Restore the backup¶

The following steps describe how to restore your backup to another Percona Server container and check whether the data is available.

Create another Docker volume
```
$ docker volume create myvol2
```
Expected output
```
myvol2
```

Run another Percona Server container to restore the backup to

Option	Description
`--name`	Provides a name to the container. If you do not use this option, Docker adds a random name.
`-d`	Detaches the container. The container runs in the background.
`-e`	Adds an environmental variable. This example adds the `MYSQL_ROOT_PASSWORD` environment variable. The instance refuses to initialize if no environmental variable is added. Choose a more secure password, if needed.
`myvol2`	Indicates the persistent storage for the database.
`8.4`	Use this tag to specify a specific version.

You must provide at least one environment variable to access the database, such as MYSQL_ROOT_PASSWORD, MYSQL_DATABASE, MYSQL_USER, and MYSQL_PASSWORD or the instance refuses to initialize.

For this document, we are using the 8.4 tag. In Docker, a tag is a label assigned to an image. Tags are used to maintain different versions of an image. If we did not add a tag, Docker uses latest as the default tag and downloads the latest image from [percona/percona-server on the Docker Hub].

To use a Docker volume for persistent storage with a database, specify the path where the database stores its data inside the container, usually /var/lib/mysql.

Run a Docker container example

$ docker run -d -p 3307:3306 --name psmysql2 -e MYSQL_ROOT_PASSWORD=secret -v myvol2:/var/lib/mysql percona/percona-server:8.4

Expected output

4501d5524461b4483d414bd218d49ed4f47599add7d7fb81e157951a7a52f3d1

Stop psmysql2 container
```
$ docker stop psmysql2
```
Expected output
```
psmysql2
```
Remove all created files in myvol2 to allow xtrabackup restore data to myvol2

The --rm option automatically removes the temporary container created from percona/percona-xtrabackup:8.0.34 image after the container exits.
```
$ docker run --volumes-from psmysql2 -v backupvol:/backup_84 -it --rm --user root percona/percona-xtrabackup:8.4 /bin/bash -c "rm -rf /var/lib/mysql/*"
```
If the command executes successfully, the expected output is empty.

Restore backup of psmysql from backupvol to a new psmysql2 instance.

$ docker run --platform linux/amd64 --volumes-from psmysql2 -v backupvol:/backup_84 -it --rm --user root percona/percona-xtrabackup:8.4 /bin/bash -c "xtrabackup --copy-back --datadir=/var/lib/mysql/ --target-dir=/backup_84"

Expected output

2024-10-07T14:08:59.127166-00:00 0 [Note] [MY-011825] [Xtrabackup] recognized server arguments: --datadir=/var/lib/mysql/
2024-10-07T14:08:59.128951-00:00 0 [Note] [MY-011825] [Xtrabackup] recognized client arguments: --copy-back=1 --target-dir=/backup_84
xtrabackup version 8.4.0-1 based on MySQL server 8.4.0 Linux (x86_64) (revision id: 3792f907)
2024-10-07T14:08:59.129407-00:00 0 [Note] [MY-011825] [Xtrabackup] cd to /backup_84/

...

2024-10-07T14:08:59.129407-00:00 0 1 [Note] [MY-011825] [Xtrabackup] Done: Copying ./ibtmp1 to /var/lib/mysql/ibtmp1 

2024-10-07T14:08:59.129407-00:00 0 [Note] [MY-011825] [Xtrabackup] completed OK!

This command restores the backup files from the backup_8034 volume to the psmysql2 container. It uses the percona/percona-xtrabackup:8.0.34 image to run a temporary container with root privileges. It executes the xtrabackup tool with the --copy-back option, which copies the files from the backup_8034 volume to the /var/lib/mysql/ directory in the psmysql2 container. The command uses –rm option to delete the temporary container after it exits.

Validate the backup¶

This section describes the backup validation steps assuming that you backed up mydb database with the employees table as we have in our example. The validation steps may vary depending on your data set.

Change the owner of the files in myvol2 from root to mysql

To avoid permission issues when running psmysql2 container, you need to change the owner because the files were restored by root user and psmysql2 will use mysql user.
```
$ docker run --volumes-from psmysql2 -v backupvol:/backup_84 -it --rm --user root percona/percona-xtrabackup:8.4 /bin/bash -c "chown -R mysql:mysql /var/lib/mysql/" 
```
If the command executes successfully, the expected output is empty.
Start the psmysql2 container
```
$ docker start psmysql2
```
Expected output
```
psmysql2
```

Connect to the database instance.

For this example, we have the following options:

Option	Description
`it`	Interact with the container and be a pseudo-terminal
`psmysql2`	Running container name
`mysql`	Connects to a database instance
`-u`	Specifies the user account used to connect
`-p`	Use this password when connecting

Connect to the database instance example

$ docker exec -it psmysql2 mysql -uroot -p

You are prompted to enter the password, which is secret.

Enter password:

You should see the following result.

Expected output

Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 10
Server version: 8.4.0-1 Percona Server (GPL), Release 1, Revision 238b3c02

Copyright (c) 2009-2024 Percona LLC and/or its affiliates
Copyright (c) 2000, 2024, 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.

Check the list of databases to make sure, the backed up, mydb database is in the list.

mysql> show databases;

Expected output

+--------------------+ 

| Database           | 

+--------------------+ 

| information_schema | 

| mydb               | 

| mysql              | 

| performance_schema | 

| sys                | 

+--------------------+ 

5 rows in set (0.03 sec)

Use the mydb database.
```
mysql> use mydb; 
```
Expected output
```
Database changed
```

Check that your table contains data

mysql> SELECT * FROM employees;

Expected output

+----+--------------------+-----------------------------------+-------------+ 

| id | name               | email                             | country     | 

+----+--------------------+-----------------------------------+-------------+ 

|  1 | Erasmus Richardson | [email protected] | England     | 

|  2 | Jenna French       | [email protected]        | Canada      | 

|  3 | Alfred Dejesus     | [email protected]                  | Austria     | 

|  4 | Hamilton Puckett   | [email protected]          | Canada      | 

|  5 | Michal Brzezinski  | [email protected]                   | Poland      | 

|  6 | Zofia Lis          | [email protected]               | Poland      | 

|  7 | Aisha Yakubu       | [email protected]             | Nigeria     | 

|  8 | Miguel Cardenas    | [email protected]                 | Peru        | 

|  9 | Luke Jansen        | [email protected]                  | Netherlands | 

| 10 | Roger Pettersen    | [email protected]                | Norway      | 

+----+--------------------+-----------------------------------+-------------+ 

10 rows in set (0.00 sec)

Next steps¶

Clean up