ClickHouse之集群搭建以及數據復制
阿新 • • 發佈：2019-05-16
區別 could 創建配置文件 以及 fault replicas text 關系 exc
Values for substitutions are specified in /yandex/name_of_substitution elements in that file.
【復制數據需要zookeeper配合】
環境：
1. 3臺機器，我這裏是3臺虛擬機。都安裝了clickhouse。
2. 綁定hosts，其實不綁定也沒關系，配置文件裏面直接寫ip。（3臺機器都綁定hosts，如下）
192.168.0.10 db_server_yayun_01 192.168.0.20 db_server_yayun_02 192.168.0.30 db_server_yayun_03
3. 創建配置文件，默認這個配置文件是不存在的。/etc/clickhouse-server/config.xml有提示，如下：
If element has ‘incl‘ attribute, then for it‘s value will be used corresponding substitution from another file.
Values for substitutions are specified in /yandex/name_of_substitution elements in that file.
配置文件/etc/metrika.xml內容如下：
<yandex>
<clickhouse_remote_servers>
<perftest_3shards_1replicas>
<shard>
<internal_replication>true</internal_replication>
<replica>
<host>db_server_yayun_01</host>
<port>9000</port>
</replica>
</shard>
<shard>
<replica>
<internal_replication>true</internal_replication>
<host>db_server_yayun_02</host>
<port>9000</port>
</replica>
</shard>
<shard>
<internal_replication>true</internal_replication>
<replica>
<host>db_server_yayun_03</host>
<port>9000</port>
</replica>
</shard>
</perftest_3shards_1replicas>
</clickhouse_remote_servers>
<zookeeper-servers>
<node index="1">
<host>192.168.0.30</host>
<port>2181</port>
</node>
</zookeeper-servers>
<macros>
<replica>192.168.0.10</replica>
</macros>
<networks>
<ip>::/0</ip>
</networks>
<clickhouse_compression>
<case>
</clickhouse_compression>
</yandex>
3臺機器的配置文件都一樣，唯一有區別的是：
<macros>
<replica>192.168.0.10</replica>
</macros>服務器ip是多少這裏就寫多少，其實不寫ip也沒關系，3臺機器不重復就行。這裏是復制需要用到的配置。還有zk的配置如下：
<zookeeper-servers>
<node index="1">
<host>192.168.0.30</host>
<port>2181</port>
</node>
</zookeeper-servers>
我的zk是安裝在30的機器上面的，只安裝了一個實例，生產環境肯定要放到單獨的機器，並且配置成集群。配置文件修改好以後3臺服務器重啟。
官方文檔給的步驟是：
ClickHouse deployment to cluster ClickHouse cluster is a homogenous cluster. Steps to set up: 1. Install ClickHouse server on all machines of the cluster 2. Set up cluster configs in configuration file 3. Create local tables on each instance 4. Create a Distributed table
前面2步都搞定了，下面創建本地表，再創建Distributed表。（3臺機器都創建，DDL不同步，蛋疼）
CREATE TABLE ontime_local (FlightDate Date,Year UInt16) ENGINE = MergeTree(FlightDate, (Year, FlightDate), 8192); CREATE TABLE ontime_all AS ontime_local ENGINE = Distributed(perftest_3shards_1replicas, default, ontime_local, rand())
插入數據（隨便一臺機器就行）：
:) insert into ontime_all (FlightDate,Year)values(‘2001-10-12‘,2001); INSERT INTO ontime_all (FlightDate, Year) VALUES Ok. 1 rows in set. Elapsed: 0.013 sec. :) insert into ontime_all (FlightDate,Year)values(‘2002-10-12‘,2002); INSERT INTO ontime_all (FlightDate, Year) VALUES Ok. 1 rows in set. Elapsed: 0.004 sec. :) insert into ontime_all (FlightDate,Year)values(‘2003-10-12‘,2003); INSERT INTO ontime_all (FlightDate, Year) VALUES Ok.
我這裏插入了3條數據。下面查詢看看（任何一臺機器都可以）：
:) select * from ontime_all; SELECT * FROM ontime_all ┌─FlightDate─┬─Year─┐ │ 2001-10-12 │ 2001 │ └────────────┴──────┘ ┌─FlightDate─┬─Year─┐ │ 2002-10-12 │ 2002 │ └────────────┴──────┘ ┌─FlightDate─┬─Year─┐ │ 2003-10-12 │ 2003 │ └────────────┴──────┘ → Progress: 3.00 rows, 12.00 B (48.27 rows/s., 193.08 B/s.) 3 rows in set. Elapsed: 0.063 sec. :)
當在其中一臺機器上面查詢的時候，抓包其他機器可以看見是有請求的。
tcpdump -i any -s 0 -l -w - dst port 9000
那麽關閉其中一臺機器呢？
:) select * from ontime_all; SELECT * FROM ontime_all ┌─FlightDate─┬─Year─┐ │ 2001-10-12 │ 2001 │ └────────────┴──────┘ ┌─FlightDate─┬─Year─┐ │ 2002-10-12 │ 2002 │ └────────────┴──────┘ ┌─FlightDate─┬─Year─┐ │ 2003-10-12 │ 2003 │ └────────────┴──────┘ ↓ Progress: 6.00 rows, 24.00 B (292.80 rows/s., 1.17 KB/s.) Received exception from server: Code: 279. DB::Exception: Received from localhost:9000, ::1. DB::NetException. DB::NetException: All connection tries failed. Log: Code: 210, e.displayText() = DB::NetException: Connection refused: (db_server_yayun_02:9000, 192.168.0.20), e.what() = DB::NetException Code: 210, e.displayText() = DB::NetException: Connection refused: (db_server_yayun_02:9000, 192.168.0.20), e.what() = DB::NetException Code: 210, e.displayText() = DB::NetException: Connection refused: (db_server_yayun_02:9000, 192.168.0.20), e.what() = DB::NetException
可以看見已經拋錯了，竟然不是高可用？後面又看到了文檔的另外一種配置方法，那就是配置2個節點，副本2個，經過測試高可用沒有問題，另外也是分布式並行查詢。感興趣的同學可以自行測試。
https://clickhouse.yandex/reference_en.html#Distributed
下面進行數據復制的測試,zk已經配置好了，直接建表測試（3臺機器都創建）：
CREATE TABLE ontime_replica (FlightDate Date,Year UInt16) ENGINE = ReplicatedMergeTree(‘/clickhouse_perftest/tables/ontime_replica‘,‘{replica}‘,FlightDate,(Year, FlightDate),8192);
插入數據測試：
insert into ontime_replica (FlightDate,Year)values(‘2018-10-12‘,2018);
任何一臺機器均可查詢到。其實到現在對於集群和復制都還沒徹底搞明白，因為分布式表也進行了數據復制，所以有點懵。有大嬸的話歡迎一起交流。
參考資料：
https://clickhouse.yandex/reference_en.html#Distributed
https://clickhouse.yandex/tutorial.html
ClickHouse之集群搭建以及數據復制