togewa.com:27018,cmodb813.togewa.com:27018")
{
        "shardAdded" : "shard0003",
        "ok" : 1,
        "operationTime" : Timestamp(1567163996, 2),
        "$clusterTime" : {
                "clusterTime" : Timestamp(1567163996, 2),
                "signature" : {
                        "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
                        "keyId" : NumberLong(0)
                }
        }
}
mongos> ^C
bye
[root@cmodb801 mongodb]# service mongos restart
Redirecting to /bin/systemctl restart mongos.service
[root@cmodb801 mongodb]# mongo
MongoDB shell version v4.2.0
connecting to: mongodb://127.0.0.1:27017/?compressors=disabled&gssapiServiceName=mongodb
2019-08-30T11:20:10.650+0000 E  QUERY    [js] Error: couldn't connect to server 127.0.0.1:27017, connection attempt failed: SocketException: Error connecting to 127.0.0.1:27017 :: caused by :: Connection refused :
connect@src/mongo/shell/mongo.js:341:17
@(connect):2:6
2019-08-30T11:20:10.653+0000 F  -        [main] exception: connect failed
2019-08-30T11:20:10.653+0000 E  -        [main] exiting with code 1
[root@cmodb801 mongodb]# ^C