Back to resources

Migrating a Legacy Service: A Lesson in Eng/Ops Collaboration

Collaboration

18 November, 2020

Jackson Dowell
Jackson Dowell

Engineering Manager at Asana

Jackson Dowell, Engineering Manager at Asana, discusses how he approached legacy service migration by stabilizing the existing stack and getting Engineering and Operations to work together to address the underlying problems.

Problem

I was managing a team at LinkedIn that inherited a set of legacy Python services that we were part-way to migrating to a new Java microservices stack. In the past, Engineering was focused on building the new stack and running the data migration while Operations was siloed and responsible for keeping the existing software alive - including some wild hacks and constant pages. Ultimately the existing Python services were causing regular production outages and the migration plan failed to address the underlying technical issues, so I needed to reprioritize and change how engineering and operations were working together.

Actions taken

Our NYC-based team flew to California to do a handoff with the existing development team because the project was in flight. I had my engineers pair with the team that was actively working on the migration, taking small tasks across both systems and getting mentorship so we could learn how to confidently make and release changes.

As part of the handoff, I facilitated meetings between SRE (Site Reliability Engineer) leads who were transferring ownership of this project. Participating in their exchange helped me compile the full state of the world of the software that was operating in production, including the existence of a script that rebooted hosts stuck on failing jobs that executed at least once a minute across the whole fleet.

During the first week we took over, there were two outages caused by that piece of software. In the first instance, I had a member of my team pair directly with the engineer who investigated and resolved the incident. In the second case, the engineer on my team was able to take the lead and, supported by another person on the team, resolve the problem. I noted commonalities between both incidents and action items we would take to prevent the problem from recurring.

Once I had a full understanding of the existing system and the migration plan, I wrote up an analysis that I shared with my manager and the team of leads in New York to secure buy-in for a process called code yellow -- active feature development would pause until the operations were stabilized to the point that both SRE and Engineering were satisfied. I defined the exit criteria for code yellow, which included completing action items from the past incidents, introducing connection pooling and connection limits to the database (preventing cascading failures), and introducing a paging rotation in engineering to support future outages. We targeted a two-week window and were able to exit code yellow on time.

Lastly, I worked with my Tech Lead to revamp the migration plan to address failures in long-running jobs in the first milestone and to improve the safety of the data migration. We communicated the new plan. then held daily standups where engineers and SREs worked together to balance addressing short-term stability issues and investing in the migration to get to a long-term safe and scalable state.

Lessons learned

  • Having Engineering and Operations both take responsibility for solving incidents (including being paged) instilled a culture of caring for the reliability of our software. The engineering team translated that into excitement for discovering and remediating existing bugs and producing high-quality designs for the new system. The SRE team also felt supported and collaborated regularly to define requirements for how the new system would behave and solve current problems.
  • I got positive reinforcement for questioning the existing plan given new information. Even though it was controversial to delay our migration, we were ultimately able to provide better service to our customers and members, and we learned a lot about how to design our system to scale effectively.

Discover Plato

Scale your coaching effort for your engineering and product teams
Develop yourself to become a stronger engineering / product leader


Related stories

The Importance of Culture and Values When Building Teams

26 May

Elwin Lau, Director of Software at Jana, advocates the importance of maintaining culture within a company when scaling teams.

Mission / Vision / Charter
Scaling Team
Building A Team
Company Culture
Collaboration
Onboarding
Sharing The Vision
Elwin Lau

Elwin Lau

Director of Software at JANA Corporation

Managing Different Time Zones: Inclusive Collaboration Methods

19 May

Jonathan Belcher, Engineering Manager at Curative, shares an unknown side of synchronous communication tools and advises managers on how to handle a team that’s spread across the globe.

Remote
Internal Communication
Collaboration
Cross-Functional Collaboration
Jonathan Belcher

Jonathan Belcher

Engineering Manager - Patient Experience at Curative

Creating a Company Culture That Balances Helpfulness and Productivity

16 May

Alexis Philippe, Vice President, Product & Engineering at Amilla, describes his one simple rule for creating a culture of helpfulness that doesn't disrupt productivity.

Mission / Vision / Charter
Company Culture
Collaboration
Cross-Functional Collaboration
Alexis Philippe

Alexis Philippe

Vice President, Product & Engineering at Amilla

Streamlining Product Processes After a Reorganization

16 May

Snehal Shaha, Lead Technical Program Manager at Momentive (fka SurveyMonkey), details her short-term technical strategy to unify processes among teams following an acquisition.

Acquisition / Integration
Product Team
Product
Building A Team
Leadership
Internal Communication
Collaboration
Reorganization
Strategy
Team Processes
Cross-Functional Collaboration
Snehal Shaha

Snehal Shaha

Senior EPM/TPM at Apple Inc.

How Less Viable Solutions Solve Common Architectural Challenges

13 May

Tom Hill, Engineering Manager at Globality, Inc., describes his decision-making practices when making architectural decisions.

Architecture
Different Skillsets
Conflict Solving
Collaboration
Tom Hill

Tom Hill

Engineering Manager at Torii

You're a great engineer.
Become a great engineering leader.

Plato (platohq.com) is the world's biggest mentorship platform for engineering managers & product managers. We've curated a community of mentors who are the tech industry's best engineering & product leaders from companies like Facebook, Lyft, Slack, Airbnb, Gusto, and more.