This document is targeted for users who want to upgrade from TiKV 4.0 versions to TiKV 5.0 versions, or from TiKV 5.0 to a later version.

Preparations

This section introduces the preparation works needed before upgrading your TiKV cluster, including upgrading TiUP and the TiUP Cluster component.

Step 1: Upgrade TiUP

Before upgrading your TiKV cluster, you first need to upgrade TiUP.

1. Upgrade the TiUP version. It is recommended that the TiUP version is 1.4.0 or later.

   tiup update --self
   tiup --version

2. Upgrade the TiUP Cluster version. It is recommended that the TiUP Cluster version is 1.4.0 or later.

   tiup update cluster
   tiup cluster --version

Step 2: Edit TiUP topology configuration file

Skip this step if one of the following situations applies:

• You have not modified the configuration parameters of the original cluster. Or you have modified the configuration parameters using tiup cluster but no more modification is needed.
• After the upgrade, you want to use v5.0’s default parameter values for the unmodified configuration items.

1. Edit the topology file:

   tiup cluster edit-config <cluster-name>

2. Refer to the format of topology configuration template and fill the parameters you want to modify in the server_configs section of the topology file.

3. Save the changes and exit the editing mode.

Perform a rolling upgrade to the TiKV cluster

This section describes how to perform a rolling upgrade to the TiKV cluster and how to verify the version after the upgrade.

Upgrade the TiKV cluster to a specified version

You can upgrade your cluster in one of the two ways: online upgrade and offline upgrade.

By default, TiUP Cluster upgrades the TiKV cluster using the online method, which means that the TiKV cluster can still provide services during the upgrade process. With the online method, the leaders are migrated one by one on each node before the upgrade and restart. Therefore, for a large-scale cluster, it takes a long time to complete the entire upgrade operation.

If your application has a maintenance window for the database to be stopped for maintenance, you can use the offline upgrade method to quickly perform the upgrade operation.

Online upgrade

tiup cluster upgrade <cluster-name> <version>

For example, if you want to upgrade the cluster to v5.0.1:

tiup cluster upgrade <cluster-name> v5.0.1

• Performing a rolling upgrade to the cluster will upgrade all components one by one. During the upgrade of TiKV, all leaders in a TiKV instance are evicted before stopping the instance. The default timeout time is 5 minutes (300 seconds). The instance is directly stopped after this timeout time.

• To perform the upgrade immediately without evicting the leader, specify --force in the command above. This method causes performance jitter but not data loss.

• To keep a stable performance, make sure that all leaders in a TiKV instance are evicted before stopping the instance. You can set --transfer-timeout to a larger value, for example, --transfer-timeout 3600 (unit: second).

Offline upgrade

1. Before the offline upgrade, you first need to stop the entire cluster.

   tiup cluster stop <cluster-name>

2. Use the upgrade command with the --offline option to perform the offline upgrade.

   tiup cluster upgrade <cluster-name> <version> --offline

3. After the upgrade, the cluster will not be automatically restarted. You need to use the start command to restart it.

   tiup cluster start <cluster-name>

Verify the cluster version

Execute the display command to view the latest cluster version TiKV Version:

tiup cluster display <cluster-name>
Cluster name:       <cluster-name>
Cluster version:    v5.0.1

FAQ

This section describes common problems encountered when updating the TiKV cluster using TiUP.

If an error occurs and the upgrade is interrupted, how to resume the upgrade after fixing this error?

Re-execute the tiup cluster upgrade command to resume the upgrade. The upgrade operation restarts the nodes that have been previously upgraded. If you do not want the upgraded nodes to be restarted, use the replay sub-command to retry the operation:

1. Execute tiup cluster audit to see the operation records:

   tiup cluster audit

   Find the failed upgrade operation record and keep the ID of this operation record. The ID is the <audit-id> value in the next step.

2. Execute tiup cluster replay <audit-id> to retry the corresponding operation:

   tiup cluster replay <audit-id>

The evict leader has waited too long during the upgrade. How to skip this step for a quick upgrade?

You can specify --force. Then the processes of transferring PD leader and evicting TiKV leader are skipped during the upgrade. The cluster is directly restarted to update the version, which has a great impact on the cluster that runs online. Here is the command:

tiup cluster upgrade <cluster-name> <version> --force

How to update the version of tools such as pd-ctl after upgrading the TiKV cluster?

You can upgrade the tool version by using TiUP to install the ctl component of the corresponding version:

tiup install ctl:v5.0.0