Upgrading the Minor Kernel Version of a DB Instance

Scenarios

You can upgrade the minor kernel version of your DB instance to improve performance, optimize functions, and fix bugs.

For details about the minor kernel versions, see TaurusDB Kernel Version Release History.

Upgrade Methods

A minor kernel version can be upgraded in either of the following ways:

Upon submission: The system upgrades the minor kernel version upon your manual submission of the upgrade request.
In maintenance window: The system upgrades the minor kernel version during the maintenance window you have specified. For details about how to change the maintenance window, see Changing the Maintenance Window of a DB Instance.

If the kernel version of your DB instance has potential risks or major defects, has expired, or has been brought offline, the system will notify you by SMS message or email and deliver an upgrade task during the maintenance window.

Precautions

When any new minor kernel version is released for addressing issues and vulnerabilities from the open source community, upgrade the minor kernel version of your DB instance immediately or during the maintenance window.
An upgrade will reboot your DB instance and interrupt services intermittently. To minimize the impact of the upgrade, perform the upgrade during off-peak hours, or ensure that your applications support automatic reconnection.
If a DB instance contains a large number of table partitions (more than 1 million), it may take more than 2 hours to reboot the instance.
If you want to upgrade the minor kernel version of your DB instance from 8.0.18 to 8.0.22 and there are more than 1,000 partitions, the upgrade may fail. Contact Huawei Cloud engineers to check the version compatibility before the upgrade.
If the primary node and read replicas of a DB instance are deployed in the same AZ, a minor kernel version upgrade will trigger a failover. If they are in different AZs, a minor kernel version upgrade will trigger two failovers. A failover means that the system fails over to a read replica in case the primary node is unavailable.
When you upgrade a minor kernel version of a DB instance, minor versions of read replicas (if any) will also be upgraded automatically. Minor versions of read replicas cannot be upgraded separately. A minor kernel version upgrade cannot be rolled back after the upgrade is complete.
DDL operations on events, such as CREATE EVENT, DROP EVENT, and ALTER EVENT, are not allowed during a minor kernel version upgrade.
If the replication delay between the primary node and read replicas is longer than 300 seconds, the minor kernel version cannot be upgraded.
If the kernel version is earlier than 2.0.51.240305, it will be upgraded to 2.0.51.240305 first.
To upgrade the kernel version to 2.0.54.240600 or later, ensure that rds_global_sql_log_bin is ON and binlog_expire_logs_seconds is greater than or equal to 86400. For details about parameter settings, see Modifying Parameters of a DB Instance.

Upgrading the Minor Kernel Version of a Single DB Instance

Log in to the management console.
Click in the upper left corner and select a region and project.
Click in the upper left corner of the page and choose Databases > TaurusDB.
On the Instances page, click the instance name to go to the Basic Information page.
In the Instance Information area, click Upgrade under Kernel Version.

Figure 1 Upgrading the minor kernel version on the Basic Information page

Alternatively, go to the Instances page and click Upgrade in the DB Engine Version column.

Figure 2 Upgrading the minor kernel version on the Instances page
In the displayed dialog box, set Scheduled Time and click OK.

Figure 3 TaurusDB minor version pre-upgrade
- Upon submission: The system upgrades the minor kernel version immediately after your submission of the upgrade request. In the Task Center page, click Instant Tasks and view the task progress.
- In maintenance window: The system upgrades the minor kernel version during the maintenance window you have specified. After the operation is complete, on the Task Center page, click Scheduled Tasks and view the information about the upgrade task.
The first upgrade is a pre-upgrade, during which the instance will not be rebooted and your workloads will not be affected.
The system will automatically conduct a pre-upgrade check.

In the displayed dialog box, read the message carefully and click OK to proceed with the kernel upgrade.
Figure 4 Pre-upgrade check
After the pre-upgrade is complete, the instance status becomes Pre-upgrade completed, which means no other operations are allowed. On the Basic Information page, click Upgrade under Kernel Version again.

Figure 5 Upgrading the kernel version

In the displayed dialog box, click OK. Wait until the kernel version upgrade is complete.

Figure 6 Minor version upgrade
- A data dictionary upgrade will cause the TaurusDB instance to reboot and briefly interrupt workloads for about 30 to 90 seconds. To minimize the impact of the upgrade, perform the upgrade during off-peak hours, or ensure that your applications support automatic reconnection.
- A database dictionary upgrade involves changes to the underlying data dictionary and may take a long time.
- Binlog needs to be enabled for data dictionary upgrades. Ensure that the value of rds_global_sql_log_bin is ON and the value of binlog_expire_logs_seconds is at least 86400.
- The first upgrade is a pre-upgrade, during which the instance will not be rebooted and your workloads will not be affected.
- After the pre-upgrade is complete, the instance status becomes Pre-upgrade completed, which means no other operations are allowed. Go to the Basic Information page and click Upgrade under Kernel Version again. The second upgrade will cause the instance to reboot, so workloads will be interrupted. The upgrade takes 15 to 20 minutes, and workloads are intermittently interrupted for 1 to 2 minutes. To minimize the impacts, perform the upgrade during off-peak hours.
- After the upgrade is complete, the instance status becomes Kernel version upgrade to be confirmed, which means no other operations are allowed. To make the instance available again, go to the Basic Information page and click Apply Upgrade under Kernel Version.
- If the upgrade fails, the instance will be rolled back to a previous version and its data will be restored to a new instance with the name original_instance_name_copy. The original instance will become unavailable after the rollback, and the new instance will start to incur charges once the original instance is deleted.
- Data cannot be restored to a point in time when a data dictionary upgrade was in progress. By default, the system searches forward for the most recent available point in time instead.
- During the period between a data dictionary upgrade and the next full backup, data of the instance cannot be restored to the original instance or an existing instance.
- When restoring backups, ensure that the data dictionary version of the target instance is the same as that of the source instance.

Upgrading Minor Kernel Versions of Multiple DB Instances at a Time

On the Instances page, select the desired DB instances and click Upgrade in the upper left corner of the list.

Figure 7 Upgrading minor kernel versions of multiple DB instances at a time

A maximum of 100 DB instances can be selected at a time.
In the displayed dialog box, confirm the information about the DB instances to be upgraded and set Scheduled Time.

Figure 8 Selecting a scheduled time
- Upon submission: The system upgrades the minor kernel version immediately after your submission of the upgrade request. In the Task Center page, click Instant Tasks and view the task progress.
- In maintenance window: The system upgrades the minor kernel version during the maintenance window you have specified. After the operation is complete, on the Task Center page, click Scheduled Tasks and view the information about the upgrade task.
Confirm the information, enter YES in the text box as prompted, and click OK.
- Wait for 2 to 5 minutes and check whether the upgrade has been started for the DB instance. If the upgrade has not been started, check whether the value of rds_global_sql_log_bin is ON and the value of binlog_expire_logs_seconds is at least 86400. If the parameters are not correctly configured, the upgrade cannot be performed.
- If the parameters are correctly configured but the upgrade has not started, it could be due to that the value of rds_sql_log_bin_inconsistent_count is not 0. Wait until this value becomes 0 before proceeding with the upgrade.

Follow-up Operations

Return to the instance list. In the navigation pane, choose Task Center and check the progress of the upgrade task.

If you have selected Upon submission for Scheduled Time:
On the Instant Tasks page, search for "Upgrading a DB instance version" and check the execution progress. Instant tasks cannot be canceled.
If you have selected In maintenance window for Scheduled Time:
On the Scheduled Tasks page, search for the instance ID and check the execution status of the upgrade task.

If the task is in the To be executed state, you can click Cancel to cancel the task.