My first post, being a lurker, ex reservist and current CSC member
Here from the CSC website is the requirements
http://www.csc-scc.gc.ca/careers/003001-3002-eng.shtml
Now in reality, while secondary school education is the minimum, the Correctional Officers I see coming in all have post secondary education (community college Law and Security for the most part, some have university)
The reality is secondary school just won't cut it, it's highly competitive
Also, I'm not 100% sure on this, but with the closing of Kingston Pen and Regional Treatment Centre in Ontario, I don't think they are hiring in Ontario Region. Out west you might have a better chance.
And you don't get paid while on training, although you don't have to pay to be trained
Good Luck
Tom