Establish and Document the Application's Tear-down (De-installation) Procedures

This chapter explains how to establish and document the procedures for removing an installed version of an Application, or an entire Application Instance, from an environment.

Definition

Tear-down (De-installation) is the de-installation of an installed version of an Application, or of an entire Application Instance, from an IT Operating Environment Instance, performed to make way for the installation of a newer version, or to complete the removal of a Decommissioned Instance. The Application continues to exist unless it is being Fully Retired.

Why Tear-down Must Be Documented

Tear-down is a routine operation, not only an end-of-life one. Many Deployments begin by tearing down the previous version, and test environments are frequently torn down and rebuilt. Yet Tear-down is often poorly understood, and incomplete removals leave behind files, services, scheduled jobs, accounts, network rules, certificates, and data that pile up as clutter, cost, and security exposure. A documented Tear-down procedure ensures that removal is complete and safe.

Establish the Tear-down Procedures

Establish, with the IT Application Owner and the Operations and Support Team(s):

• What must be removed to de-install a version, and what must be preserved, such as data and configuration needed by the next version.

• What must be removed to tear down an entire Instance, including compute resources, storage, scheduled jobs, service accounts, network and firewall rules, certificates, monitoring, and entries in other Systems that refer to the Instance.

• How data is handled during Tear-down: retained, archived, migrated, or securely disposed of, according to the Application’s retention rules.

• How to verify that Tear-down is complete.

• Who must approve tearing down an Instance, especially a Production or Decommissioned Instance.

Document and Share the Tear-down Procedures

Record the Tear-down procedures in the Release and Deployment and Operational sections of the Application Documentation, with Instance differences recorded explicitly. Record each Instance Tear-down, its date, its approver, and the verification of its completion, and update the Application’s list of Instances accordingly.

Best Practice: Establish and Document the Application’s Tear-down Procedures

It is a best practice to both establish and document the solution for removing an Application’s versions and Instances: define what must be removed and preserved, how data is handled, how completeness is verified, and who approves, and record every Instance Tear-down.

Benefits: Documented Tear-down leaves environments clean, preventing the forgotten services, accounts, and data that accumulate cost and security exposure. Recording each Tear-down keeps the Application’s list of Instances accurate, so that no one wastes time investigating, or patching, an Instance that no longer exists.

Connections to Related IF4IT Practices and Inventories

The IT Operating Environments Best Practices addresses decommissioning environments deliberately so they do not persist and accumulate cost, configuration drift, and risk.