TNND，我是真的服了，估计玩阿里云集群的兄弟，都会遇到这个个问题。
首先我们来看启动信息：
[root@hadoop101 ~]# clickhouse-client -m ClickHouse client version 20.4.5.36 (official build).Connecting to localhost:9000 as user default.Code: 210、DB::NetException: Connection refused (localhost:9000)
从上面看，完全看不出问题，别信网上说的什么端口占用、进程没关
直接开日志
[root@hadoop101 clickhouse-server]# tail -f clickhouse-server.log
我们截取ERROR日志信息
2022.02.14 17:32:43.642826 [ 2396 ] {} Application: starting up2022.02.14 17:32:43.646257 [ 2396 ] {} Application: rlimit on number of file descriptors is 5000002022.02.14 17:32:43.646274 [ 2396 ] {} Application: Initializing DateLUT.2022.02.14 17:32:43.646282 [ 2396 ] {} Application: Initialized DateLUT with time zone 'Asia/Shanghai'.2022.02.14 17:32:43.646304 [ 2396 ] {} Application: Setting up /var/lib/clickhouse/tmp/ to store temporary data in it2022.02.14 17:32:43.646484 [ 2396 ] {} Application: Configuration parameter 'interserver_http_host' doesn't exist or exists and empty、Will use 'hadoop101' as replica host.2022.02.14 17:32:43.648321 [ 2396 ] {} ConfigReloader: Loading config '/etc/clickhouse-server/users.xml'2022.02.14 17:32:43.649468 [ 2396 ] {} Application: Uncompressed cache size was lowered to 3.75 GiB because the system has low amount of memory2022.02.14 17:32:43.649689 [ 2396 ] {} Application: Mark cache size was lowered to 3.75 GiB because the system has low amount of memory2022.02.14 17:32:43.649726 [ 2396 ] {} Application: Setting max_server_memory_usage was set to 6.75 GiB2022.02.14 17:32:43.649734 [ 2396 ] {} Application: Loading metadata from /var/lib/clickhouse/2022.02.14 17:32:43.651423 [ 2396 ] {} DatabaseOrdinary (system): Total 2 tables and 0 dictionaries.2022.02.14 17:32:43.656837 [ 2401 ] {} BackgroundProcessingPool: Create BackgroundProcessingPool with 16 threads2022.02.14 17:32:43.657703 [ 2401 ] {} system.metric_log: Loading data parts2022.02.14 17:32:43.663843 [ 2401 ] {} system.metric_log: Loaded data parts (2 items)2022.02.14 17:32:43.664195 [ 2401 ] {} system.trace_log: Loading data parts2022.02.14 17:32:43.664937 [ 2401 ] {} system.trace_log: Loaded data parts (3 items)2022.02.14 17:32:43.665026 [ 2396 ] {} DatabaseOrdinary (system): Starting up tables.2022.02.14 17:32:43.665941 [ 2396 ] {} DatabaseOrdinary (default): Total 0 tables and 0 dictionaries.2022.02.14 17:32:43.665958 [ 2396 ] {} DatabaseOrdinary (default): Starting up tables.2022.02.14 17:32:43.666002 [ 2396 ] {} BackgroundSchedulePool/BgSchPool: Create BackgroundSchedulePool with 16 threads2022.02.14 17:32:43.666800 [ 2396 ] {} Application: Loaded metadata.2022.02.14 17:32:43.666835 [ 2396 ] {} Pipe: Pipe capacity is 1.00 MiB2022.02.14 17:32:43.668407 [ 2396 ] {} Application: Shutting down storages.2022.02.14 17:32:43.668460 [ 2420 ] {} SystemLog (system.trace_log): Flushing system log2022.02.14 17:32:43.668545 [ 2420 ] {} SystemLog (system.trace_log): Will use existing table system.trace_log for TraceLog2022.02.14 17:32:43.668793 [ 2420 ] {} DiskLocal: Reserving 1.00 MiB on disk `default`, having unreserved 26.30 GiB.2022.02.14 17:32:43.669562 [ 2420 ] {} system.trace_log: Renaming temporary part tmp_insert_202202_1_1_0 to 202202_19_19_0.2022.02.14 17:32:44.665383 [ 2421 ] {} SystemLog (system.metric_log): Flushing system log2022.02.14 17:32:44.665754 [ 2421 ] {} SystemLog (system.metric_log): Will use existing table system.metric_log for MetricLog2022.02.14 17:32:44.667693 [ 2421 ] {} DiskLocal: Reserving 1.00 MiB on disk `default`, having unreserved 26.30 GiB.2022.02.14 17:32:44.668659 [ 2421 ] {} system.metric_log: Renaming temporary part tmp_insert_202202_1_1_0 to 202202_71_71_0.2022.02.14 17:32:44.669585 [ 2396 ] {} BackgroundSchedulePool/BgSchPool: Waiting for threads to finish.2022.02.14 17:32:44.669831 [ 2396 ] {} Application: Shut down storages.2022.02.14 17:32:44.670359 [ 2396 ] {} Application: Destroyed global context.2022.02.14 17:32:44.670824 [ 2396 ] {} Application: DB::Exception: Listen [::]:8123 failed: Poco::Exception、Code: 1000, e.code() = 0, e.displayText() = DNS error: EAI: -9 (version 20.4.5.36 (official build))2022.02.14 17:32:44.670847 [ 2396 ] {} Application: shutting down2022.02.14 17:32:44.670853 [ 2396 ] {} Application: Uninitializing subsystem: Logging Subsystem2022.02.14 17:32:44.670904 [ 2399 ] {} baseDaemon: Received signal -22022.02.14 17:32:44.670925 [ 2399 ] {} baseDaemon: Stop SignalListener thread
提取关键信息：
2022.02.14 17:32:44.670824 [ 2396 ] {} Application: DB::Exception: Listen [::]:8123 failed: Poco::Exception、Code: 1000, e.code() = 0, e.displayText() = DNS error: EAI: -9 (version 20.4.5.36 (official build))
他说连接不上这个端口，好了，我们一般到这就是去查看端口了，结构netstat一看，没被占用，就迷茫了。
重点：我们看配置文件就知道了
0.0.0.0
从上面我们可以看得到，他说你要是用IPV6网络格式的话，就不能用
::
必须的是
0.0.0.0
改好之后，重启一下就好了，主要原因还是你云服务器没开IPV6，应该是这样吧。