What are the most important considerations when decommissioning a system?

Plan as below - What has to be EOL'ed - List dependencies -- Hardware -- Software -- Users -- Upstream and Downstream apps - Communicate -- Be ready for surprises - Plan for migration if some software's are in use and hardware has to be EOL'ed - Backup data. - Remove top secret / confidential data if any as per policy. - Once all users / apps are migrated to new systems, shutdown and do a scream test - Once scream test is pass, remove systems from environment with data wipe. - Remove firewall rules if any - Clear DNS entries

Also, Monitoring is vital during system decommissioning as it helps to identify dependencies to prevent unexpected failures. Monitoring tools must be cleansed of orphan entities after decommissioning.

Simplicity is the key when decommissioning a service. The goal is to do it quickly and securely, without unnecessary bureaucracy. The burden of filling out documents, creating multiple tickets, seeking authorization, and completing the task can be a headache. Automated processes can help streamline the decommissioning process, reduce stress, and save time, all while ensuring compliance.

Every detail needs to be thoroughly communicated with stakeholders. Necessary details like downtime also should be explained to clients and partners. The reason for the decommisioning must be backed by data and all maintenance window must be as per the agreed upon SLA for the system and/or services associated with it.

Effective communication is crucial when decommissioning a server or service. How many times do we discover that a critical resource is no longer available because it was decommissioned without warning? The owners of the systems must approve the change and be consulted throughout the decommissioning process. Implement a robust communication and alerting strategy to ensure that the Configuration Management Database (CMDB) is accurately updated and that monitoring systems reflect the changes.

In my experience, communication is a often overlooked component. Communicate as much as is possible and have an issue management plan, to address any spill overs.

Integration tests play a crucial role in assessing whether the absence of a service will affect the overall structure of your system. It's vital to have a deep understanding of dependencies to make informed decisions. Avoid making assumptions and rely on concrete data and testing to guide your judgment.

When wiping assets, take an engineer’s approach of rigorously verifying successful decommissioning. Implement robust validations using canaries and dark launches to minimize disruption. Monitor system-wide impacts on interconnected services. Evaluate potential degradation from the user’s viewpoint. Architect resilient fallback mechanisms to limit downtime. Approach this as an optimization challenge - utilize experiments and data to refine migrations. Collaborate cross-functionally to capture diverse feedback. Smooth decommissioning enables velocity. With care and discipline, we can upgrade infrastructure, securely retiring legacy systems while protecting productivity and user experience.

By thoroughly documenting and reviewing the lessons from the decommissioning, organizations can foster continuous improvement. This not only ensures that future decommissions are executed efficiently but also helps in maintaining a knowledge base that can be invaluable for other IT projects. ✅Identify Gaps ✅Highlight Successes ✅Compile Feedback ✅Update documentation ✅Checklists decommissions. ✅Training Material

Decommissioning is not as simple as shutting down and forgetting about it. It involves updating various systems, including monitoring, patch management, and tracking dependencies, among other tasks. We are always striving for improvement. This involves documenting the process, creating checklists, and ultimately establishing an automated workflow. This process is implemented through interactive steps.

Maintaining a system inventory is no easy task. Your tool should handle this automatically. If you're still doing it manually, things can quickly get off track. Ensure there's an automated check-in and checkout process in place.

In my experience, decommission in general is intiated by IT. Because in it's intiation, it misses business owner input, especially hardware (servers); the process runs smoothly through change management. But in the end, hardware remains redundant (unused, stored in dust) without fully auctioned off or destroyed. We may need to add Business at the beginning of the process to determine the final resting place of these beautiful 'servers'.

In my experience of recent decommissioning of systems/solutions a good communication plan to your internal customers is essential. Make sure everyone understands what is happening, why and when. What do they need to do and by when. We have used a 3 x 30 days approach to make sure but you could easily cut this down if your comfortable to. 1st 30 days - Communicate that you are decommissioning all the services and share with the effected people and tell them what they need to do. 2nd 30 days - Close down the servers or solution and wait to make sure there is nothing business critical effected 3rd 30 days - As long as you had no issues in the last 60 days start the actual process to remove the servers or solution. Communicate your success.