Configure cluster parameters

The KubeBlocks configuration function provides a set of consistent default configuration generation strategies for all the databases running on KubeBlocks and also provides a unified parameter configuration interface to facilitate managing parameter configuration, searching the parameter user guide, and validating parameter effectiveness.

From v0.6.0, KubeBlocks supports kbcli cluster configure and kbcli cluster edit-config to configure parameters. The difference is that KubeBlocks configures parameters automatically with kbcli cluster configure but kbcli cluster edit-config provides a visualized way for you to edit parameters directly.

View parameter information

View the current configuration file of a cluster.

kbcli cluster describe-config mykafka  

From the meta information, the cluster mykafka has a configuration file named server.properties.

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

• View the details of the current configuration file.

  kbcli cluster describe-config mykafka --show-detail

• View the parameter description.

  kbcli cluster explain-config mykafka | head -n 20

• View the user guide of a specified parameter.

  kbcli cluster explain-config mykafka --param=log.cleanup.policy
  Output

  template meta:
    ConfigSpec: kafka-configuration-tpl   ComponentName: broker   ClusterName: mykafka
  
  Configure Constraint:
    Parameter Name:     log.cleanup.policy
    Allowed Values:     "compact","delete"
    Scope:              Global
    Dynamic:            false
    Type:               string
    Description:        The default cleanup policy for segments beyond the retention window. A comma separated list of valid policies. 
  • 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. Currently, Kafka only supports static strategy, i.e. Dynamic is false. Restarting is required to make the configuration effective.
  • Description: It describes the parameter definition.

Configure parameters

Configure parameters with configure command

1. View the current value of log.cleanup.policy.

   kbcli cluster describe-config mykafka --show-detail | grep log.cleanup.policy
   >
   log.cleanup.policy=delete

2. Adjust the value of log.cleanup.policy.

   kbcli cluster configure mykafka --set=log.cleanup.policy=compact
   note

   Make sure the value you set is within the Allowed Values of this parameter. Otherwise, the configuration may fail.

3. View the status of the parameter configuration.

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

   When the Status.Status shows Succeed, the configuration is completed.

   Output

   # In progress
   kbcli cluster describe-ops mykafka-reconfiguring-wvqns -n default
   >
   Spec:
     Name: mykafka-reconfiguring-wvqns NameSpace: default  Cluster: mykafka    Type: Reconfiguring
   
   Command:
     kbcli cluster configure mykafka --components=broker --config-spec=kafka-configuration-tpl --config-file=server.properties --set log.cleanup.policy=compact --namespace=default
   
   Status:
     Start Time:         Sep 14,2023 16:28 UTC+0800
     Duration:           5s
     Status:             Running
     Progress:           0/1
                         OBJECT-KEY   STATUS   DURATION   MESSAGE

   # Parameter reconfiguration is completed
   kbcli cluster describe-ops mykafka-reconfiguring-wvqns -n default
   >
   Spec:
     Name: mykafka-reconfiguring-wvqns NameSpace: default  Cluster: mykafka    Type: Reconfiguring
   
   Command:
     kbcli cluster configure mykafka --components=broker --config-spec=kafka-configuration-tpl --config-file=server.properties --set log.cleanup.policy=compact --namespace=default
   
   Status:
     Start Time:         Sep 14,2023 16:28 UTC+0800
     Completion Time:    Sep 14,2023 16:28 UTC+0800
     Duration:           25s
     Status:             Succeed
     Progress:           1/1
                         OBJECT-KEY   STATUS   DURATION   MESSAGE

4. View the configuration file to verify whether the parameter is configured as expected.

   The whole searching process has a 30-second delay.

   kbcli cluster describe-config mykafka --show-detail | grep log.cleanup.policy
   >
   log.cleanup.policy = compact
   mykafka-reconfiguring-wvqns   mykafka   broker      kafka-configuration-tpl   server.properties   Succeed   restart   1/1        Sep 14,2023 16:28 UTC+0800   {"server.properties":"{\"log.cleanup.policy\":\"compact\"}"}

Configure parameters with edit-config command

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

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

1. Edit the configuration file.

   kbcli cluster edit-config mykafka
   note

   If there are multiple components in a cluster, use --component 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 mykafka
   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 mykafka                 

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 mykafka-reconfiguring-wvqns mykafka-reconfiguring-hxqfx
>
DIFF-CONFIG RESULT:
  ConfigFile: server.properties TemplateName: kafka-configuration-tpl   ComponentName: broker   ClusterName: mykafka    UpdateType: update

PARAMETERNAME         MYKAFKA-RECONFIGURING-WVQNS   MYKAFKA-RECONFIGURING-HXQFX
log.retention.hours   168                           200