Establishing what you have

THE INVENTORY FIRST: architecture, versions, patch level, backups and access. BEFORE CHANGING ANYTHING. "Before changing anything" is the constraint, and it is what makes this a discipline rather than a preliminary. Every change you make on an estate you do not understand is a change whose consequences you cannot predict. ARCHITECTURE IS MODULE 2 LESSON 10'S MAP AND IT IS THE FIRST DAY'S WORK. Hosts, tiers, how many application nodes, what else lives on those hosts, and which environments exist. Ask explicitly about a second application node and a shared file system — Module 2 Lesson 9 — because assuming a single node is how a change reaches half the users. VERSIONS AND PATCH LEVEL NEXT, FOR EVERY LAYER. They decide what is supported, what a patch would require, and whether the test environment matches — Module 16 Lesson 5. BACKUPS ARE THE SECTION WITH THE DECISIVE QUESTION, AND IT…

In this module: Module 18 · Capstone: a system handed over

1. 1The brief
2. 2Establishing what you have
3. 3Making it recoverable
4. 4Making it observable
5. 5The performance complaint
6. 6The handover