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Load Balance MySQL Group Replication Using ProxySQL
ProxySQL supports load balancing for MySQL Group Replication. This guide will show you how you can load balance MySQL Group Replication using ProxySQL.
Before You Begin
Before proceeding:
- Read mysql group replication concept to learn about MySQL Group Replication.
- You need to have a Kubernetes cluster, and the
kubectlcommand-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 operator in your cluster following the steps here.
- You have to be familiar with the ProxySQL CRD.
To keep things isolated, we are going to use a separate namespace called demo throughout this tutorial. Create demo namespace if you haven’t created yet.
$ kubectl create ns demo
namespace/demo created
Note: YAML files used in this tutorial are stored here.
Load Balance Using ProxySQL
This section will demonstrate how to load balance a MySQL Group Replication (both the single-primary mode and multi-primary mode) using ProxySQL. Since KubeDB currently supports group replication only for the single-primary mode, we we are going to deploy a single-primary MySQL replication group using KubeDB. Then, we are going to load balance the read-write query requests to the MySQL database using ProxySQL.
Deploy Sample MySQL Group Replication
Let’s deploy a sample MySQL Group Replication and insert some data into it.
Create MySQL Object
Below is the YAML of a sample MySQL object with group replication that we are going to create for this tutorial:
apiVersion: kubedb.com/v1alpha2
kind: MySQL
metadata:
name: my-group
namespace: demo
spec:
version: "5.7.36"
replicas: 3
topology:
mode: GroupReplication
group:
name: "dc002fc3-c412-4d18-b1d4-66c1fbfbbc9b"
storageType: Durable
storage:
storageClassName: standard
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
terminationPolicy: WipeOut
Create the above MySQL object,
$ kubectl create -f https://github.com/kubedb/docs/raw/v2021.12.21/docs/examples/proxysql/demo-my-group.yaml
mysql.kubedb.com/my-group created
KubeDB will deploy a single primary MySQL Group Replication according to the above specification. It will also create the necessary Secrets and Services to access the database.
Let’s check if the database is ready to use,
$ kubectl get my -n demo my-group
NAME VERSION STATUS AGE
my-group 5.7.25 Running 5m37s
The database is Running. Verify that KubeDB has created necessary Secret for this database using the following commands,
$ kubectl get secret -n demo -l=app.kubernetes.io/instance=my-group
NAME TYPE DATA AGE
my-group-auth Opaque 2 10m
Here, we have to use the secret my-group-auth to connect with the database.
Insert Sample Data
Now, we are going to exec into the database pod and create some sample data. At first, find out the database Pod using the following command,
$ kubectl get pods -n demo --selector="app.kubernetes.io/instance=my-group"
NAME READY STATUS RESTARTS AGE
my-group-0 1/1 Running 0 12m
my-group-1 1/1 Running 0 12m
my-group-2 1/1 Running 0 12m
Copy the username and password of the root user to access into mysql shell.
$ kubectl get secret -n demo my-group-auth -o jsonpath='{.data.username}'| base64 -d
root⏎
$ kubectl get secret -n demo my-group-auth -o jsonpath='{.data.password}'| base64 -d
tiIKEbjwnKLxAJP9⏎
Now, let’s exec into the Pod to enter into mysql shell and create a database and a table,
$ kubectl exec -it -n demo my-group-0 -- mysql --user=root --password=tiIKEbjwnKLxAJP9
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 25395
Server version: "5.7.33"-log MySQL Community Server (GPL)
Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
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> CREATE DATABASE playground;
Query OK, 1 row affected (0.04 sec)
mysql> SHOW DATABASES;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| playground |
| sys |
+--------------------+
5 rows in set (0.00 sec)
mysql> CREATE TABLE playground.equipment ( id INT NOT NULL AUTO_INCREMENT, type VARCHAR(50), quant INT, color VARCHAR(25), PRIMARY KEY(id));
Query OK, 0 rows affected (0.08 sec)
mysql> SHOW TABLES IN playground;
+----------------------+
| Tables_in_playground |
+----------------------+
| equipment |
+----------------------+
1 row in set (0.00 sec)
mysql> INSERT INTO playground.equipment (type, quant, color) VALUES ("slide", 2, "blue");
Query OK, 1 row affected (0.02 sec)
mysql> SELECT * FROM playground.equipment;
+----+-------+-------+-------+
| id | type | quant | color |
+----+-------+-------+-------+
| 7 | slide | 2 | blue |
+----+-------+-------+-------+
1 row in set (0.00 sec)
mysql> exit
Bye
Now, we are ready to see how ProxySQL can load balance the MySQL requests and route according to the defined rules.
Prepare ProxySQL
KubeDB has a CRD named ProxySQL that can identify the reads, writes and route the write traffic to master and read traffic between the available slaves. We just need to create a ProxySQL object pointing to the backend database object.
Create ProxySQL Object
Let’s create a ProxySQL object called proxy-my-group pointing to the previously created MySQL database. Below is the YAML of the ProxySQL object we are going to create,
apiVersion: kubedb.com/v1alpha2
kind: ProxySQL
metadata:
name: proxy-my-group
namespace: demo
spec:
version: "2.0.4"
replicas: 1
mode: GroupReplication
backend:
ref:
apiGroup: "kubedb.com"
kind: MySQL
name: my-group
replicas: 3
Now, create this,
$ kubectl create -f https://github.com/kubedb/docs/raw/v2021.12.21/docs/examples/proxysql/demo-proxy-my-group.yaml
proxysql.kubedb.com/proxy-my-group created
Verify ProxySQL Creation
KubeDB will deploy one replica for proxysql pointing to backend MySQL servers as we specified .spec.backend.ref as the previously created MySQL object named my-group. KubeDB will also create a Secret and a Service for it.
Let’s check if the ProxySQL object is ready to use,
$ kubectl get proxysql -n demo proxy-my-group
NAME VERSION STATUS AGE
proxy-my-group 2.0.4 Running 129m
The status is Running. Verify that KubeDB has created necessary Secret and Service for this object using the following commands,
$ kubectl get secret -n demo -l=proxysql.app.kubernetes.io/instance=proxy-my-group
NAME TYPE DATA AGE
proxy-my-group-auth Opaque 2 132m
$ kubectl get service -n demo -l=proxysql.app.kubernetes.io/instance=proxy-my-group
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
proxy-my-group ClusterIP 10.32.6.128 <none> 6033/TCP 133m
Here, we have to use service proxy-my-group and secret proxy-my-group-auth to connect with the database through proxysql.
Route Read/Write Requests through ProxySQL
So, KubeDB creates two different users (proxysql and admin) in the MySQL database for proxysql. The admin user is responsible for setting up admin configuration for proxysql and the proxysql user is for requesting query to the MySQL servers. KubeDB stores the credentials of proxysql user in the Secret proxy-my-group-auth, where the username and password of the admin user are fixed and they are admin and admin respectively.
kubectl describe secret -n demo proxy-my-group-auth
Name: proxy-my-group-auth
Namespace: demo
Labels: app.kubernetes.io/name=proxysqls.kubedb.com
proxysql.kubedb.com/load-balance=GroupReplication
proxysql.app.kubernetes.io/instance=proxy-my-group
Annotations: <none>
Type: Opaque
Data
====
proxysqlpass: 16 bytes
proxysqluser: 8 bytes
Copy the username and password of the proxysql user to access into mysql shell.
$ kubectl get secret -n demo proxy-my-group-auth -o jsonpath='{.data.proxysqluser}'| base64 -d
proxysql⏎
$ kubectl get secret -n demo proxy-my-group-auth -o jsonpath='{.data.proxysqlpass}'| base64 -d
jxOlSObHgvvjOk1v⏎
Reads
Now, let’s exec into the proxysql Pod to enter into mysql shell using proxysql user credentials and read the existing database and table,
$ kubectl exec -it -n demo proxy-my-group-0 -- mysql --user=proxysql --password=jxOlSObHgvvjOk1v --host proxy-my-group.demo --port=6033 --prompt='MySQL [proxysql]> '
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MySQL connection id is 9
Server version: 5.5.30 (ProxySQL)
Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MySQL [proxysql]> SHOW DATABASES;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| playground |
| sys |
+--------------------+
5 rows in set (0.00 sec)
MySQL [proxysql]> SHOW TABLES IN playground;
+----------------------+
| Tables_in_playground |
+----------------------+
| equipment |
+----------------------+
1 row in set (0.00 sec)
MySQL [proxysql]> SELECT * FROM playground.equipment;
+----+-------+-------+-------+
| id | type | quant | color |
+----+-------+-------+-------+
| 7 | slide | 2 | blue |
+----+-------+-------+-------+
1 row in set (0.00 sec)
MySQL [proxysql]> exit
Bye
Exec into the Pod to enter into mysql shell using admin user credentials and see the query counts,
kubectl exec -it -n demo proxy-my-group-0 -- mysql --user=admin --password=admin --host 127.0.0.1 --port=6032 --prompt='MySQL [admin]> '
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MySQL connection id is 12
Server version: 5.5.30 (ProxySQL Admin Module)
Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MySQL [admin]> SELECT command, Total_Time_us, Total_cnt FROM stats_mysql_commands_counters;
+-------------------+---------------+-----------+
| Command | Total_Time_us | Total_cnt |
+-------------------+---------------+-----------+
| ALTER_TABLE | 0 | 0 |
| ALTER_VIEW | 0 | 0 |
| ANALYZE_TABLE | 0 | 0 |
| BEGIN | 0 | 0 |
| CALL | 0 | 0 |
| CHANGE_MASTER | 0 | 0 |
| COMMIT | 0 | 0 |
| CREATE_DATABASE | 0 | 0 |
| CREATE_INDEX | 0 | 0 |
| CREATE_TABLE | 0 | 0 |
| CREATE_TEMPORARY | 0 | 0 |
| CREATE_TRIGGER | 0 | 0 |
| CREATE_USER | 0 | 0 |
| CREATE_VIEW | 0 | 0 |
| DEALLOCATE | 0 | 0 |
| DELETE | 0 | 0 |
| DESCRIBE | 0 | 0 |
| DROP_DATABASE | 0 | 0 |
| DROP_INDEX | 0 | 0 |
| DROP_TABLE | 0 | 0 |
| DROP_TRIGGER | 0 | 0 |
| DROP_USER | 0 | 0 |
| DROP_VIEW | 0 | 0 |
| GRANT | 0 | 0 |
| EXECUTE | 0 | 0 |
| EXPLAIN | 0 | 0 |
| FLUSH | 0 | 0 |
| INSERT | 0 | 0 |
| KILL | 0 | 0 |
| LOAD | 0 | 0 |
| LOCK_TABLE | 0 | 0 |
| OPTIMIZE | 0 | 0 |
| PREPARE | 0 | 0 |
| PURGE | 0 | 0 |
| RENAME_TABLE | 0 | 0 |
| RESET_MASTER | 0 | 0 |
| RESET_SLAVE | 0 | 0 |
| REPLACE | 0 | 0 |
| REVOKE | 0 | 0 |
| ROLLBACK | 0 | 0 |
| SAVEPOINT | 0 | 0 |
| SELECT | 3789 | 7 |
| SELECT_FOR_UPDATE | 0 | 0 |
| SET | 0 | 0 |
| SHOW_TABLE_STATUS | 0 | 0 |
| START_TRANSACTION | 0 | 0 |
| TRUNCATE_TABLE | 0 | 0 |
| UNLOCK_TABLES | 0 | 0 |
| UPDATE | 0 | 0 |
| USE | 0 | 0 |
| SHOW | 5964 | 2 |
| UNKNOWN | 401 | 1 |
+-------------------+---------------+-----------+
52 rows in set (0.00 sec)
MySQL [admin]> exit
Bye
Writes
This time exec into the proxysql Pod to enter into mysql shell using proxysql user credentials to create new database and table,
kubectl exec -it -n demo proxy-my-group-0 -- mysql --user=proxysql --password=jxOlSObHgvvjOk1v --host proxy-my-group.demo --port=6033 --prompt='MySQL [proxysql]> '
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MySQL connection id is 13
Server version: 5.5.30 (ProxySQL)
Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MySQL [proxysql]> CREATE DATABASE playground_new;
Query OK, 1 row affected (0.05 sec)
MySQL [proxysql]> CREATE TABLE playground_new.equipment_new ( id INT NOT NULL AUTO_INCREMENT, type VARCHAR(50), quant INT, color VARCHAR(25), PRIMARY KEY(id));
Query OK, 0 rows affected (0.16 sec)
MySQL [proxysql]> INSERT INTO playground_new.equipment_new (type, quant, color) VALUES ("slide_new", 2, "blue");
Query OK, 1 row affected (0.04 sec)
MySQL [proxysql]> SELECT * FROM playground_new.equipment_new;
+----+-----------+-------+-------+
| id | type | quant | color |
+----+-----------+-------+-------+
| 7 | slide_new | 2 | blue |
+----+-----------+-------+-------+
1 row in set (0.00 sec)
MySQL [proxysql]> exit;
Bye
Again, exec into the Pod to enter into mysql shell using admin user credentials and see the query counts,
kubectl exec -it -n demo proxy-my-group-0 -- mysql --user=admin --password=admin --host 127.0.0.1 --port=6032 --prompt='MySQL [admin]> '
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MySQL connection id is 14
Server version: 5.5.30 (ProxySQL Admin Module)
Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MySQL [admin]> SELECT command, Total_Time_us, Total_cnt FROM stats_mysql_commands_counters;
+-------------------+---------------+-----------+
| Command | Total_Time_us | Total_cnt |
+-------------------+---------------+-----------+
| ALTER_TABLE | 0 | 0 |
| ALTER_VIEW | 0 | 0 |
| ANALYZE_TABLE | 0 | 0 |
| BEGIN | 0 | 0 |
| CALL | 0 | 0 |
| CHANGE_MASTER | 0 | 0 |
| COMMIT | 0 | 0 |
| CREATE_DATABASE | 46214 | 1 |
| CREATE_INDEX | 0 | 0 |
| CREATE_TABLE | 158931 | 1 |
| CREATE_TEMPORARY | 0 | 0 |
| CREATE_TRIGGER | 0 | 0 |
| CREATE_USER | 0 | 0 |
| CREATE_VIEW | 0 | 0 |
| DEALLOCATE | 0 | 0 |
| DELETE | 0 | 0 |
| DESCRIBE | 0 | 0 |
| DROP_DATABASE | 0 | 0 |
| DROP_INDEX | 0 | 0 |
| DROP_TABLE | 0 | 0 |
| DROP_TRIGGER | 0 | 0 |
| DROP_USER | 0 | 0 |
| DROP_VIEW | 0 | 0 |
| GRANT | 0 | 0 |
| EXECUTE | 0 | 0 |
| EXPLAIN | 0 | 0 |
| FLUSH | 0 | 0 |
| INSERT | 34228 | 1 |
| KILL | 0 | 0 |
| LOAD | 0 | 0 |
| LOCK_TABLE | 0 | 0 |
| OPTIMIZE | 0 | 0 |
| PREPARE | 0 | 0 |
| PURGE | 0 | 0 |
| RENAME_TABLE | 0 | 0 |
| RESET_MASTER | 0 | 0 |
| RESET_SLAVE | 0 | 0 |
| REPLACE | 0 | 0 |
| REVOKE | 0 | 0 |
| ROLLBACK | 0 | 0 |
| SAVEPOINT | 0 | 0 |
| SELECT | 8388 | 9 |
| SELECT_FOR_UPDATE | 0 | 0 |
| SET | 0 | 0 |
| SHOW_TABLE_STATUS | 0 | 0 |
| START_TRANSACTION | 0 | 0 |
| TRUNCATE_TABLE | 0 | 0 |
| UNLOCK_TABLES | 0 | 0 |
| UPDATE | 0 | 0 |
| USE | 0 | 0 |
| SHOW | 6713 | 3 |
| UNKNOWN | 401 | 1 |
+-------------------+---------------+-----------+
52 rows in set (0.00 sec)
MySQL [admin]> exit
Bye
Cleanup
To clean up the Kubernetes resources created by this tutorial, run:
$ kubectl delete proxysql -n demo proxy-my-group
$ kubectl delete my -n demo my-group
Next Steps
- Monitor ProxySQL with KubeDB using out-of-the-box builtin-Prometheus.
- Monitor ProxySQL with KubeDB using out-of-the-box Prometheus operator.
- Use private Docker registry to deploy ProxySQL with KubeDB here.
- Use custom config file to configure ProxySQL here.
- Detail concepts of ProxySQL CRD here.
- Detail concepts of ProxySQLVersion CRD here.
- Want to hack on KubeDB? Check our contribution guidelines.