ClickHouse

ClickHouse is a column-oriented analytical database designed for fast and efficient queries. This page describes the configuration options available for ClickHouse, including backup management.

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Configuration Example

Here is a YAML configuration example for a ClickHouse cluster with two replicas per shard, custom storage size, and enabled backups:

apiVersion: apps.cozystack.io/v1alpha1
kind: ClickHouse
metadata:
  name: clickhouse-example
spec:
  size: 20Gi
  logStorageSize: 5Gi
  shards: 2
  replicas: 2
  storageClass: "replicated"
  logTTL: 30
  users:
    user1:
      password: "securepassword"
    user2:
      readonly: true
      password: "readonlypassword"
  backup:
    enabled: false
  #  s3Region: "hikube"
  #  s3Bucket: "s3.tenant.hikube.cloud/clickhouse-backups"
  #  schedule: "0 3 * * *"
  #  cleanupStrategy: "--keep-last=5 --keep-daily=7 --keep-within-weekly=2m"
  #  s3AccessKey: "your-s3-access-key"
  #  s3SecretKey: "your-s3-secret-key"
  #  resticPassword: "your-restic-password"

Using the kubeconfig provided by Hikube and this example yaml, saved as a manifest.yaml file, you can easily test the application deployment using the following command:

kubectl apply -f manifest.yaml

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Configurable Parameters

General Parameters

Name	Description	Default Value
size	Persistent volume size for data.	10Gi
logStorageSize	Persistent volume size for logs.	2Gi
shards	Number of ClickHouse shards.	1
replicas	Number of ClickHouse replicas in each shard.	2
storageClass	Storage class used for data and logs.	"replicated" or "local"
logTTL	Retention time for query_log and query_thread_log, expressed in days.	15

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Configuration Parameters

Name	Description	Default Value
users	ClickHouse users configuration. Each user can have custom permissions.	{}

Example:

users:
  user1:
    password: strongpassword
  user2:
    readonly: true
    password: hackme

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Backup Parameters

Name	Description	Default Value
backup.enabled	Enables or disables periodic backups.	false
backup.s3Region	AWS S3 region where backups are stored.	us-east-1
backup.s3Bucket	S3 bucket name used for backups.	s3.example.org/clickhouse-backups
backup.schedule	Backup schedule (Cron format).	0 2 * * *
backup.cleanupStrategy	Cleanup strategy for old backups.	--keep-last=3 --keep-daily=3 --keep-within-weekly=1m
backup.s3AccessKey	AWS S3 access key for authentication.	oobaiRus9pah8PhohL1ThaeTa4UVa7gu
backup.s3SecretKey	AWS S3 secret key for authentication.	ju3eum4dekeich9ahM1te8waeGai0oog
backup.resticPassword	Password for Restic backup encryption.	ChaXoveekoh6eigh4siesheeda2quai0

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Restoring a Backup

You can restore a ClickHouse backup using Restic. Here are the main steps:

Finding a Snapshot

Use the following command to list available snapshots in your S3 bucket:

restic -r s3:s3.tenant.hikube.cloud/clickhouse-backups/table_name snapshots

Restoring the Snapshot

To restore the most recent snapshot, run the following command specifying a restoration target:

restic -r s3:s3.tenant.hikube.cloud/clickhouse-backups/table_name restore latest --target /tmp/

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Additional Resources

To learn more about ClickHouse and its management, check the following resources:

• Official ClickHouse Documentation Comprehensive guide for configuring and optimizing ClickHouse.
• Restic Documentation Guide for configuring and using Restic for backups.