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PerconaXtraDB QuickStart
This tutorial will show you how to use KubeDB to run a PerconaXtraDB database.
Note: The yaml files used in this tutorial are stored in here.
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. If you do not already have a cluster, you can create one by using kind.
Now, install KubeDB cli on your workstation and KubeDB operator in your cluster following the steps here.
StorageClass is required to run KubeDB. Check the available StorageClass in cluster.
$ kubectl get storageclasses
NAME PROVISIONER RECLAIMPOLICY VOLUMEBINDINGMODE ALLOWVOLUMEEXPANSION AGE
standard (default) rancher.io/local-path Delete WaitForFirstConsumer false 6h22m
- To keep things isolated, this tutorial uses a separate namespace called
demothroughout this tutorial.
$ kubectl create ns demo
namespace/demo created
Find Available PerconaXtraDBVersion
When you have installed KubeDB, it has created PerconaXtraDBVersion crd for all supported PerconaXtraDB versions. Check it by using the following command,
$ kubectl get perconaxtradbversions
NAME VERSION DB_IMAGE DEPRECATED AGE
8.0.26 8.0.26 percona/percona-xtradb-cluster:8.0.26 6m1s
8.0.28 8.0.28 percona/percona-xtradb-cluster:8.0.28 6m1s
Create a PerconaXtraDB database
KubeDB implements a PerconaXtraDB CRD to define the specification of a PerconaXtraDB database. Below is the PerconaXtraDB object created in this tutorial.
apiVersion: kubedb.com/v1alpha2
kind: PerconaXtraDB
metadata:
name: sample-pxc
namespace: demo
spec:
version: "8.0.26"
storageType: Durable
storage:
storageClassName: "standard"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
terminationPolicy: Delete
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2023.01.17/docs/guides/percona-xtradb/quickstart/overview/examples/sample-pxc.yaml
perconaxtradb.kubedb.com/sample-pxc created
Here,
spec.versionis the name of the PerconaXtraDBVersion CRD where the docker images are specified. In this tutorial, a PerconaXtraDB8.0.26database is going to create.spec.storageTypespecifies the type of storage that will be used for PerconaXtraDB database. It can beDurableorEphemeral. Default value of this field isDurable. IfEphemeralis used then KubeDB will create PerconaXtraDB database usingEmptyDirvolume. In this case, you don’t have to specifyspec.storagefield. This is useful for testing purposes.spec.storagespecifies the StorageClass of PVC dynamically allocated to store data for this database. This storage spec will be passed to the StatefulSet created by KubeDB operator to run database pods. You can specify any StorageClass available in your cluster with appropriate resource requests.spec.terminationPolicygives flexibility whether tonullify(reject) the delete operation ofPerconaXtraDBcrd or which resources KubeDB should keep or delete when you deletePerconaXtraDBcrd. If admission webhook is enabled, It prevents users from deleting the database as long as thespec.terminationPolicyis set toDoNotTerminate.
Note:
spec.storagesection is used to create PVC for database pod. It will create PVC with storage size specified instorage.resources.requestsfield. Don’t specify limits here. PVC does not get resized automatically.
KubeDB operator watches for PerconaXtraDB objects using Kubernetes api. When a PerconaXtraDB object is created, KubeDB operator will create a new StatefulSet and a Service with the matching PerconaXtraDB object name. KubeDB operator will also create a governing service for StatefulSets with the name kubedb, if one is not already present.
$ kubectl describe -n demo perconaxtradb sample-pxc
Name: sample-pxc
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: kubedb.com/v1alpha2
Kind: PerconaXtraDB
Metadata:
Creation Timestamp: 2022-12-19T09:54:09Z
Finalizers:
kubedb.com
Generation: 4
...
Resource Version: 4309
UID: 75511bbb-d24f-41a9-9b1c-4bfffd1f5289
Spec:
Allowed Schemas:
Namespaces:
From: Same
Auth Secret:
Name: sample-pxc-auth
Auto Ops:
Coordinator:
Resources:
Health Checker:
Failure Threshold: 1
Period Seconds: 10
Timeout Seconds: 10
Pod Template:
Controller:
Metadata:
Spec:
Affinity:
Pod Anti Affinity:
Preferred During Scheduling Ignored During Execution:
Pod Affinity Term:
Label Selector:
Match Labels:
app.kubernetes.io/instance: sample-pxc
app.kubernetes.io/managed-by: kubedb.com
app.kubernetes.io/name: perconaxtradbs.kubedb.com
Namespaces:
demo
Topology Key: kubernetes.io/hostname
Weight: 100
Pod Affinity Term:
Label Selector:
Match Labels:
app.kubernetes.io/instance: sample-pxc
app.kubernetes.io/managed-by: kubedb.com
app.kubernetes.io/name: perconaxtradbs.kubedb.com
Namespaces:
demo
Topology Key: failure-domain.beta.kubernetes.io/zone
Weight: 50
Resources:
Limits:
Memory: 1Gi
Requests:
Cpu: 500m
Memory: 1Gi
Security Context:
Fs Group: 1001
Run As Group: 1001
Run As User: 1001
Service Account Name: sample-pxc
Replicas: 3
Storage:
Access Modes:
ReadWriteOnce
Resources:
Requests:
Storage: 1Gi
Storage Class Name: standard
Storage Type: Durable
System User Secrets:
Monitor User Secret:
Name: sample-pxc-monitor
Replication User Secret:
Name: sample-pxc-replication
Termination Policy: Delete
Version: 8.0.26
Status:
Conditions:
Last Transition Time: 2022-12-19T09:54:09Z
Message: The KubeDB operator has started the provisioning of PerconaXtraDB: demo/sample-pxc
Reason: DatabaseProvisioningStartedSuccessfully
Status: True
Type: ProvisioningStarted
Last Transition Time: 2022-12-19T09:56:53Z
Message: All desired replicas are ready.
Reason: AllReplicasReady
Status: True
Type: ReplicaReady
Last Transition Time: 2022-12-19T10:00:03Z
Message: database sample-pxc/demo is ready
Observed Generation: 4
Reason: ReadinessCheckSucceeded
Status: True
Type: Ready
Last Transition Time: 2022-12-19T09:59:13Z
Message: database sample-pxc/demo is accepting connection
Observed Generation: 4
Reason: AcceptingConnection
Status: True
Type: AcceptingConnection
Last Transition Time: 2022-12-19T10:00:19Z
Message: The PerconaXtraDB: demo/sample-pxc is successfully provisioned.
Observed Generation: 4
Reason: DatabaseSuccessfullyProvisioned
Status: True
Type: Provisioned
Observed Generation: 4
Phase: Ready
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal PhaseChanged 6m42s KubeDB Operator Phase changed from to Provisioning.
Normal Successful 6m42s KubeDB Operator Successfully created governing service
Normal Successful 6m42s KubeDB Operator Successfully created Service
Normal Successful 6m32s KubeDB Operator Successfully created StatefulSet demo/sample-pxc
Normal Successful 6m32s KubeDB Operator Successfully created PerconaXtraDB
Normal Successful 6m32s KubeDB Operator Successfully created appbinding
Normal PhaseChanged 51s KubeDB Operator Phase changed from NotReady to Provisioning.
Normal PhaseChanged 32s KubeDB Operator Phase changed from Provisioning to Ready.
$ kubectl get statefulset -n demo
NAME READY AGE
sample-pxc 1/1 27m
$ kubectl get pvc -n demo
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
data-sample-pxc-0 Bound pvc-10651900-d975-467f-80ff-9c4755bdf917 1Gi RWO standard 27m
$ kubectl get pv -n demo
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
pvc-10651900-d975-467f-80ff-9c4755bdf917 1Gi RWO Delete Bound demo/data-sample-pxc-0 standard 27m
$ kubectl get service -n demo
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
sample-pxc ClusterIP 10.105.207.172 <none> 3306/TCP 28m
sample-pxc-pods ClusterIP None <none> 3306/TCP 28m
KubeDB operator sets the status.phase to Running once the database is successfully created. Run the following command to see PerconaXtraDB object status:
$ kubectl get perconaxtradb -n demo
NAME VERSION STATUS AGE
sample-pxc 8.0.26 Ready 9m32s
Connect with PerconaXtraDB database
KubeDB operator has created a new Secret called sample-pxc-auth for storing the password for perconaxtradb superuser. This secret contains a username key which contains the username for PerconaXtraDB superuser and a password key which contains the password for PerconaXtraDB superuser.
If you want to use an existing secret please specify that when creating the PerconaXtraDB object using spec.authSecret.name. While creating this secret manually, make sure the secret contains these two keys containing data username and password and also make sure of using root as value of username.
Now, we need username and password to connect to this database from kubeclt exec command. In this example, sample-pxc-auth secret holds username and password.
$ kubectl get secrets -n demo sample-pxc-auth -o jsonpath='{.data.\username}' | base64 -d
root
$ kubectl get secrets -n demo sample-pxc-auth -o jsonpath='{.data.\password}' | base64 -d
w*yOU$b53dTbjsjJ
We will exec into the pod sample-pxc-0 and connet to the database using username and password.
$ kubectl exec -it -n demo sample-pxc-0 -- perconaxtradb -u root --password='w*yOU$b53dTbjsjJ'
Server version: 8.0.26-16.1 Percona XtraDB Cluster (GPL), Release rel16, Revision b141904, WSREP version 26.4.3
Copyright (c) 2009-2021 Percona LLC and/or its affiliates
Copyright (c) 2000, 2021, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| kubedb_system |
| mysql |
| performance_schema |
| sys |
+--------------------+
5 rows in set (0.00 sec)
Database TerminationPolicy
This field is used to regulate the deletion process of the related resources when PerconaXtraDB object is deleted. User can set the value of this field according to their needs. The available options and their use case scenario is described below:
DoNotTerminate:
When terminationPolicy is set to DoNotTerminate, KubeDB takes advantage of ValidationWebhook feature in Kubernetes 1.9.0 or later clusters to implement DoNotTerminate feature. If admission webhook is enabled, It prevents users from deleting the database as long as the spec.terminationPolicy is set to DoNotTerminate. If you create a database with terminationPolicy DoNotTerminate and try to delete it, you will see this:
$ kubectl delete perconaxtradb sample-pxc -n demo
Error from server (BadRequest): admission webhook "perconaxtradb.validators.kubedb.com" denied the request: perconaxtradb "perconaxtradb-quickstart" can't be halted. To delete, change spec.terminationPolicy
Now, run kubectl edit perconaxtradb sample-pxc -n demo to set spec.terminationPolicy to Halt (which deletes the perconaxtradb object and keeps PVC, snapshots, Secrets intact) or remove this field (which default to Delete). Then you will be able to delete/halt the database.
Halt:
Suppose you want to reuse your database volume and credential to deploy your database in future using the same configurations. But, right now you just want to delete the database except the database volumes and credentials. In this scenario, you must set the PerconaXtraDB object terminationPolicy to Halt.
When the TerminationPolicy is set to Halt and the PerconaXtraDB object is deleted, the KubeDB operator will delete the StatefulSet and its pods but leaves the PVCs, secrets and database backup data(snapshots) intact. You can set the terminationPolicy to Halt in existing database using edit command for testing.
At first, run kubectl edit perconaxtradb sample-pxc -n demo to set spec.terminationPolicy to Halt. Then delete the perconaxtradb object,
$ kubectl delete perconaxtradb sample-pxc -n demo
perconaxtradb.kubedb.com "sample-pxc" deleted
Now, run the following command to get all perconaxtradb resources in demo namespaces,
$ kubectl get sts,svc,secret,pvc -n demo
NAME TYPE DATA AGE
secret/default-token-w2pgw kubernetes.io/service-account-token 3 31m
secret/sample-pxc-auth kubernetes.io/basic-auth 2 39s
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
persistentvolumeclaim/data-sample-pxc-0 Bound pvc-7502c222-2b02-4363-9027-91ab0e7b76dc 1Gi RWO standard 39s
From the above output, you can see that all perconaxtradb resources(StatefulSet, Service, etc.) are deleted except PVC and Secret. You can recreate your perconaxtradb again using this resources.
Delete:
If you want to delete the existing database along with the volumes used, but want to restore the database from previously taken snapshots and secrets then you might want to set the PerconaXtraDB object terminationPolicy to Delete. In this setting, StatefulSet and the volumes will be deleted. If you decide to restore the database, you can do so using the snapshots and the credentials.
When the TerminationPolicy is set to Delete and the PerconaXtraDB object is deleted, the KubeDB operator will delete the StatefulSet and its pods along with PVCs but leaves the secret and database backup data(snapshots) intact.
Suppose, we have a database with terminationPolicy set to Delete. Now, are going to delete the database using the following command:
$ kubectl delete perconaxtradb sample-pxc -n demo
perconaxtradb.kubedb.com "sample-pxc" deleted
Now, run the following command to get all perconaxtradb resources in demo namespaces,
$ kubectl get sts,svc,secret,pvc -n demo
NAME READY AGE
statefulset.apps/sample-pxc 3/3 3m46s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/sample-pxc ClusterIP 10.96.128.19 <none> 3306/TCP 4m5s
service/sample-pxc-pods ClusterIP None <none> 3306/TCP 4m5s
NAME TYPE DATA AGE
secret/default-token-r556j kubernetes.io/service-account-token 3 20m
secret/sample-pxc-auth kubernetes.io/basic-auth 2 20m
secret/sample-pxc-monitor kubernetes.io/basic-auth 2 20m
secret/sample-pxc-replication kubernetes.io/basic-auth 2 20m
secret/sample-pxc-token-p25ww kubernetes.io/service-account-token 3 4m5s
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
persistentvolumeclaim/data-sample-pxc-0 Bound pvc-11f7b634-689e-457e-ba41-157a51090475 1Gi RWO standard 3m46s
persistentvolumeclaim/data-sample-pxc-1 Bound pvc-84dce4b5-35df-4a06-bfea-b0530d83ebb0 1Gi RWO standard 3m46s
persistentvolumeclaim/data-sample-pxc-2 Bound pvc-85a35a7c-dfb8-4ca2-96a6-21c9e0b892db 1Gi RWO standard 3m46s
From the above output, you can see that all perconaxtradb resources(StatefulSet, Service, PVCs etc.) are deleted except Secret.
If you don’t set the terminationPolicy then the kubeDB set the TerminationPolicy to Delete by-default.
WipeOut:
You can totally delete the PerconaXtraDB database and relevant resources without any tracking by setting terminationPolicy to WipeOut. KubeDB operator will delete all relevant resources of this PerconaXtraDB database (i.e, PVCs, Secrets, Snapshots) when the terminationPolicy is set to WipeOut.
Suppose, we have a database with terminationPolicy set to WipeOut. Now, are going to delete the database using the following command:
$ kubectl delete perconaxtradb sample-pxc -n demo
perconaxtradb.kubedb.com "sample-pxc" deleted
Now, run the following command to get all perconaxtradb resources in demo namespaces,
$ kubectl get sts,svc,secret,pvc -n demo
No resources found in demo namespace.
From the above output, you can see that all perconaxtradb resources are deleted. there is no option to recreate/reinitialize your database if terminationPolicy is set to Delete.
Be careful when you set the
terminationPolicytoDelete. Because there is no option to trace the database resources if once deleted the database.
Database Halted
If you want to delete PerconaXtraDB resources(StatefulSet,Service, etc.) without deleting the PerconaXtraDB object, PVCs and Secret you have to set the spec.halted to true. KubeDB operator will be able to delete the PerconaXtraDB related resources except the PerconaXtraDB object, PVCs and Secret.
Suppose we have a database running perconaxtradb-quickstart in our cluster. Now, we are going to set spec.halted to true in PerconaXtraDB object by running kubectl edit -n demo perconaxtradb-quickstart command.
Run the following command to get PerconaXtraDB resources,
$ kubectl get perconaxtradb,sts,secret,svc,pvc -n demo
NAME VERSION STATUS AGE
perconaxtradb.kubedb.com/sample-pxc 8.0.26 Halted 22m
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/sample-pxc ClusterIP 10.96.128.19 <none> 3306/TCP 4m5s
service/sample-pxc-pods ClusterIP None <none> 3306/TCP 4m5s
NAME TYPE DATA AGE
secret/default-token-r556j kubernetes.io/service-account-token 3 20m
secret/sample-pxc-auth kubernetes.io/basic-auth 2 20m
secret/sample-pxc-monitor kubernetes.io/basic-auth 2 20m
secret/sample-pxc-replication kubernetes.io/basic-auth 2 20m
secret/sample-pxc-token-p25ww kubernetes.io/service-account-token 3 4m5s
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
persistentvolumeclaim/data-sample-pxc-0 Bound pvc-11f7b634-689e-457e-ba41-157a51090475 1Gi RWO standard 3m46s
persistentvolumeclaim/data-sample-pxc-1 Bound pvc-84dce4b5-35df-4a06-bfea-b0530d83ebb0 1Gi RWO standard 3m46s
persistentvolumeclaim/data-sample-pxc-2 Bound pvc-85a35a7c-dfb8-4ca2-96a6-21c9e0b892db 1Gi RWO standard 3m46s
From the above output , you can see that PerconaXtraDB object, PVCs, Secret are still alive. Then you can recreate your PerconaXtraDB with same configuration.
When you set
spec.haltedtotrueinPerconaXtraDBobject then theterminationPolicyis also set toHaltby KubeDB operator.
Cleaning up
To cleanup the Kubernetes resources created by this tutorial, run:
kubectl delete -n demo perconaxtradb/sample-pxc
kubectl delete ns demo
Tips for Testing
If you are just testing some basic functionalities, you might want to avoid additional hassles due to some safety features that are great for production environment. You can follow these tips to avoid them.
- Use
storageType: Ephemeral. Databases are precious. You might not want to lose your data in your production environment if database pod fail. So, we recommend to usespec.storageType: Durableand provide storage spec inspec.storagesection. For testing purpose, you can just usespec.storageType: Ephemeral. KubeDB will use emptyDir for storage. You will not require to providespec.storagesection. - Use
terminationPolicy: WipeOut. It is nice to be able to delete everything created by KubeDB for a particular PerconaXtraDB crd when you delete the crd.
Next Steps
- Want to hack on KubeDB? Check our contribution guidelines.