TiDB Latest Development Version Upgrade Guide

This document is targeted for users who want to upgrade from TiDB 2.0, 2.1, 3.0, or 3.1 versions to the latest development version (latest), or from an earlier development version to the latest development version. The latest development version is compatible with TiDB Binlog of the cluster version.

Warning:

The latest development version of TiDB is not a stable version. Do not use it in the production environment.

Upgrade caveat

  • Rolling back to 2.1.x or earlier versions after upgrading is not supported.

  • Before upgrading to latest from 2.0.6 or earlier versions, check if there are any running DDL operations, especially time-consuming ones like Add Index. If there are any, wait for the DDL operations to finish before you upgrade.

  • Parallel DDL is supported in TiDB 2.1 and later versions. Therefore, for clusters with a TiDB version earlier than 2.0.1, rolling update to latest is not supported. To upgrade, you can choose either of the following two options:

    • Stop the cluster and upgrade to latest directly.
    • Roll update to 2.0.1 or later 2.0.x versions, and then roll update to the latest version.

Note:

Do not execute any DDL statements during the upgrading process, otherwise the undefined behavior error might occur.

Step 1: Install Ansible and dependencies on the Control Machine

Note:

If you have installed Ansible and its dependencies, you can skip this step.

The latest development version of TiDB Ansible depends on Ansible 2.4.2 ~ 2.7.11 (2.4.2 ≦ ansible ≦ 2.7.11, Ansible 2.7.11 recommended) and the Python modules of jinja2 ≧ 2.9.6 and jmespath ≧ 0.9.0.

To make it easy to manage dependencies, use pip to install Ansible and its dependencies. For details, see Install Ansible and its dependencies on the Control Machine. For offline environment, see Install Ansible and its dependencies offline on the Control Machine.

After the installation is finished, you can view the version information using the following command:

ansible --version
ansible 2.7.11
pip show jinja2
Name: Jinja2
Version: 2.10
pip show jmespath
Name: jmespath
Version: 0.9.0

Note:

  • You must install Ansible and its dependencies following the above procedures.
  • Make sure that the Jinja2 version is correct, otherwise an error occurs when you start Grafana.
  • Make sure that the jmespath version is correct, otherwise an error occurs when you perform a rolling update to TiKV.

Step 2: Download TiDB Ansible to the Control Machine

  1. Log in to the Control Machine using the tidb user account and enter the /home/tidb directory.

  2. Back up the tidb-ansible folders of TiDB 2.0, 2.1, 3.0, or an earlier latest version using the following command:

    mv tidb-ansible tidb-ansible-bak
    
  3. Download the tidb-ansible with the tag corresponding to the latest version of TiDB. For more details, See Download TiDB-Ansible to the Control Machine. The default folder name is tidb-ansible.

    git clone https://github.com/pingcap/tidb-ansible.git
    

Step 3: Edit the inventory.ini file and the configuration file

Log in to the Control Machine using the tidb user account and enter the /home/tidb/tidb-ansible directory.

Edit the inventory.ini file

Edit the inventory.ini file. For IP information, see the /home/tidb/tidb-ansible-bak/inventory.ini backup file.

Note:

Pay special attention to the following variables configuration. For variable meaning, see Description of other variables.

  1. Make sure that ansible_user is the normal user. For unified privilege management, remote installation using the root user is no longer supported. The default configuration uses the tidb user as the SSH remote user and the program running user.

    ## Connection
    # ssh via normal user
    ansible_user = tidb
    

    You can refer to How to configure SSH mutual trust and sudo rules on the Control Machine to automatically configure the mutual trust among hosts.

  2. Keep the process_supervision variable consistent with that in the previous version. It is recommended to use systemd by default.

    # process supervision, [systemd, supervise]
    process_supervision = systemd
    

    If you need to modify this variable, see How to modify the supervision method of a process from supervise to systemd. Before you upgrade, first use the /home/tidb/tidb-ansible-bak/ backup branch to modify the supervision method of a process.

Edit the configuration file of TiDB cluster components

If you have previously customized the configuration file of TiDB cluster components, refer to the backup file to modify the corresponding configuration file in the /home/tidb/tidb-ansible/conf directory.

Note the following parameter changes:

  • In the TiKV configuration, end-point-concurrency is changed to three parameters: high-concurrency, normal-concurrency and low-concurrency.

    readpool:
      coprocessor:
        # Notice: if CPU_NUM > 8, default thread pool size for coprocessors
        # will be set to CPU_NUM * 0.8.
        # high-concurrency: 8
        # normal-concurrency: 8
        # low-concurrency: 8
    

    Note:

    For the cluster topology of multiple TiKV instances (processes) on a single machine, you need to modify the three parameters above.

    Recommended configuration: the number of TiKV instances * the parameter value = the number of CPU cores * 0.8.

  • In the TiKV configuration, the block-cache-size parameter of different CFs is changed to block-cache.

    storage:
      block-cache:
        capacity: "1GB"
    

    Note:

    For the cluster topology of multiple TiKV instances (processes) on a single machine, you need to modify the capacity parameter.

    Recommended configuration: capacity = MEM_TOTAL * 0.5 / the number of TiKV instances.

  • In the TiKV configuration, you need to configure the tikv_status_port port for the multiple instances on a single machine scenario. Before you configure it, check whether a port conflict exists.

    [tikv_servers]
    TiKV1-1 ansible_host=172.16.10.4 deploy_dir=/data1/deploy tikv_port=20171 tikv_status_port=20181 labels="host=tikv1"
    TiKV1-2 ansible_host=172.16.10.4 deploy_dir=/data2/deploy tikv_port=20172 tikv_status_port=20182 labels="host=tikv1"
    TiKV2-1 ansible_host=172.16.10.5 deploy_dir=/data1/deploy tikv_port=20171 tikv_status_port=20181 labels="host=tikv2"
    TiKV2-2 ansible_host=172.16.10.5 deploy_dir=/data2/deploy tikv_port=20172 tikv_status_port=20182 labels="host=tikv2"
    TiKV3-1 ansible_host=172.16.10.6 deploy_dir=/data1/deploy tikv_port=20171 tikv_status_port=20181 labels="host=tikv3"
    TiKV3-2 ansible_host=172.16.10.6 deploy_dir=/data2/deploy tikv_port=20172 tikv_status_port=20182 labels="host=tikv3"
    

Step 4: Download TiDB latest binary to the Control Machine

Make sure that tidb_version = latest in the tidb-ansible/inventory.ini file, and then run the following command to download TiDB latest binary to the Control Machine:

ansible-playbook local_prepare.yml

Step 5: Perform a rolling update to TiDB cluster components

  • If the process_supervision variable uses the default systemd parameter, perform a rolling update to the TiDB cluster using the following command corresponding to your current TiDB cluster version.

    • When the TiDB cluster version < 3.0.0, use excessive_rolling_update.yml.

      ansible-playbook excessive_rolling_update.yml
      
    • When the TiDB cluster version ≧ 3.0.0, use rolling_update.yml for both rolling updates and daily rolling restarts.

      ansible-playbook rolling_update.yml
      
  • If the process_supervision variable uses the supervise parameter, perform a rolling update to the TiDB cluster using rolling_update.yml, no matter what version the current TiDB cluster is.

    ansible-playbook rolling_update.yml
    

Step 6: Perform a rolling update to TiDB monitoring components

ansible-playbook rolling_update_monitor.yml