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Configure cluster parameters

This guide shows how to configure cluster parameters.

From v0.9.0, KubeBlocks supports dynamic configuration. When the specification of a database instance changes (e.g. a user vertically scales a cluster), KubeBlocks automatically matches the appropriate configuration template based on the new specification. This is because different specifications of a database instance may require different optimal configurations to optimize performance and resource utilization. When you choose a different database instance specification, KubeBlocks automatically detects it and determines the best database configuration for the new specification, ensuring optimal performance and configuration of the database under the new specifications.

This feature simplifies the process of configuring parameters, which saves you from manually configuring database parameters as KubeBlocks handles the updates and configurations automatically to adapt to the new specifications. This saves time and effort and reduces performance issues caused by incorrect configuration.

But it's also important to note that the dynamic parameter configuration doesn't apply to all parameters. Some parameters may require manual configuration. Additionally, if you have manually modified database parameters before, KubeBlocks may overwrite your customized configurations when updating the database configuration template. Therefore, when using the dynamic configuration feature, it is recommended to back up and record your custom configuration so that you can restore them if needed.

View parameter information​

View the current configuration file of a cluster.

kbcli cluster describe-config mysql-cluster

From the meta information, the cluster mysql-cluster has a configuration file named my.cnf.

You can also view the details of this configuration file and parameters.

  • View the details of the current configuration file.

    kbcli cluster describe-config mysql-cluster --show-detail

  • View the parameter description.

    kbcli cluster explain-config mysql-cluster | head -n 20

  • View the user guide of a specified parameter.

    kbcli cluster explain-config mysql-cluster --param=innodb_buffer_pool_size --config-specs=mysql-consensusset-config

    --config-specs is required to specify a configuration template since ApeCloud MySQL currently supports multiple templates. You can run kbcli cluster describe-config mysql-cluster to view the all template names.

    Output
    template meta:
      ConfigSpec: mysql-consensusset-config        ComponentName: mysql        ClusterName: mysql-cluster

    Configure Constraint:
      Parameter Name:     innodb_buffer_pool_size
      Allowed Values:     [5242880-18446744073709552000]
      Scope:              Global
      Dynamic:            false
      Type:               integer
      Description:        The size in bytes of the memory buffer innodb uses to cache data and indexes of its tables
    • Allowed Values: It defines the valid value range of this parameter.
    • Dynamic: The value of Dynamic in Configure Constraint defines how the parameter configuration takes effect. There are two different configuration strategies based on the effectiveness type of modified parameters, i.e. dynamic and static.
      • When Dynamic is true, it means the effectiveness type of parameters is dynamic and can be configured online.
      • When Dynamic is false, it means the effectiveness type of parameters is static and a pod restarting is required to make the configuration effective.
    • Description: It describes the parameter definition.

Configure parameters​

Configure parameters with configure command​

The example below takes configuring max_connections and innodb_buffer_pool_size as an example.

  1. View the current values of max_connections and innodb_buffer_pool_size.

    kbcli cluster connect mysql-cluster
    mysql> show variables like '%max_connections%';
    >
    +-----------------+-------+
    | Variable_name   | Value |
    +-----------------+-------+
    | max_connections | 167   |
    +-----------------+-------+
    1 row in set (0.04 sec)
    mysql> show variables like '%innodb_buffer_pool_size%';
    >
    +-------------------------+-----------+
    | Variable_name           | Value     |
    +-------------------------+-----------+
    | innodb_buffer_pool_size | 134217728 |
    +-------------------------+-----------+
    1 row in set (0.00 sec)

  2. Adjust the values of max_connections and innodb_buffer_pool_size.

    kbcli cluster configure mysql-cluster --set=max_connections=600,innodb_buffer_pool_size=512M
    note

    Make sure the value you set is within the Allowed Values of this parameter. If you set a value that does not meet the value range, the system prompts an error. For example,

    kbcli cluster configure mysql-cluster  --set=max_connections=200,innodb_buffer_pool_size=2097152
    error: failed to validate updated config: [failed to cue template render configure: [mysqld.innodb_buffer_pool_size: invalid value 2097152 (out of bound >=5242880):
     343:34
    ]
    ]

  3. Search the status of the parameter configuration.

    Status.Progress shows the overall status of the parameter configuration and Conditions show the details.

    kbcli cluster describe-ops mysql-cluster-reconfiguring-z2wvn -n default
    Output
    Spec:
      Name: mysql-cluster-reconfiguring-z2wvn        NameSpace: default        Cluster: mysql-cluster        Type: Reconfiguring

     Command:
       kbcli cluster configure mysql-cluster --components=mysql --template-name=mysql-consensusset-config --config-file=my.cnf --set innodb_buffer_pool_size=512M --set max_connections=600

     Status:
       Start Time:         Mar 13,2023 02:55 UTC+0800
       Completion Time:    Mar 13,2023 02:55 UTC+0800
       Duration:           1s
       Status:             Succeed
       Progress:           1/1

     Conditions:
     LAST-TRANSITION-TIME         TYPE                 REASON                            STATUS   MESSAGE
     Mar 13,2023 02:55 UTC+0800   Progressing          OpsRequestProgressingStarted      True     Start to process the OpsRequest: mysql-cluster-reconfiguring-z2wvn in Cluster: mysql-cluster
     Mar 13,2023 02:55 UTC+0800   Validated            ValidateOpsRequestPassed          True     OpsRequest: mysql-cluster-reconfiguring-z2wvn is validated
     Mar 13,2023 02:55 UTC+0800   Reconfigure          ReconfigureStarted                True     Start to reconfigure in Cluster: mysql-cluster, Component: mysql
     Mar 13,2023 02:55 UTC+0800   ReconfigureMerged    ReconfigureMerged                 True     Reconfiguring in Cluster: mysql-cluster, Component: mysql, ConfigTpl: mysql-consensusset-config, info: updated: map[my.cnf:{"mysqld":{"innodb_buffer_pool_size":"512M","max_connections":"600"}}], added: map[], deleted:map[]
     Mar 13,2023 02:55 UTC+0800   ReconfigureSucceed   ReconfigureSucceed                True     Reconfiguring in Cluster: mysql-cluster, Component: mysql, ConfigTpl: mysql-consensusset-config, info: updated policy: <autoReload>, updated: map[my.cnf:{"mysqld":{"innodb_buffer_pool_size":"512M","max_connections":"600"}}], added: map[], deleted:map[]
     Mar 13,2023 02:55 UTC+0800   Succeed              OpsRequestProcessedSuccessfully   True     Successfully processed the OpsRequest: mysql-cluster-reconfiguring-z2wvn in Cluster: mysql-cluster

  4. Connect to the database to verify whether the parameters are configured as expected.

    The whole searching process has a 30-second delay since it takes some time for kubelet to synchronize modifications to the volume of the pod.

    kbcli cluster connect mysql-cluster
    mysql> show variables like '%max_connections%';
    >
    +-----------------+-------+
    | Variable_name   | Value |
    +-----------------+-------+
    | max_connections | 600   |
    +-----------------+-------+
    1 row in set (0.04 sec)
    mysql> show variables like '%innodb_buffer_pool_size%';
    >
    +-------------------------+-----------+
    | Variable_name           | Value     |
    +-------------------------+-----------+
    | innodb_buffer_pool_size | 536870912 |
    +-------------------------+-----------+
    1 row in set (0.00 sec)

Configure parameters with edit-config command​

For your convenience, KubeBlocks offers a tool edit-config to help you configure parameters in a visualized way.

For Linux and macOS, you can edit configuration files by vi. For Windows, you can edit files on the notepad.

The following steps take configuring MySQL Standalone as an example.

  1. Edit the configuration file.

    kbcli cluster edit-config mysql-cluster --config-specs=mysql-consensusset-config
    note
    • Since ApeCloud MySQL currently supports multiple templates, it is required to use --config-specs to specify a configuration template. You can run kbcli cluster describe-config mysql-cluster to view all template names.
    • If there are multiple components in a cluster, use --components to specify a component.

  2. View the status of the parameter configuration.

    kbcli cluster describe-ops xxx -n default

  3. Connect to the database to verify whether the parameters are configured as expected.

    kbcli cluster connect mysql-cluster
    note
    1. For the edit-config function, static parameters and dynamic parameters cannot be edited at the same time.
    2. Deleting a parameter will be supported later.

View history and compare differences​

After the configuration is completed, you can search the configuration history and compare the parameter differences.

View the parameter configuration history.

kbcli cluster describe-config mysql-cluster
>
ConfigSpecs Meta:
CONFIG-SPEC-NAME            FILE     ENABLED   TEMPLATE                   CONSTRAINT                    RENDERED                                  COMPONENT   CLUSTER                
mysql-consensusset-config   my.cnf   true      mysql8.0-config-template   mysql8.0-config-constraints   mysql-cluster-mysql-mysql-config   mysql       mysql-cluster   

History modifications:
OPS-NAME                            CLUSTER         COMPONENT   CONFIG-SPEC-NAME            FILE     STATUS    POLICY   PROGRESS   CREATED-TIME                 VALID-UPDATED                                                                                                                     
mysql-cluster-reconfiguring-4q5kv   mysql-cluster   mysql       mysql-consensusset-config   my.cnf   Succeed   reload   -/-        Mar 16,2023 15:44 UTC+0800   {"my.cnf":"{\"mysqld\":{\"max_connections\":\"3000\",\"read_buffer_size\":\"24288\"}}"}                                           
mysql-cluster-reconfiguring-cclvm   mysql-cluster   mysql       mysql-consensusset-config   my.cnf   Succeed   reload   -/-        Mar 16,2023 17:28 UTC+0800   {"my.cnf":"{\"mysqld\":{\"innodb_buffer_pool_size\":\"1G\",\"max_connections\":\"600\"}}"}   
mysql-cluster-reconfiguring-gx58r   mysql-cluster   mysql       mysql-consensusset-config   my.cnf   Succeed            -/-        Mar 16,2023 17:28 UTC+0800

From the above results, there are three parameter modifications.

Compare these modifications to view the configured parameters and their different values for different versions.

kbcli cluster diff-config mysql-cluster-reconfiguring-4q5kv mysql-cluster-reconfiguring-gx58r
>
DIFF-CONFIGURE RESULT:
  ConfigFile: my.cnf    TemplateName: mysql-consensusset-config ComponentName: mysql    ClusterName: mysql-cluster       UpdateType: update      

PARAMETERNAME             MYSQL-CLUSTER-RECONFIGURING-4Q5KV   MYSQL-CLUSTER-RECONFIGURING-GX58R   
max_connections           3000                                600                                        
innodb_buffer_pool_size   128M                                1G