Oracle RAC and DataGuard configuration

We have deployed an Oracle RAC cluster which consists of three Oracle instances. As we are considering the HA issue, and as far as I know, the only way of Oracle HA is DataGuard. So is it possible that we deploy DataGuard in another data center as backup for the master RAC cluster and if master RAC cluster down, We can switch the DataGuard to master which enable read and write operations. Someone told me that it is a very complicated process. Is that true? how much time does this process cost? Is there any other solutions on Oracle HA or any other load balance solution to replace RAC cluster? Does Mysql have the same capability?