###############################
# MYSQL 8.0.x → 8.4.x UPGRADE
# CLEAN INSTALL + RESTORE METHOD
###############################

ENVIRONMENT:
- RHEL8 / Rocky Linux
- Custom datadir: /data/mysql_server
- No GTID
- Old MySQL 8.0.x
- New MySQL 8.4.x
- Using encryption/keyring
- Fresh initialize method

====================================================
STEP 1 — CHECK OLD MYSQL ENVIRONMENT
====================================================

mysql -uroot -p

SHOW PLUGINS;

SELECT TABLE_SCHEMA,TABLE_NAME,CREATE_OPTIONS
FROM information_schema.tables
WHERE CREATE_OPTIONS LIKE '%ENCRYPTION%';

grep -Ri keyring /etc/my.cnf*

====================================================
STEP 2 — TAKE FULL BACKUP
====================================================

mysqldump \
--all-databases \
--routines \
--events \
--triggers \
--single-transaction \
--hex-blob \
-u root -p > /backup/full.sql

====================================================
STEP 3 — BACKUP KEYRING (VERY IMPORTANT)
====================================================

tar -cvzf /backup/mysql-keyring.tar.gz \
/data/mysql-keyring

====================================================
STEP 4 — BACKUP CONFIG
====================================================

cp -p /etc/my.cnf /backup/

====================================================
STEP 5 — REMOVE ENCRYPTION FROM DUMP
(RECOMMENDED SAFEST METHOD)
====================================================

cp /backup/full.sql /backup/full_no_encrypt.sql

sed -i "s/ENCRYPTION='Y'/ENCRYPTION='N'/g" \
/backup/full_no_encrypt.sql

====================================================
STEP 6 — STOP MYSQL
====================================================

systemctl stop mysqld

ps -ef | grep mysqld

IF STILL RUNNING:

pkill -9 mysqld

====================================================
STEP 7 — REMOVE OLD MYSQL RPMs
====================================================

rpm -qa | grep -i mysql

dnf remove mysql*

OR

rpm -e mysql-community-server \
mysql-community-client \
mysql-community-common \
mysql-community-libs

====================================================
STEP 8 — INSTALL MYSQL 8.4 RPMs
====================================================

cd /data/pkg/mysql84/

yum install mysql-community-*.rpm

OR

rpm -ivh mysql-community-common-8.4*.rpm
rpm -ivh mysql-community-client-plugins-8.4*.rpm
rpm -ivh mysql-community-libs-8.4*.rpm
rpm -ivh mysql-community-client-8.4*.rpm
rpm -ivh mysql-community-server-8.4*.rpm

====================================================
STEP 9 — RENAME OLD DATADIR
====================================================

mv /data/mysql_server \
/data/mysql_server_80_backup

====================================================
STEP 10 — CREATE NEW DATADIR
====================================================

mkdir -p /data/mysql_server

chown -R mysql:mysql /data/mysql_server

chmod 750 /data/mysql_server

====================================================
STEP 11 — EDIT /etc/my.cnf
====================================================

REMOVE OLD KEYRING CONFIG:

#early-plugin-load=keyring_file.so
#keyring_file_data=/data/mysql-keyring/keyring

====================================================
STEP 12 — CREATE NEW KEYRING DIRECTORY
====================================================

mkdir -p /data/mysql-keyring

chown -R mysql:mysql /data/mysql-keyring

chmod 750 /data/mysql-keyring

====================================================
STEP 13 — CREATE COMPONENT CONFIG
====================================================

mkdir -p /var/lib/mysql-files

vi /var/lib/mysql-files/component_keyring_file.cnf

ADD:

{
  "path": "/data/mysql-keyring/keyring",
  "read_only": false
}

SAVE FILE

====================================================
STEP 14 — FIX PERMISSIONS
====================================================

chown mysql:mysql \
/var/lib/mysql-files/component_keyring_file.cnf

chmod 640 \
/var/lib/mysql-files/component_keyring_file.cnf

Here before create check which path of plugins MySQL takes from like 

====================================================
STEP 15 — CREATE BOOTSTRAP FILE
(VERY IMPORTANT)
====================================================

vi /usr/sbin/mysqld.my

ADD:

{
  "components": "file://component_keyring_file"
}

SAVE FILE

====================================================
STEP 16 — FIX BOOTSTRAP FILE PERMISSIONS
====================================================

chown mysql:mysql /usr/sbin/mysqld.my

chmod 640 /usr/sbin/mysqld.my

====================================================
STEP 17 — INITIALIZE MYSQL 8.4
====================================================

mysqld \
--defaults-file=/etc/my.cnf \
--initialize \
--user=mysql

====================================================
STEP 18 — START MYSQL
====================================================

systemctl start mysqld

====================================================
STEP 19 — CHECK LOGS
====================================================

journalctl -xeu mysqld

tail -f /data/mysql_server/mysqld.log

====================================================
STEP 20 — LOGIN MYSQL
====================================================

mysql -uroot -p

====================================================
STEP 21 — VERIFY KEYRING COMPONENT
====================================================

SELECT * FROM performance_schema.keyring_component_status;

IF NOT EMPTY = SUCCESS

====================================================
STEP 22 — REGISTER COMPONENT
====================================================

INSTALL COMPONENT 'file://component_keyring_file';

SELECT * FROM mysql.component;

====================================================
STEP 23 — TEST ENCRYPTION
====================================================

CREATE DATABASE testdb;

USE testdb;

CREATE TABLE t1 (
 id INT
) ENCRYPTION='Y';

====================================================
STEP 24 — RESTORE DUMP
====================================================

mysql -uroot -p < /backup/full_no_encrypt.sql

====================================================
STEP 25 — VERIFY DATABASES
====================================================

SHOW DATABASES;

SELECT user,host FROM mysql.user;

====================================================
STEP 26 — OPTIONAL RE-ENABLE ENCRYPTION LATER
====================================================

ALTER TABLE table_name ENCRYPTION='Y';

====================================================
IMPORTANT NOTES
====================================================

1. NEVER DELETE:
   /data/mysql-keyring

2. NEVER MIX:
   old plugin + new component

3. DO NOT USE:
   early-plugin-load=keyring_file.so

4. NEW MYSQL 8.4 USES:
   component_keyring_file

5. MOST IMPORTANT FILE:
   /usr/sbin/mysqld.my

WITHOUT IT:
- component installs
- but encryption fails

6. IF RESTORE FAILS:
- use ENCRYPTION='N'
- restore first
- re-enable later

###############################
END
###############################