Resource relationships in Managed Service for ClickHouse®
The main entity used in the Managed Service for ClickHouse® service is a database cluster.
Each cluster consists of one or more database hosts, which are virtual machines with DBMS servers deployed on them. Cluster hosts may reside in different availability zones and even different availability regions. You can learn more about Yandex Cloud availability zones here.
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A cluster consisting of multiple hosts supports automatic failover, as each host can take the cluster's primary replica role.
When creating such a cluster, choose one of the available options to ensure replication:
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ClickHouse® Keeper:
The cluster will consist only of ClickHouse® hosts.
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ZooKeeper:
The cluster will consist of ClickHouse® hosts and individual ZooKeeper hosts.
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A single-host cluster is not fault tolerant.
You can add ZooKeeper hosts to this cluster later to enable fault tolerance and replication. This will allow you to add multiple ClickHouse® hosts to the cluster.
ClickHouse® Keeper or ZooKeeper hosts manage replication and query distribution across cluster hosts. To learn more, see Replication.
When creating a cluster, specify:
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Host class: VM template for deploying the cluster hosts. For a list of available host classes and their specs, see Host classes.
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Environment: Environment where the cluster will be deployed:
PRODUCTION: For stable versions of your apps.PRESTABLE: For testing purposes. The prestable environment is similar to the production environment and likewise covered by the SLA, but it is the first to get new functionalities, improvements, and bug fixes. In the prestable environment, you can test compatibility of new versions with your application.
You should also specify the host class when creating a shard.
A cluster created in a folder can be accessed by all VMs connected to the same cloud network. For more information about networking, see the Virtual Private Cloud documentation.
Alert
The service can automatically access the system and diagnostic information of your databases to build monitoring charts and maintain your cluster health. The service never queries or uses the data you saved to the database.
ClickHouse® is a registered trademark of ClickHouse, Inc.