# clickhouse-cluster # Some Essential checks ## Check keeper : echo ruok | nc 127.0.0.1 9181 sudo systemctl restart clickhouse-keeper Check cluster SELECT \* FROM system.clusters WHERE cluster='default'; # Additional Keeper tests ### **Cluster monitoring**
`echo mntr | nc 127.0.0.1 9181`
Should show:
`zk_server_state leader (on one node)zk_server_state follower (on other two nodes)`
### **Server stats**
`echo stat | nc 127.0.0.1 9181`
### **List znodes**
`echo ls / | nc 127.0.0.1 9181`
# Create db and replicated tables # **Build Replicated ClickHouse Tables** Keeper is fully working. Now you can create **replicated database + replicated tables** that sync across all 3 servers. --- # ๐Ÿš€ Step-by-step instructions (copy/paste) ## 1. Create database on all nodes:
`CREATE DATABASE replicated_db;`
## 2. Create table with replication ### Node1:
`CREATE TABLE replicated_db.events( id UInt64, msg String)ENGINE = ReplicatedMergeTree('/clickhouse/tables/events', 'replica1')ORDER BY id;`
### Node2:
`CREATE TABLE replicated_db.events( id UInt64, msg String)ENGINE = ReplicatedMergeTree('/clickhouse/tables/events', 'replica2')ORDER BY id;`
### Node3:
`CREATE TABLE replicated_db.events( id UInt64, msg String)ENGINE = ReplicatedMergeTree('/clickhouse/tables/events', 'replica3')ORDER BY id;`
--- # ๐Ÿงช Test replication: Insert into Node1:
`INSERT INTO replicated_db.events VALUES (1, 'hello');`
Check on Node2:
`SELECT * FROM replicated_db.events;`
Check on Node3:
`SELECT * FROM replicated_db.events;`
You will see:
`1 | hello`
# New Page CREATE TABLE my\_table ON CLUSTER default ( `id` UInt64, `name` String, `created\_at` String ) ENGINE = MergeTree ORDER BY id INSERT INTO demo.my\_table (id, name, created\_at) VALUES(0, '228', ''); select \* from my\_table INSERT INTO demo.my\_table\_all (id, name, created\_at) VALUES(0, 'X', ''); CREATE TABLE my\_table\_all ON CLUSTER default AS my\_table ENGINE = Distributed(default, demo, my\_table, rand()) select \* from my\_table\_all