Getting started with k8s: building MySQL with Helm

One 、 Series articles

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Chapter one ： k8s introduction ： Bare metal deployment k8s colony
Chapter two ： k8s introduction ： Deploy the application to k8s colony
The third chapter ： k8s introduction ：service Easy to use
Chapter four ： k8s introduction ：StatefulSet Easy to use
The fifth chapter ： k8s introduction ： Storage （storage）
Chapter six ： K8S To configure storageclass Use nfs Dynamically claim local disk space
Chapter vii. ： k8s introduction ： To configure ConfigMap & Secret
Chapter viii. ： k8s introduction ：k8s introduction ：Helm structure MySQL
Chapter nine ： k8s introduction ：kubernetes-dashboard install
Chapter ten ： k8s introduction ：kube-prometheus-stack The whole family can build （Grafana + Prometheus）

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Two 、 brief introduction

Helm similar npm,pip,docker hub, It can be understood as a software library , You can easily and quickly install some third-party software for our cluster .Helm Is to find 、 Share and use software to build Kubernetes The best way . Use Helm We can build it very conveniently MongoDB / MySQL Replica clusters ,YAML Others have written the documents for us , Use it directly

Helm Official website ：https://helm.sh/zh/docs/

Helm chart Warehouse Artifact Hub ：https://artifacthub.io/packages/search

Artifact Hub Is based on web Page application , Support CNCF Finding items 、 Install and release packages and configuration items , Including publicly released Helm chart. It is CNCF Sandbox project

Environmental Science ：

• linux：centos 7.9
• helm：v3.9.0
• docker：v20.10.17
• k8s：v1.23.1
• MySQL：v8.0.29
• MySQL chart：9.1.8

3、 ... and 、 Three concepts

• Chart： Represents the Helm package . It is contained in Kubernetes Running applications inside the cluster , All resource definitions required for a tool or service .

• Repository（ Warehouse ）： It's for storing and sharing charts The place of , for Kubernetes What the package uses .

• Release： Is running on the Kubernetes In the cluster chart Example . One chart It can usually be installed multiple times in the same cluster . every last chart All have their own release and release name.

Helm install charts To Kubernetes In the cluster , Each installation creates a new release. You can Helm Of chart repositories Looking for new chart.

Four 、 Common commands

• helm search： lookup Charts, You can go straight to Artifact Hub Search the website charts, helm search hub from Artifact Hub Find and list helm charts ,Helm The search uses a fuzzy string matching algorithm , So you can just type in part of the name
  • helm search hub - stay Artifact Hub Or your own hub Search for chart
  • helm search repo - Search in the warehouse you added
• helm install： To install a helm package , The simplest way to use it is to pass in two parameters ： You named it release Name and what you want to install chart The name of .
• helm upgrade and helm rollback： upgrade release And recover on failure
• helm uninstall： uninstall release
• helm repo：Helm 3 No longer comes with a default chart Warehouse .helm repo Provides a set of commands to add （helm repo add）、 List （helm repo list）、 to update （helm repo update） And remove the warehouse （helm repo remove）.

For more detailed commands, please refer to ：https://helm.sh/zh/docs/helm/helm/

5、 ... and 、 practice ：helm install mysql

1、 install helm

• Automated script installation

  install helm, Now use the script to install helm 3, For more installation methods, please refer to ：https://helm.sh/zh/docs/intro/install/

curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 | bash

• Compression pack installation

  • download Version needed ：https://github.com/helm/helm/releases
  • decompression (tar -zxvf helm-v3.9.0-linux-amd64.tar.gz)
  • Find... In unzip helm Program , Move to the desired directory (mv linux-amd64/helm /usr/local/bin/helm)

2、 add to chart Warehouse

#  Heavenly Sword  bitnami  Warehouse 
[[email protected] secret]# helm repo add bitnami https://charts.bitnami.com/bitnami
#  Add open source /Azure China 
[[email protected] secret]# helm repo add azure http://mirror.azure.cn/kubernetes/charts/
#  View the added warehouse 
[[email protected] secret]# helm repo list
NAME   	URL                                      
azure  	http://mirror.azure.cn/kubernetes/charts/
bitnami	https://charts.bitnami.com/bitnami  

3、 Inquire about mysql Available version

Find out what's available MySQL, You can go to Helm chart Warehouse Artifact Hub Find available MySQL, Such as ：https://artifacthub.io/packages/helm/bitnami/mysql, You can also use the following command to find

#  Inquire about  Artifact Hub  Available in  mysql chart
[[email protected] secret]# helm search hub mysql
URL                                               	CHART VERSION	APP VERSION  	DESCRIPTION                                       
https://artifacthub.io/packages/helm/cloudnativ...	5.0.1        	8.0.16       	Chart to create a Highly available MySQL cluster  
https://artifacthub.io/packages/helm/stakater/m...	1.0.6        	             	mysql chart that runs on kubernetes               
https://artifacthub.io/packages/helm/saber/mysql  	8.8.21       	8.0.27       	Chart to create a Highly available MySQL cluster 
#  Inquire about  repo  Warehouse available  mysql chart
[[email protected] secret]# helm search repo mysql
NAME                           	CHART VERSION	APP VERSION	DESCRIPTION                                       
azure/prometheus-mysql-exporter	0.7.1        	v0.11.0    	DEPRECATED A Helm chart for prometheus mysql ex...
bitnami/mysql                  	9.1.8        	8.0.29     	MySQL is a fast, reliable, scalable, and easy t...

4、 install MySQL

①、 Optional parameters

install MySQL, For more detailed parameters, please refer to https://artifacthub.io/packages/helm/bitnami/mysql

Parameters	explain	The default value is
MySQL Common parameters
auth.rootPassword	root Account password	""
auth.createDatabase	establish auth.database Specified database	true
auth.database	Database name	my_database
MySQL Main parameters
primary.persistence.storageClass	MySQL Host the long volume storage class	""
primary.persistence.annotations	MySQL Host long volume statement notes	{}
primary.persistence.accessModes	MySQL Host long volume access mode	["ReadWriteOnce"]
primary.persistence.size	MySQL Host long volume size	8Gi
MySQL Auxiliary parameter
secondary.service.type	service type	ClusterIP
secondary.service.ports.mysql	service port	3306
secondary.service.nodePorts.mysql	service nodePorts	""

②、 Parameter file

config.yaml The contents of the document are as follows ,YAML yes JSON Superset , You can also use JSON file

auth:
  createDatabase: true
  database: "study_database"
  rootPassword: "[email protected]"
primary:
  service:
    ports:
      mysql: "3306"
    type: "NodePort"
    nodePorts:
      mysql: "33060"
  persistence:
    storageClass: "nfs-storage"
    size: "1Gi"
    annotations: {
    }
    accessModes:
    - "ReadWriteMany"
    enabled: true

③、storageClass

among primary.persistence.storageClass=“nfs-storage” as follows , For specific implementation, please refer to another article ：K8S To configure storageclass Use nfs Dynamically claim local disk space

[[email protected] mysql]# kubectl get sc
NAME          PROVISIONER   RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
nfs-storage   nfs-diy       Retain          Immediate           false                  6d20h

[[email protected] mysql]# kubectl describe sc/nfs-storage
Name:            nfs-storage
IsDefaultClass:  No
Annotations:     kubectl.kubernetes.io/last-applied-configuration={
    "apiVersion":"storage.k8s.io/v1","kind":"StorageClass","metadata":{
    "annotations":{
    },"name":"nfs-storage"},"parameters":{
    "archiveOnDelete":"false"},"provisioner":"nfs-diy","reclaimPolicy":"Retain"}

Provisioner:           nfs-diy
Parameters:            archiveOnDelete=false
AllowVolumeExpansion:  <unset>
MountOptions:          <none>
ReclaimPolicy:         Retain
VolumeBindingMode:     Immediate
Events:                <none>

④、 install MySQL chart

#  install  MySQL,-f config.yaml  Specify the parameter file 
[[email protected] mysql]# helm install mysql bitnami/mysql -f config.yaml 
NAME: mysql
LAST DEPLOYED: Mon Jun 27 19:05:45 2022
NAMESPACE: default
STATUS: deployed
REVISION: 1
TEST SUITE: None
NOTES:
CHART NAME: mysql
CHART VERSION: 9.1.8
APP VERSION: 8.0.29

** Please be patient while the chart is being deployed **

Tip:

  Watch the deployment status using the command: kubectl get pods -w --namespace default

Services:

  echo Primary: mysql.default.svc.cluster.local:3306

Execute the following to get the administrator credentials:

  echo Username: root
  MYSQL_ROOT_PASSWORD=$(kubectl get secret --namespace default mysql -o jsonpath="{.data.mysql-root-password}" | base64 -d)

To connect to your database:

  1. Run a pod that you can use as a client:

      kubectl run mysql-client --rm --tty -i --restart='Never' --image  docker.io/bitnami/mysql:8.0.29-debian-11-r3 --namespace default --env MYSQL_ROOT_PASSWORD=$MYSQL_ROOT_PASSWORD --command -- bash

  2. To connect to primary service (read/write):

      mysql -h mysql.default.svc.cluster.local -uroot -p"$MYSQL_ROOT_PASSWORD"
#  see  pod  details 
[[email protected] mysql]# kubectl get pod -o wide
NAME                                      READY   STATUS             RESTARTS          AGE     IP            NODE    NOMINATED NODE   READINESS GATES
mysql-0                                   1/1     Running            0                 105s    10.244.1.57   node1   <none>           <none>
#  see  PVC
[[email protected] mysql]# kubectl get pvc
NAME                 STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
data-mysql-0         Bound    pvc-e9484bd1-9ec2-4f09-8d71-d7bd1342792b   1Gi        RWX            nfs-storage    15s
#  see  PV
[[email protected] mysql]# kubectl get pv
NAME                                       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS     CLAIM                        STORAGECLASS   REASON   AGE
pvc-9e1650f2-4f5b-4c14-95c2-eb046ebddb2c   8Gi        RWO            Retain           Released   default/data-mysql-0         nfs-storage             85m
#  Mounted Directory 
[[email protected] mysql]# ls /home/data/default-data-mysql-0-pvc-e9484bd1-9ec2-4f09-8d71-d7bd1342792b/data/
auto.cnf       binlog.000002  binlog.index  ca.pem           client-key.pem     #ib_16384_1.dblwr ibdata1 ib_logfile1 #innodb_temp mysql.ibd performance_schema public_key.pem server-key.pem sys undo_002
binlog.000001  binlog.000003  ca-key.pem    client-cert.pem  #ib_16384_0.dblwr ib_buffer_pool ib_logfile0 ibtmp1 mysql mysql_upgrade_info private_key.pem server-cert.pem study_database undo_001

#  see  SVC
[[email protected] mysql]# kubectl get svc
NAME                                   TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
mysql                                  NodePort    10.96.52.109    <none>        3306:33060/TCP   26s
mysql-headless                         ClusterIP   None            <none>        3306/TCP         26s

⑤、 Connect the test

• The command line connection is as follows , You can see that the connection is successful , And create study_database database

#  Create a  MySQL pod, Exit to delete 
[[email protected] mysql]# kubectl run mysql-client --rm --tty -i --restart='Never' --image docker.io/bitnami/mysql:8.0.29-debian-11-r3 --namespace default --env [email protected] --command -- bash
If you don't see a command prompt, try pressing enter. I have no [email protected]:/$ mysql -h mysql.default.svc.cluster.local -uroot -p Enter password: Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 352 Server version: 8.0.29 Source distribution Copyright (c) 2000, 2022, 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 |
| mysql              |
| performance_schema |
| study_database     |
| sys                |
+--------------------+
5 rows in set (0.00 sec)

mysql> 

• Visual interface sqlyog Successful connection , Port number 33060
  

5、 uninstall mysql

Uninstall using the following command mysql, Will delete pod and service, But it will not be deleted PV 、 PVC and SC,PV The state will change to Released

[[email protected] mysql]# helm uninstall mysql
release "mysql" uninstalled