As confirmed by this question, Dumbledore knew that the Defense Against the Dark Arts (DADA) position was cursed by Voldemort so that no professor would hold the position for more than one year. That means that when he finally decided to give Snape the job in the sixth book, he would have known that Snape wouldn't last as DADA teacher more than a year.
This seems like a pretty big risk to take given Snape's value to Dumbledore, and that in the past, DADA teachers had ended up in pretty bad shape (one attacked by a herd of centaurs, one locked in a trunk for 9 months, one fired, one lost his memory, one dead).
My question then is: did Dumbledore plan out, in any rough way, how Snape should lose the DADA position? Obviously if you've read the books, the way it worked out was pretty convenient for Dumbledore's overall plan, but did he know that would happen? Did he take any steps to ensure it would work out that way? Or did he just decide it was about time Snape taught DADA, and whatever happens after, "meh"?
I have the feeling this is in the books somewhere and that I'm just missing it.