The shop I just moved to has the usual roll-your-own mess, but the shop I just left did it right: "yum update". Making RPMs isn't hard, and it ensures appropriate versions of all dependencies are there (even stuff like syslog-ng configs), and their tiny overworked sysadmin team didn't have to know or care which language they're implemented in, or whether there's anything smuggled onto each box behind their backs, or how to bring a freshly-imaged box into production. They ran a small script to fake a health check failure on a few servers at a time to do it without load, because they didn't want to reserve the footprint to run two versions of an app server in parallel on each box.