Charmed MySQL Tutorial > 2. Deploy MySQL
Deploy Charmed MySQL
In this section, you will deploy Charmed MySQL, access a unit, and interact with the MySQL databases that exist inside the application.
Summary
Deploy MySQL
To deploy Charmed MySQL, run the following command:
juju deploy mysql
Juju will now fetch Charmed MySQL from Charmhub and deploy it to the LXD cloud. 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 status
documentation for more information about its usage.
When the application is ready, juju status
will show the mysql
app as active
and the mysql/0*
unit as idle
, like the example below:
Model Controller Cloud/Region Version SLA Timestamp
tutorial overlord localhost/localhost 3.1.6 unsupported 00:52:59+02:00
App Version Status Scale Charm Channel Rev Exposed Message
mysql 8.0.32-0ubun... active 1 mysql 8.0/stable 151 no Primary
Unit Workload Agent Machine Public address Ports Message
mysql/0* active idle 1 10.234.188.135 3306,33060/tcp Primary
Machine State Address Inst id Base AZ Message
1 started 10.234.188.135 juju-ff9064-0 ubuntu@22.04 Running
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/leader get-password
Example output:
...
password: yWJjs2HccOmqFMshyRcwWnjF
username: root
To request a password for a different user, use the option username
:
juju run mysql/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 Machine Public address Ports Message
mysql/0* active idle 1 10.234.188.135 3306,33060/tcp Primary
...
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/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 -pyWJjs2HccOmqFMshyRcwWnjF
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+D
or 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 |
+-------------------------+--------------+
| 8.0.32-0ubuntu0.22.04.2 | 2023-01-29 |
+-------------------------+--------------+
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
. Once you’ve typedexit
you will be back in the host of Charmed MySQL (mysql/0
). Exit this host by once again typingexit
. Now you will be in your original shell where you first started the tutorial; here you can interact with Juju and LXD.
Next step: 3. Scale your replicas