Use the moment to replace ubuntu-server with Debian and you'll be glad you did when Canonical decides on its next move to ensnare users. Even when I used Ubuntu - back in the early brown-desktop days when they sent out free CD-ROMs to anyone who wanted one - I never felt tempted to use it on a server since it was never clear to me what it offered that Debian could not deliver while it was clear that keeping Debian up to date was (and is) far easier than doing the same with Ubuntu.

Ubuntu had its place in popularising Linux but they jumped the shark a long time ago, now they are just another player jostling for their own niche.