Example pre-upgrade audit & cutover specimen (MySQL 8.0.36 → 8.4.3 LTS)Sample deliverable
Pre-Flight Audit · 25 Checks Run
14 legacy auth accounts and 4 removed my.cnf directives remediated before cutover
Running util.checkForServerUpgrade() against the customer's read replica flagged 14 microservice accounts still using mysql_native_password plus innodb_log_file_size and default_authentication_plugin in my.cnf. We remediated both in staging, verified zero query plan regressions on an 8.4 LTS sidecar, and promoted the replica in 14 seconds.
Startup blockers cleared18 → 0
Write switchover pause14 seconds
1. Read-only MySQL Shell 8.4 LTS compatibility audit & auth check
Bash & SQL · Pre-Upgrade Audit
# Run Oracle's 25+ point pre-upgrade verification against a read replica
mysqlsh readonly_auditor@10.0.1.25:3306 --js -e "
util.checkForServerUpgrade(null, {
targetVersion: '8.4.3',
configPath: '/etc/mysql/my.cnf',
outputFormat: 'JSON'
});
" > /tmp/mysql_84_upgrade_audit.json
-- Audit accounts that must migrate off mysql_native_password before 8.4 LTS
SELECT user, host, plugin, account_locked
FROM mysql.user
WHERE plugin = 'mysql_native_password';2. Sidecar GTID promotion & reverse-replication rollback gate
SQL · Sidecar Promotion & Rollback
-- 1. On 8.0 primary: fence writes and capture final GTID set
SET GLOBAL super_read_only = ON;
SELECT @@GLOBAL.gtid_executed AS final_80_gtid;
-- 2. On 8.4 LTS sidecar: confirm GTID catch-up and promote to Primary
SELECT WAIT_FOR_EXECUTED_GTID_SET('4a92bc11-82ef-11ee-b9d1-0242ac120002:1-19402811', 10);
STOP REPLICA;
SET GLOBAL super_read_only = OFF;
-- 3. On former 8.0 primary: start reverse GTID replication from 8.4 LTS
CHANGE REPLICATION SOURCE TO
SOURCE_HOST = 'mysql84-sidecar.internal',
SOURCE_AUTO_POSITION = 1;
START REPLICA;