New to KubeDB? Please start here.
This guide will show you how to use KubeDB Ops-manager operator to reconfigure a Redis database.
Before You Begin
At first, you need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster.
Install KubeDB Provisioner and Ops-manager operator in your cluster following the steps here.
You should be familiar with the following KubeDB concepts:
To keep everything isolated, we are going to use a separate namespace called demo throughout this tutorial.
$ kubectl create ns demo
namespace/demo created
Note: YAML files used in this tutorial are stored in docs/examples/redis directory of kubedb/docs repository.
Now, we are going to deploy a Redis database using a supported version by KubeDB operator. Then we are going to apply RedisOpsRequest to reconfigure its configuration.
Prepare Redis Database
Now, we are going to deploy a Redis database with version 6.2.14.
Deploy Redis
At first, we will create redis.conf file containing required configuration settings.
$ cat redis.conf
maxclients 500
Here, maxclients is set to 500, whereas the default value is 10000.
Now, we will create a secret with this configuration file.
$ kubectl create secret generic -n demo rd-custom-config --from-file=./redis.conf
secret/rd-custom-config created
In this section, we are going to create a Redis object specifying spec.configSecret field to apply this custom configuration. Below is the YAML of the Redis CR that we are going to create,
apiVersion: kubedb.com/v1alpha2
kind: Redis
metadata:
name: sample-redis
namespace: demo
spec:
version: "6.2.14"
storageType: Durable
storage:
storageClassName: "standard"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
configSecret:
name: rd-custom-config
Let’s create the Redis CR we have shown above,
$ kubectl create -f https://github.com/kubedb/docs/raw/v2024.3.16/docs/examples/redis/reconfigure/sample-redis-config.yaml
redis.kubedb.com/sample-redis created
Now, wait until sample-redis has status Ready. i.e,
$ kubectl get rd -n demo
NAME VERSION STATUS AGE
sample-redis 6.2.14 Ready 23s
Now, we will check if the database has started with the custom configuration we have provided.
First we need to get the username and password to connect to a redis instance,
$ kubectl get secrets -n demo sample-redis-auth -o jsonpath='{.data.\username}' | base64 -d
default
$ kubectl get secrets -n demo sample-redis-auth -o jsonpath='{.data.\password}' | base64 -d
0PI1tYTyzp;YaXOh
Now let’s connect to a redis instance and run a redis internal command to check the configuration we have provided.
$ kubectl exec -n demo sample-redis-0 -- redis-cli config get maxclients
maxclients
500
As we can see from the configuration of running redis, the value of maxclients has been set to 500.
Now we will reconfigure this database to set maxclients to 2000.
Now, we will edit the redis.conf file containing required configuration settings.
$ cat redis.conf
maxclients 2000
Then, we will create a new secret with this configuration file.
$ kubectl create secret generic -n demo new-custom-config --from-file=./redis.conf
secret/new-custom-config created
Create RedisOpsRequest
Now, we will use this secret to replace the previous secret using a RedisOpsRequest CR. The RedisOpsRequest yaml is given below,
apiVersion: ops.kubedb.com/v1alpha1
kind: RedisOpsRequest
metadata:
name: rdops-reconfigure
namespace: demo
spec:
type: Reconfigure
databaseRef:
name: sample-redis
configuration:
configSecret:
name: new-custom-config
Here,
spec.databaseRef.name specifies that we are reconfiguring sample-redis database.spec.type specifies that we are performing Reconfigure on our database.spec.configuration.configSecret.name specifies the name of the new secret.
Let’s create the RedisOpsRequest CR we have shown above,
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.3.16/docs/examples/redis/reconfigure/rdops-reconfigure.yaml
redisopsrequest.ops.kubedb.com/rdops-reconfigure created
Verify the new configuration is working
If everything goes well, KubeDB Ops-manager operator will update the configSecret of Redis object.
Let’s wait for RedisOpsRequest to be Successful. Run the following command to watch RedisOpsRequest CR,
$ watch kubectl get redisopsrequest -n demo
Every 2.0s: kubectl get redisopsrequest -n demo
NAME TYPE STATUS AGE
rdops-reconfigure Reconfigure Successful 1m
We can see from the above output that the RedisOpsRequest has succeeded. If we describe the RedisOpsRequest we will get an overview of the steps that were followed to reconfigure the database.
$ kubectl describe redisopsrequest -n demo rdops-reconfigure
Name: rdops-reconfigure
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: ops.kubedb.com/v1alpha1
Kind: RedisOpsRequest
Metadata:
Creation Timestamp: 2024-02-02T09:33:08Z
Generation: 1
Resource Version: 2702
UID: a0ec9260-65cf-4001-b905-e0e4d0530cc9
Spec:
Apply: IfReady
Configuration:
Config Secret:
Name: new-custom-config
Database Ref:
Name: sample-redis
Type: Reconfigure
Status:
Conditions:
Last Transition Time: 2024-02-02T09:33:08Z
Message: Redis ops request is reconfiguring the cluster
Observed Generation: 1
Reason: Reconfigure
Status: True
Type: Reconfigure
Last Transition Time: 2024-02-02T09:33:11Z
Message: reconfiguring new secret
Observed Generation: 1
Reason: patchedSecret
Status: True
Type: patchedSecret
Last Transition Time: 2024-02-02T09:33:11Z
Message: reconfiguring redis
Observed Generation: 1
Reason: UpdateStatefulSets
Status: True
Type: UpdateStatefulSets
Last Transition Time: 2024-02-02T09:33:21Z
Message: Restarted pods after reconfiguration
Observed Generation: 1
Reason: RestartPods
Status: True
Type: RestartPods
Last Transition Time: 2024-02-02T09:33:21Z
Message: Successfully completed the modification process.
Observed Generation: 1
Reason: Successful
Status: True
Type: Successful
Observed Generation: 1
Phase: Successful
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal PauseDatabase 101s KubeDB Ops-manager Operator Pausing Redis demo/sample-redis
Normal RestartPods 88s KubeDB Ops-manager Operator Restarted pods after reconfiguration
Normal ResumeDatabase 88s KubeDB Ops-manager Operator Resuming Redis demo/sample-redis
Normal ResumeDatabase 88s KubeDB Ops-manager Operator Successfully resumed Redis demo/sample-redis
Normal Successful 88s KubeDB Ops-manager Operator Successfully Reconfigured Database
Now let’s connect to a redis instance and run a redis internal command to check the new configuration we have provided.
$ kubectl exec -n demo sample-redis-0 -- redis-cli config get maxclients
maxclients
2000
As we can see from the configuration of running redis, the value of maxclients has been changed from 500 to 20000. So the reconfiguration of the database is successful.
Now we will reconfigure this database again to set maxclients to 3000. This time we won’t use a new secret. We will use the inlineConfig field of the RedisOpsRequest. This will merge the new config in the existing secret.
Create RedisOpsRequest
Now, we will use the new configuration in the data field in the RedisOpsRequest CR. The RedisOpsRequest yaml is given below,
apiVersion: ops.kubedb.com/v1alpha1
kind: RedisOpsRequest
metadata:
name: rdops-inline-reconfig
namespace: demo
spec:
type: Reconfigure
databaseRef:
name: sample-redis
configuration:
inlineConfig: maxclients 3000
Here,
spec.databaseRef.name specifies that we are reconfiguring sample-redis database.spec.type specifies that we are performing Reconfigure on our database.spec.configuration.inlineConfig specifies the new configuration that will be merged in the existing secret.
Let’s create the RedisOpsRequest CR we have shown above,
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.3.16/docs/examples/redis/reconfigure/rdops-inline-reconfig.yaml
redisopsrequest.ops.kubedb.com/rdops-inline-reconfig created
Verify the new configuration is working
If everything goes well, KubeDB Ops-manager operator will merge this new config with the existing configuration.
Let’s wait for RedisOpsRequest to be Successful. Run the following command to watch RedisOpsRequest CR,
$ watch kubectl get redisopsrequest -n demo
Every 2.0s: kubectl get redisopsrequest -n demo
NAME TYPE STATUS AGE
rdops-inline-reconfig Reconfigure Successful 38s
We can see from the above output that the RedisOpsRequest has succeeded. If we describe the RedisOpsRequest we will get an overview of the steps that were followed to reconfigure the database.
$ kubectl describe redisopsrequest -n demo rdops-inline-reconfig
Name: rdops-inline-reconfig
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: ops.kubedb.com/v1alpha1
Kind: RedisOpsRequest
Metadata:
Creation Timestamp: 2024-02-02T09:42:33Z
Generation: 1
Resource Version: 3550
UID: fceacc94-df88-42a1-8991-f77056f33a75
Spec:
Apply: IfReady
Configuration:
Inline Config: maxclients 3000
Database Ref:
Name: sample-redis
Type: Reconfigure
Status:
Conditions:
Last Transition Time: 2024-02-02T09:42:33Z
Message: Redis ops request is reconfiguring the cluster
Observed Generation: 1
Reason: Reconfigure
Status: True
Type: Reconfigure
Last Transition Time: 2024-02-02T09:42:36Z
Message: reconfiguring new secret
Observed Generation: 1
Reason: patchedSecret
Status: True
Type: patchedSecret
Last Transition Time: 2024-02-02T09:42:36Z
Message: reconfiguring redis
Observed Generation: 1
Reason: UpdateStatefulSets
Status: True
Type: UpdateStatefulSets
Last Transition Time: 2024-02-02T09:42:46Z
Message: Restarted pods after reconfiguration
Observed Generation: 1
Reason: RestartPods
Status: True
Type: RestartPods
Last Transition Time: 2024-02-02T09:42:46Z
Message: Successfully completed the modification process.
Observed Generation: 1
Reason: Successful
Status: True
Type: Successful
Observed Generation: 1
Phase: Successful
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal PauseDatabase 27s KubeDB Ops-manager Operator Pausing Redis demo/sample-redis
Normal RestartPods 14s KubeDB Ops-manager Operator Restarted pods after reconfiguration
Normal ResumeDatabase 14s KubeDB Ops-manager Operator Resuming Redis demo/sample-redis
Normal ResumeDatabase 14s KubeDB Ops-manager Operator Successfully resumed Redis demo/sample-redis
Normal Successful 14s KubeDB Ops-manager Operator Successfully Reconfigured Database
Now let’s connect to a redis instance and run a redis internal command to check the new configuration we have provided.
$ kubectl exec -n demo sample-redis-0 -- redis-cli config get maxclients
maxclients
3000
As we can see from the configuration of running redis, the value of maxclients has been changed from 2000 to 3000. So the reconfiguration of the database using the inlineConfig field is successful.
Cleaning Up
To clean up the Kubernetes resources created by this tutorial, run:
kubectl delete rd -n demo sample-redis
kubectl delete redisopsrequest -n demo rdops-reconfigure rdops-inline-reconfig
