ChangeMan- Install and Backout

Install is the final step of the lifecycle: at the scheduled date and time, ZMF copies the package components into the production libraries. Backout is the safety net: if the change causes production problems, ZMF restores the previous versions from the backup it took during install.

Install types: planned vs unplanned

• Planned permanent - the normal install: scheduled date and time, change stays in production.
• Planned temporary - scheduled install with a removal date; ZMF automatically backs the change out when the removal date arrives. Used for one-off or seasonal changes.
• Unplanned permanent - emergency install with no scheduled date (for example a production fix needed tonight). Raised through the Install panel with the unplanned flag.
• Unplanned temporary - emergency change that is removed later.
• Unplanned installs usually need extra approvals and a documented business reason; auditors review them closely.

Pre-install checks

1. Package is frozen with a clean (RC 0) audit.
2. All required approvals are recorded; no outstanding approvers.
3. The scheduled install date and time has arrived (for planned installs).
4. No install date conflict: another package installing overlapping components at the same time must be reviewed so the two changes do not clash.
5. The ZMF scheduler (started task) is up so the install job actually launches.

The install job

• At install time, the scheduler submits the install batch job for the package.
• The job first copies the current production members into backup datasets - this is what makes backout possible.
• It then copies the package components from staging (or the final promotion level) into the production libraries.
• After a successful install the package status becomes installed, and the new versions become the baseline for future checkouts.
• If the site distributes to remote data centers, the install job handles distribution as well.

A typical package status display at install time:

Approvals revisited

• Approval entities (team lead, QA, DBA, operations) are defined per application in global parameters.
• Approvers grant approval on the Approve panel; ZMF records who approved and when.
• A package with missing approvals simply will not install at its scheduled time - the scheduler skips it.
• If an approver is unavailable, most sites define alternates; check the approver entity definition rather than waiting.

Backout

• Backout restores production libraries to the versions that existed before the package installed, using the backup datasets taken at install time.
• Run backout from the package Backout option when the change causes production failures and a fix cannot be delivered quickly.
• Backout is recorded in package history with date, time and user, keeping the audit trail complete.
• Temporary changes back out automatically at their removal date; permanent changes back out only on demand.
• After backout, the problem still needs a real fix: create a new package with the correction and run the full lifecycle again.