Let's switchover es1023 to es1024 which is already running Buster and Mariadb 10.4.
We cannot put es5 in RO from MW, so we need to do it directly at MySQL level.
My proposal is to use the switchover script using:
```
./switchover.py --skip-slave-move --read-only-master es1023 es1024
```
So steps (simplified):
Switchover day:
```
- switchover.py --timeout=15 --only-slave-move es1023.eqiad.wmnet es1024.eqiad.wmnet
- Disable puppet @es1024 and @es1023
- Merge puppet change to promote es1024 to master
- !log Starting es5 failover from es1023 es1024
- es1023: set global read_only=ON;
- ./switchover.py --skip-slave-move --read-only-master es1023 es1024
- es1024: set global read_only=OFF;
- Enable and run puppet at es1023 and es1024
- events_coredb_master.sql on the new master db1086
- events_coredb_slave.sql on the new slave db1062
- Change es5-master DNS
```
@jcrespo I would appreciate a review of the above simplified steps
Pending: Decide a day&time