Charmed MySQL K8s Tutorial > 2. Deploy MySQL
Deploy Charmed MySQL
In this section, you will deploy Charmed MySQL K8s, access a unit, and interact with the MySQL databases that exist inside the application.
Summary
Deploy MySQL
To deploy Charmed MySQL K8s, run the following command:
juju deploy mysql-k8s --trust
The
--trustflag is necessary to create some K8s resources
Juju will now fetch Charmed MySQL K8s from Charmhub and deploy it to MicroK8s. This process can take several minutes depending on how provisioned (RAM, CPU, etc) your machine is. You can track the progress by running:
juju status --watch 1s
This command is useful for checking the real-time information about the state of a charm and the machines hosting it. Check the
juju statusdocumentation for more information about its usage.
When the application is ready, juju status will show the mysql app as active and the mysql-k8s/0* unit as idle, like the example below:
Model Controller Cloud/Region Version SLA Timestamp
tutorial overlord microk8s/localhost 3.5.2 unsupported 22:33:45+01:00
App Version Status Scale Charm Channel Rev Address Exposed Message
mysql-k8s 8.0.31 active 1 mysql-k8s 8.0/stable 36 10.152.183.234 no Unit is ready: Mode: RW
Unit Workload Agent Address Ports Message
mysql-k8s/0* active idle 10.1.84.74 Unit is ready: Mode: RW
To exit the screen with
juju status --watch 1s, enterCtrl+C.
You can also watch juju logs with the juju debug-log command. More info on logging in the juju logs documentation.
Access MySQL
Warning: This part of the tutorial accesses MySQL via the root user.
Do not directly interface with the root user in a production environment.
In a later section about integrations, we will cover how to safely access MySQL via a separate user.
The easiest way to access MySQL is via the MySQL Command-Line Client (mysql). For this, we must first retrieve the credentials.
Retrieve credentials
Connecting to the database requires that you know the values for host (IP address), username and password.
To retrieve username and password, run the Juju action get-password on the leader unit as follows:
juju run mysql-k8s/leader get-password
Example output:
unit-mysql-k8s-0:
UnitId: mysql-k8s/0
id: "2"
results:
password: sQI3Ojih7uL5UC4J1D9Xuqgx
username: root
status: completed
timing:
completed: 2023-02-15 21:35:56 +0000 UTC
enqueued: 2023-02-15 21:35:55 +0000 UTC
started: 2023-02-15 21:35:55 +0000 UTC
To request a password for a different user, use the option username:
juju run mysql-k8s/leader get-password username=<username>
To retrieve the host’s IP address, run juju status. This should be listed under the “Public address” of the unit hosting the MySQL application:
...
Unit Workload Agent Address Ports Message
mysql-k8s/0* active idle 10.1.84.74 Unit is ready: Mode: RW
...
Access MySQL via the mysql client
To access the unit hosting Charmed MySQL, one could normally use the following command:
mysql -h <ip_address> -u<username> -p<password>
However, this is not possible with the root user. For security reasons, the root user is restricted to only allow connections from localhost.
The way to access MySQL server with the root user is to first ssh into the primary Juju unit:
juju ssh mysql-k8s/leader
In this case, we know the primary unit is the juju leader unit, since it is the only existing unit.
In a cluster with more units, the primary is not necessarily equivalent to the leader. To identify the primary unit in a cluster, run
juju run mysql/<any_unit> get-cluster-status. This will display the entire cluster topology.
Once inside the Juju virtual machine, the root user can access MySQL by calling
mysql -h 127.0.0.1 -uroot -psQI3Ojih7uL5UC4J1D9Xuqgx
Remember, your password will be different to the example above. Make sure to insert it without a space as
-p<password>
You will then see the mysql> command prompt, similar to the output below:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 56
Server version: 8.0.32-0ubuntu0.22.04.2 (Ubuntu)
Copyright (c) 2000, 2023, 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>
If at any point you’d like to leave the mysql client, enter
Ctrl+Dor typeexit.
You can now interact with MySQL directly using any MySQL Queries. For example entering SELECT VERSION(), CURRENT_DATE; should output something like:
mysql> SELECT VERSION(), CURRENT_DATE;
+-------------------------+--------------+
| VERSION() | CURRENT_DATE |
+-------------------------+--------------+
| 8.0.31-0ubuntu0.22.04.1 | 2023-02-15 |
+-------------------------+--------------+
1 row in set (0.00 sec)
Feel free to test out any other MySQL queries. When you’re ready to leave the MySQL shell you can just type exit. Now you will be in your original shell where you first started the tutorial; here you can interact with Juju and MicroK8s.
Next step: 3. Scale your replicas