Manage versions in Managed ClickHouse®

Managed ClickHouse® supports multiple ClickHouse versions. You can choose a version when you create a service and upgrade to a newer supported version later.

Supported ClickHouse versions

Managed ClickHouse supports the following major versions:

• 25.3: default for services created before May 5, 2026
• 25.8: default for services created on or after May 5, 2026

List the versions the platform currently offers, along with the default one:

exo dbaas type show clickhouse

If you don’t specify a version when you create a service, Exoscale uses the default version in effect on the creation date. To pick a version explicitly, set the version field in the JSON body passed to exo x create-dbaas-service-clickhouse:

echo '{"plan":"startup-16","version":"25.3","ip-filter":["<your-ip>/32"]}' | \
  exo x create-dbaas-service-clickhouse my-clickhouse -z ch-gva-2

Exoscale doesn’t automatically upgrade existing 25.3 services to 25.8. To upgrade the ClickHouse version of an existing service, see Upgrade your service.

For supported versions and end-of-life timelines, see the Managed ClickHouse® version support policy.

Before you upgrade

Before upgrading your service, complete the following checks:

• Review the upstream ClickHouse release notes.
• Test the upgrade in a development or staging environment by forking the service and upgrading the fork first.
• Verify that your applications and clients support the target version.
• Ensure recent backups are available.
• Avoid running long-running queries or heavy ingestion during the upgrade.

Downgrading to an earlier ClickHouse version is not supported.

How upgrades work

During an upgrade, the platform replaces service nodes with new nodes running the selected version.

• New service nodes are created with the selected ClickHouse version.
• The new nodes start alongside the existing nodes.
• Data is streamed from the existing nodes to the new nodes.
• After the migration completes, the service switches to the upgraded nodes.
• The previous nodes are removed.

This process avoids modifying the existing nodes directly during the upgrade.

During this process:

• Queries connected to nodes being replaced can fail and require retries.
• New connections are routed to upgraded nodes.

Service availability during upgrades

The service remains available during the upgrade.

• New nodes are added and receive data before old nodes are removed, which helps keep the service reachable while the upgrade runs.
• Short interruptions can occur.
• Latency can increase and throughput can decrease during the upgrade.

Upgrade your service

Upgrade the service to a newer supported ClickHouse version with the Exoscale CLI.

1. Check the available ClickHouse versions:

   exo dbaas type show clickhouse

2. Upgrade the service:

   echo '{"version":"CLICKHOUSE_VERSION"}' | \
     exo x update-dbaas-service-clickhouse SERVICE_NAME -z ZONE

   Parameters:

   • SERVICE_NAME: Name of the service
   • ZONE: Exoscale zone of the service, for example ch-gva-2
   • CLICKHOUSE_VERSION: Target ClickHouse version, for example 25.8

   The service stays reachable during the upgrade.