Oracle RAC and DataGuard configuration
(MySQL)

There are several MySQL Replication topologies.  For HA, deploying at least one server in each of 3 datacenters and using Galera Cluster, failover is essentially automatic if a datacenter goes down.  Some form of proxy or load balancer could take care of redirecting users to the still-alive nodes.  When the datacenter comes back up, that node will get back in sync.

If a node crashes and burns, wheel in a new server; the live nodes will pour a copy of the data set into it, and you are back on the air.

And you did not get paged.

(Now perhaps we will hear from users for which it was not that seemless.)

Group Replication is another HA product on top of MySQL.  I have seen 3 nodes being set up during a conference talk.  It took one person less than 5 minutes.

Caveat:  I cannot say whether either of these is easier or harder than Oracle's offering(s).