ClickHouse High Availability Setup for Spring Boot Applications

December 02, 2025

#1

High availability (HA) ensures your Spring Boot app always works even if one ClickHouse node fails. Let’s set up HA easily.

1. Use Replicated Tables

CREATE TABLE app_logs ON CLUSTER my_cluster (
    id UUID,
    ts DateTime,
    message String
) ENGINE = ReplicatedMergeTree(
    '/clickhouse/tables/{shard}/app_logs', 
    '{replica}'
)
ORDER BY ts;

ReplicatedMergeTree keeps data consistent across nodes.

2. Create a Distributed Table

CREATE TABLE app_logs_dist ON CLUSTER my_cluster AS app_logs
ENGINE = Distributed(my_cluster, default, app_logs, rand());

Apps query this distributed table instead of a single node.

3. Configure Spring Boot

spring:
  datasource:
    url: jdbc:clickhouse://cluster-node:8123/default
    username: default
    password:

Point to a cluster endpoint or load balancer.

4. Load Balancing Queries

ClickHouse JDBC supports multiple hosts:

spring:
  datasource:
    url: jdbc:clickhouse://node1:8123,node2:8123/default

If one node fails, the driver retries others.

5. Insert Data with JdbcTemplate

jdbcTemplate.update(
  "INSERT INTO app_logs_dist (id, ts, message) VALUES (?, ?, ?)",
  UUID.randomUUID(), LocalDateTime.now(), "App started"
);

Data automatically replicates across cluster nodes.