Glimpse of Google: Post mortems

Welcome to Glimpse of Google, a blog series written by a former Google software engineer, offering a firsthand look into the inner workings of one of the most transformative companies of our time. This series will uncover how Google operates from an engineering standpoint and explore the broader company culture, guiding principles, and unique approaches that make it a powerhouse in technology. Whether you're an engineer, a tech enthusiast, or simply curious, Glimpse of Google provides insider insights into what makes Google tick.

A postmortem is much more than an exercise in documenting failure. It's a powerful tool that embodies the core principles of their blameless culture and the relentless pursuit of improvement. These aren't simply documents gathering dust in a digital archive – they become actionable blueprints for building more resilient systems. Let's dive deeper into the nuances of the postmortem process:

When something goes wrong in production, be it a full-blown service outage or a less impactful glitch, a blame-finding witch hunt is the last thing on anyone's mind. The engineer most closely involved in the incident – whether they accidentally deployed a faulty code change or heroically led the charge to restore service – takes the lead in crafting a detailed postmortem document. Freed from the fear of punishment, they can delve into a transparent, chronological breakdown of what happened. This includes the obvious symptoms (error messages, user-facing impact) and the more technical chain of events that led to the problem, along with detailed steps taken to resolve the situation.

But Google's postmortems don't fixate on the "who" or the "what" – they obsess over the "why." This is where the root cause analysis shines. Was it a single errant line of code, or did the issue expose deeper flaws in the system's design? Did a third-party dependency prove unreliable? The engineer, along with other team members, carefully dissect the factors that allowed this failure to manifest. The ultimate goal is to identify patterns and weaknesses that can become targets for improvement. This leads to the most impactful part of the postmortem: the concrete action items.

These aren't simple band-aid solutions. They could involve substantial code changes, implementing new safeguards and automated tests, beefing up monitoring and alerting systems, or even rethinking entire architectural components. These action items aren't filed away and forgotten – they are tackled with utmost seriousness. Management understands that neglecting them only leaves the door open to future failures and erodes user trust. In an environment focused on long-term gains, it's imperative to address the issues identified during a postmortem and make those system improvements a top priority.

The postmortem becomes a catalyst for collaboration. It's rarely a solitary task. The engineer who wrote the initial draft benefits from input from teammates, senior engineers, and even experts from other teams with specialized knowledge about a particular component. This open dialogue ensures that blind spots are caught, potential consequences are explored, and the resulting solutions are comprehensive and effective. In a blameless environment, postmortems foster a sense of shared responsibility. Engineers don't operate in fear, knowing that honesty and transparency are what will make their systems stronger. By pooling their collective wisdom and experiences, they can develop strategies to not just withstand failures but emerge from them more robust than ever before.

At Google, a postmortem serves as a testament to the company's commitment to delivering an exceptional user experience. It's an acknowledgment that things will inevitably go wrong, but those missteps don't have to signify enduring defeat. They are turned into opportunities for meticulous growth, ensuring that the systems supporting their products become stronger, smarter, and more reliable with each passing challenge.