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This guide walks you through the process of getting started with the KubeBlocks MySQL Add-on, including prerequisites, enabling the add-on, creating a MySQL cluster, and managing the cluster with ease.
This tutorial assumes that you have a Kubernetes cluster installed and running, and that you have installed the kubectl command line tool and helm somewhere in your path. Please see the getting started and Installing Helm for installation instructions for your platform.
Also, this example requires KubeBlocks installed and running. Please see the Install KubeBlocks to install KubeBlocks.
Verify whether MySQL Addon is installed. By default, the MySQL Addon is installed along with the KubeBlocks Helm chart.
helm list -A
NAME NAMESPACE REVISION UPDATED STATUS CHART APP VERSION
...
kb-addon-mysql kb-system 1 2024-12-16 00:28:52.78819557 +0000 UTC deployed mysql-1.0.0 5.7.44
If MySQL Addon is not enabled, you can enable it by following the steps below.
# Add Helm repo
helm repo add kubeblocks-addons https://apecloud.github.io/helm-charts
# For users in Mainland China, if github is not accessible or very slow for you, please use following repo instead
#helm repo add kubeblocks-addons https://jihulab.com/api/v4/projects/150246/packages/helm/stable
# Update helm repo
helm repo update
# Search versions of the Addon
helm search repo kubeblocks/mysql --versions
# Install the version you want (replace $version with the one you need)
helm upgrade -i mysql kubeblocks-addons/mysql --version $version -n kb-system
kubectl apply -f https://raw.githubusercontent.com/apecloud/kubeblocks-addons/refs/heads/main/examples/mysql/cluster.yaml
apiVersion: apps.kubeblocks.io/v1
kind: Cluster
metadata:
name: mysql-cluster
namespace: demo
spec:
# Specifies the behavior when a Cluster is deleted.
# Valid options are: [DoNotTerminate, Delete, WipeOut] (`Halt` is deprecated since KB 0.9)
# - `DoNotTerminate`: Prevents deletion of the Cluster. This policy ensures that all resources remain intact.
# - `Delete`: Extends the `Halt` policy by also removing PVCs, leading to a thorough cleanup while removing all persistent data.
# - `WipeOut`: An aggressive policy that deletes all Cluster resources, including volume snapshots and backups in external storage. This results in complete data removal and should be used cautiously, primarily in non-production environments to avoid irreversible data loss.
terminationPolicy: Delete
# Specifies a list of ClusterComponentSpec objects used to define the
# individual Components that make up a Cluster.
# This field allows for detailed configuration of each Component within the Cluster
componentSpecs:
- name: mysql
# Specifies the ComponentDefinition custom resource (CR) that defines the
# Component's characteristics and behavior.
# Supports three different ways to specify the ComponentDefinition:
# - the regular expression - recommended
# - the full name - recommended
# - the name prefix
componentDef: "mysql-8.0" # match all CMPD named with 'mysql-8.0-'
# ServiceVersion specifies the version of the Service expected to be
# provisioned by this Component.
# When componentDef is "mysql-8.0",
# Valid options are: [8.0.30,8.0.31,8.0.32,8.0.33,8.0.34,8.0.35,8.0.36,8.0.37,8.0.38,8.0.39]
serviceVersion: 8.0.35
# Determines whether metrics exporter information is annotated on the
# Component's headless Service.
# Valid options are [true, false]
disableExporter: false
# Specifies the desired number of replicas in the Component
replicas: 2
# Specifies the resources required by the Component.
resources:
limits:
cpu: '0.5'
memory: 0.5Gi
requests:
cpu: '0.5'
memory: 0.5Gi
# Specifies a list of PersistentVolumeClaim templates that define the storage
# requirements for the Component.
volumeClaimTemplates:
# Refers to the name of a volumeMount defined in
# `componentDefinition.spec.runtime.containers[*].volumeMounts
- name: data
spec:
# The name of the StorageClass required by the claim.
# If not specified, the StorageClass annotated with
# `storageclass.kubernetes.io/is-default-class=true` will be used by default
storageClassName: ""
accessModes:
- ReadWriteOnce
resources:
requests:
# Set the storage size as needed
storage: 20Gi
If you want to create a cluster of specified version, set spec.componentSpecs.componentDef (major version) and spec.componentSpecs.serviceVersion (major and minor version) field in the yaml file before applying it, for examples:
componentSpecs:
- name: mysql
# componentDef is "mysql-5.7" means the major version is 5.7
componentDef: "mysql-5.7"
# Valid options are: [5.7.44]
serviceVersion: 5.7.44
componentSpecs:
- name: mysql
# componentDef is "mysql-8.0" means the major version is 8.0
componentDef: "mysql-8.0"
# Valid options are: [8.0.30,8.0.31,8.0.32,8.0.33,8.0.34,8.0.35,8.0.36,8.0.37,8.0.38,8.0.39]
serviceVersion: 8.0.35
componentSpecs:
- name: mysql
# componentDef is "mysql-8.4" means the major version is 8.4
componentDef: "mysql-8.4"
# Valid options are: [8.4.0, 8.4.1, 8.4.2]
serviceVersion: 8.4.2
The list of available componentDef can be found by following command:
kubectl get cmpd -l app.kubernetes.io/name=mysql
The list of supported versions can be found by following command:
kubectl get cmpv mysql
When you create a MySQL cluster, KubeBlocks automatically creates a MySQL cluster that includes one primary replica and one secondary replica. The primary and secondary replicas are synchronized using semi-synchronous replication.
When the cluster's status.phase changes to Running, it indicates that the cluster has been successfully created, and both the primary and secondary replicas have been started.
kubectl get cluster mysql-cluster
NAME CLUSTER-DEFINITION TERMINATION-POLICY STATUS AGE
mysql-cluster Delete Running 22m
kubectl get pods -l app.kubernetes.io/instance=mysql-cluster
NAME READY STATUS RESTARTS AGE
mysql-cluster-mysql-0 4/4 Running 0 31m
mysql-cluster-mysql-1 4/4 Running 0 31m
If you have installed kbcli, you can use the kbcli tool to quickly view important information related to the cluster.
kbcli cluster describe mysql-cluster
Name: mysql-cluster Created Time: Dec 16,2024 08:37 UTC+0800
NAMESPACE CLUSTER-DEFINITION VERSION STATUS TERMINATION-POLICY
default Running Delete
Endpoints:
COMPONENT MODE INTERNAL EXTERNAL
mysql ReadWrite mysql-cluster-mysql.default.svc.cluster.local:3306 <none>
Topology:
COMPONENT INSTANCE ROLE STATUS AZ NODE CREATED-TIME
mysql mysql-cluster-mysql-0 secondary Running ap-southeast-1b ip-10-0-2-243.ap-southeast-1.compute.internal/10.0.2.243 Dec 16,2024 08:37 UTC+0800
mysql mysql-cluster-mysql-1 primary Running ap-southeast-1a ip-10-0-1-215.ap-southeast-1.compute.internal/10.0.1.215 Dec 16,2024 08:37 UTC+0800
Resources Allocation:
COMPONENT DEDICATED CPU(REQUEST/LIMIT) MEMORY(REQUEST/LIMIT) STORAGE-SIZE STORAGE-CLASS
mysql false 500m / 500m 512Mi / 512Mi data:20Gi <none>
Images:
COMPONENT TYPE IMAGE
mysql docker.io/apecloud/mysql:8.0.35
Data Protection:
BACKUP-REPO AUTO-BACKUP BACKUP-SCHEDULE BACKUP-METHOD BACKUP-RETENTION RECOVERABLE-TIME
Show cluster events: kbcli cluster list-events -n default mysql-cluster
When creating a MySQL Cluster, KubeBlocks creates a Secret named "mysql-cluster-mysql-account-root" to store the MySQL root username and password.
kubectl get secret -l app.kubernetes.io/instance=mysql-cluster
NAME TYPE DATA AGE
mysql-cluster-mysql-account-kbadmin Opaque 2 61s
mysql-cluster-mysql-account-kbdataprotection Opaque 2 61s
mysql-cluster-mysql-account-kbmonitoring Opaque 2 61s
mysql-cluster-mysql-account-kbprobe Opaque 2 61s
mysql-cluster-mysql-account-kbreplicator Opaque 2 61s
mysql-cluster-mysql-account-proxysql Opaque 2 61s
mysql-cluster-mysql-account-root Opaque 2 61s
You can obtain the MySQL root username and password from secret 'mysql-cluster-mysql-account-root' using the following two commands:
kubectl get secret mysql-cluster-mysql-account-root -o jsonpath='{.data.username}' | base64 --decode
kubectl get secret mysql-cluster-mysql-account-root -o jsonpath='{.data.password}' | base64 --decode
KubeBlocks by default creates a Service of type ClusterIP named "mysql-cluster-mysql" to access the MySQL Cluster.
kubectl get svc -l app.kubernetes.io/instance=mysql-cluster
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
mysql-cluster-mysql ClusterIP 172.20.253.119 <none> 3306/TCP 153m
You can log in to a Pod within the Kubernetes cluster, such as the primary replica of the MySQL Cluster, and access the database through this Service. Within the same Kubernetes cluster, the ClusterIP is accessible.
kubectl exec -ti -n default mysql-cluster-mysql-0 -- mysql -h mysql-cluster-mysql -uroot -pkni676X2W1
Alternatively, you can use the kubectl port-forward command to map port 3306 of the primary replica of the MySQL Cluster to port 3306 on your local machine:
kubectl port-forward svc/mysql-cluster-mysql 3306:3306 -n default
Forwarding from 127.0.0.1:3306 -> 3306
Forwarding from [::1]:3306 -> 3306
Then, open another shell and use the mysql command-line tool to connect to the local port 3306:
mysql -h 127.0.0.1 -P3306 -uroot -pkni676X2W1
Using kubectl exec and kubectl port-forward are methods intended for quickly testing the operator's functionality and should not be used in production environments. In production, you should use a Service to access the MySQL Cluster. If accessing the database from outside Kubernetes, a LoadBalancer or NodePort type Service that provides an EXTERNAL-IP is required. Refer to Accessing MySQL Cluster to configure the Service in your environment.
Stop the cluster will release all the Pods of the cluster, but the PVC, Secret, ConfigMap and Service resources will be retained. It is useful when you want to save the cost of the cluster.
kubectl apply -f https://raw.githubusercontent.com/apecloud/kubeblocks-addons/refs/heads/main/examples/mysql/stop.yaml
apiVersion: operations.kubeblocks.io/v1alpha1
kind: OpsRequest
metadata:
name: mysql-stop
namespace: demo
spec:
# Specifies the name of the Cluster resource that this operation is targeting.
clusterName: mysql-cluster
type: Stop
Alternatively, you may stop the cluster by setting the spec.componentSpecs.stop field to true.
kubectl edit cluster mysql-cluster
spec:
componentSpecs:
- name: mysql
stop: true # set stop `true` to stop the component
replicas: 2
Start the stopped cluster
kubectl apply -f https://raw.githubusercontent.com/apecloud/kubeblocks-addons/refs/heads/main/examples/mysql/start.yaml
apiVersion: operations.kubeblocks.io/v1alpha1
kind: OpsRequest
metadata:
name: mysql-start
namespace: demo
spec:
# Specifies the name of the Cluster resource that this operation is targeting.
clusterName: mysql-cluster
type: Start
Alternatively, you may start the stopped cluster by setting the spec.componentSpecs.stop field to false.
kubectl edit cluster mysql-cluster
spec:
componentSpecs:
- name: mysql
stop: false # set to `false` (or remove this field) to start the component
replicas: 2
You can delete the Cluster using the following command:
kubectl delete cluster mysql-cluster
The behavior when deleting the Cluster depends on the value of the terminationPolicy field:
In a testing environment, you can delete the Cluster using the following command to release all resources.
kubectl patch cluster mysql-cluster -p '{"spec":{"terminationPolicy":"WipeOut"}}' --type="merge"
kubectl delete cluster mysql-cluster