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 redis-cluster --components=redis

From the meta information, the cluster redis-cluster has a configuration file named redis.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 redis-cluster --components=redis --show-detail

• View the parameter description.

  kbcli cluster explain-config redis-cluster --components=redis |head -n 20

• View the user guide of a specified parameter.

  kbcli cluster explain-config redis-cluster --components=redis --param=acllog-max-len
  Output

  template meta:
    ConfigSpec: redis-replication-config  ComponentName: redis    ClusterName: redis-cluster
  
  Configure Constraint:
    Parameter Name:     acllog-max-len
    Allowed Values:     [1-10000]
    Scope:              Global
    Dynamic:            true
    Type:               integer
    Description: 
  • 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 updated 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 configures acllog-max-len.

1. View the current values of acllog-max-len.

   kbcli cluster connect redis-cluster

   127.0.0.1:6379> config get parameter acllog-max-len
   1) "acllog-max-len"
   2) "128"

2. Adjust the values of acllog-max-len.

   kbcli cluster configure redis-cluster --components=redis --set=acllog-max-len=256
   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 redis-cluster  --set=acllog-max-len=1000000
   >
   error: failed to validate updated config: [failed to cue template render configure: [configuration."acllog-max-len": 2 errors in empty disjunction:
   configuration."acllog-max-len": conflicting values 128 and 1000000:
       20:43
       155:16
   configuration."acllog-max-len": invalid value 1000000 (out of bound <=10000):
       20:32
   ]
   ]

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.

   kbcli cluster describe-ops redis-cluster-reconfiguring-zjztm -n default
   Output

   Spec:
     Name: redis-cluster-reconfiguring-zjztm   NameSpace: default  Cluster: redis-cluster  Type: Reconfiguring
   
   Command:
     kbcli cluster configure redis-cluster --components=redis --config-spec=redis-replication-config --config-file=redis.conf --set acllog-max-len=256 --namespace=default
   
   Status:
     Start Time:         Apr 17,2023 17:22 UTC+0800
     Duration:           10s
     Status:             Running
     Progress:           0/1
                         OBJECT-KEY   STATUS   DURATION   MESSAGE
   
   Conditions:
   LAST-TRANSITION-TIME         TYPE                 REASON                         STATUS   MESSAGE
   Apr 17,2023 17:22 UTC+0800   Progressing          OpsRequestProgressingStarted   True     Start to process the OpsRequest: redis-cluster-reconfiguring-zjztm in Cluster: redis-cluster
   Apr 17,2023 17:22 UTC+0800   Validated            ValidateOpsRequestPassed       True     OpsRequest: redis-cluster-reconfiguring-zjztm is validated
   Apr 17,2023 17:22 UTC+0800   Reconfigure          ReconfigureStarted             True     Start to reconfigure in Cluster: redis-cluster, Component: redis
   Apr 17,2023 17:22 UTC+0800   ReconfigureRunning   ReconfigureRunning             True     Reconfiguring in Cluster: redis-cluster, Component: redis, ConfigSpec: redis-replication-config

4. Connect to the database to verify whether the parameter is 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 redis-cluster

   127.0.0.1:6379> config get parameter acllog-max-len
   1) "acllog-max-len"
   2) "256"

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.

1. Edit the configuration file.

   kbcli cluster edit-config redis-cluster
   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 redis-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 redis-cluster --components=redis

Output

ConfigSpecs Meta:
CONFIG-SPEC-NAME           FILE         ENABLED   TEMPLATE                 CONSTRAINT                  RENDERED                                       COMPONENT   CLUSTER
redis-replication-config   redis.conf   true      redis7-config-template   redis7-config-constraints   redis-cluster-redis-redis-replication-config   redis       redis-cluster

History modifications:
OPS-NAME                            CLUSTER         COMPONENT   CONFIG-SPEC-NAME           FILE         STATUS    POLICY    PROGRESS   CREATED-TIME                 VALID-UPDATED
redis-cluster-reconfiguring-zjztm   redis-cluster   redis       redis-replication-config   redis.conf   Succeed   restart   1/1        Apr 17,2023 17:22 UTC+0800
redis-cluster-reconfiguring-zrkq7   redis-cluster   redis       redis-replication-config   redis.conf   Succeed   restart   1/1        Apr 17,2023 17:28 UTC+0800   {"redis.conf":"{\"databases\":\"32\",\"maxclients\":\"20000\"}"}
redis-cluster-reconfiguring-mwbnw   redis-cluster   redis       redis-replication-config   redis.conf   Succeed   restart   1/1        Apr 17,2023 17:35 UTC+0800   {"redis.conf":"{\"maxclients\":\"40000\"}"}

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 redis-cluster-reconfiguring-zrkq7 redis-cluster-reconfiguring-mwbnw
>
DIFF-CONFIG RESULT:
  ConfigFile: redis.conf    TemplateName: redis-replication-config  ComponentName: redis    ClusterName: redis-cluster  UpdateType: update

PARAMETERNAME   REDIS-CLUSTER-RECONFIGURING-ZRKQ7   REDIS-CLUSTER-RECONFIGURING-MWBNW
maxclients      20000                               40000