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Run PerconaXtraDB with Custom PodTemplate
KubeDB supports providing custom configuration for PerconaXtraDB via PodTemplate. This tutorial will show you how to use KubeDB to run a PerconaXtraDB database with custom configuration using PodTemplate.
Before You Begin
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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.
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Now, install KubeDB cli on your workstation and KubeDB operator in your cluster following the steps here.
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To keep things isolated, this tutorial uses 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/mysql folder in GitHub repository kubedb/docs.
Overview
KubeDB allows providing a template for database pod through spec.podTemplate. KubeDB operator will pass the information provided in spec.podTemplate to the StatefulSet created for PerconaXtraDB database.
KubeDB accept following fields to set in spec.podTemplate:
- metadata:
- annotations (pod’s annotation)
- controller:
- annotations (statefulset’s annotation)
- spec:
- env
- resources
- initContainers
- imagePullSecrets
- nodeSelector
- affinity
- schedulerName
- tolerations
- priorityClassName
- priority
- securityContext
Read about the fields in details in PodTemplate concept,
CRD Configuration
Below is the YAML for the PerconaXtraDB created in this example. Here, spec.podTemplate.spec.env specifies environment variables and spec.podTemplate.spec.args provides extra arguments for PerconaXtraDB Docker Image.
In this tutorial, an initial database mdDB will be created by providing env MYSQL_DATABASE while the server character set will be set to utf8mb4 by adding extra args.
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
podTemplate:
spec:
env:
- name: MYSQL_DATABASE
value: mdDB
args:
- --character-set-server=utf8mb4
resources:
requests:
memory: "1Gi"
cpu: "250m"
terminationPolicy: WipeOut
$ kubectl create -f https://github.com/kubedb/docs/raw/v2023.01.17/docs/guides/percona-xtradb/configuration/using-pod-template/examples/md-misc-config.yaml
perconaxtradb.kubedb.com/sample-pxc created
Now, wait a few minutes. KubeDB operator will create necessary PVC, statefulset, services, secret etc. If everything goes well, we will see that a pod with the name sample-pxc has been created.
Check that the statefulset’s pod is running
$ kubectl get pod -n demo
NAME READY STATUS RESTARTS AGE
sample-pxc-0 2/2 Running 0 3m30s
sample-pxc-1 2/2 Running 0 3m30s
sample-pxc-2 2/2 Running 0 3m30s
Check the perconaxtradb CRD status if the database is ready
$ kubectl get perconaxtradb --all-namespaces
NAMESPACE NAME VERSION STATUS AGE
demo sample-pxc 8.0.26 Ready 4m8s
Once we see Note] mysqld: ready for connections. in the log, the database is ready.
Now, we will check if the database has started with the custom configuration we have provided.
$ kubectl exec -it -n demo sample-pxc-0 -- bash
Defaulted container "perconaxtradb" out of: perconaxtradb, px-coordinator, px-init (init)
bash-4.4$ mysql -u${MYSQL_ROOT_USERNAME} -p${MYSQL_ROOT_PASSWORD}
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 110
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 |
| mdDB |
| mysql |
| performance_schema |
| sys |
+--------------------+
6 rows in set (0.01 sec)
# Check character_set_server
mysql> show variables like 'char%';
+--------------------------+---------------------------------------------+
| Variable_name | Value |
+--------------------------+---------------------------------------------+
| character_set_client | latin1 |
| character_set_connection | latin1 |
| character_set_database | utf8mb4 |
| character_set_filesystem | binary |
| character_set_results | latin1 |
| character_set_server | utf8mb4 |
| character_set_system | utf8mb3 |
| character_sets_dir | /usr/share/percona-xtradb-cluster/charsets/ |
+--------------------------+---------------------------------------------+
8 rows in set (0.01 sec)
mysql> quit;
Bye
Cleaning up
To cleanup the Kubernetes resources created by this tutorial, run:
$ kubectl delete perconaxtradb -n demo sample-pxc
perconaxtradb.kubedb.com "sample-pxc" deleted
$ kubectl delete ns demo
namespace "demo" deleted
