Mule 4 Migration: Blueprint for Success
If you’ve been following along with our previous articles focused on migrating from Mule 3 to Mule 4, you’re already well aware that this change is less of a simple upgrade and more of an evolution. As that implies, the work to move to Mule 4 is more intensive, requiring planning and the application of best practices to achieve a clean migration.
What’s left? The final step is putting together a pragmatic map to get you from your current Mule 3 implementation to taking advantage of everything Mule 4 offers. This piece will give you the blueprint you need for a successful migration, with the flexibility to add to your MuleSoft implementation's specific requirements. We’ll even share some of the key inflection points that we use when Big Compass has helped other businesses get their migrations done efficiently and effectively.
Step 1: Create Your Migration Team
Since the move to Mule 4 is essentially a re-platforming rather than a simple upgrade, it’s important to treat it with that level of importance. That means approaching the upgrade like a full-blown project. Setting the expectation that this isn’t a skunkworks project, but a real initiative will put you in the mindset of assigning resources and developing sprints or timelines, as appropriate.
If you haven’t already planned it this way, you should attach resources like developers, infrastructure, and operations team members, to the project. Each of these groups will have a role to play.
- Developers: If they haven’t already been trained on Mule 4, now is the time to level up.
- Infrastructure: Environments may need to be spun up and others decommissioned.
- Network Operations: Some of this project is likely to involve re-assigning ports and handling firewall requests.
The business also needs to be kept informed of the project. At some point, there will likely be a production cutover that might impact business users. A communication plan should be part of your planning and timeline.
Of course, convincing those stakeholders responsible for budgets and financials may be a challenge. Explaining that you’ll need time and talent to do a migration that leaves you in the same place, just on better, newer technology, can be challenging. If you need to build a business case, be sure to include the benefits of Mule 4, such as the new features and community support and the risk, as Mule 3 will ultimately no longer be supported.
Step 2: Review Your Mule 3 Applications for Migration or Retiring
Knowing what to add into your project plan for the migration requires understanding what will be done with each application - will they be migrated, reworked, or retired?
Understanding the value provided by your applications requires data, and in many instances, it is best accomplished with a fresh set of eyes. Looking at app usage can be a good starting point and quickly weed out those Mule 3 applications with low or no usage. An API usage dashboard, like the one Big Compass has developed, can offer a lot of information and can also indicate which applications will be the most crucial in the migration plan.
Your application list needs to be inclusive, covering the impacts and changes of migrating or retiring these Mule 3 apps. This is an ideal point to inject outside resources for review and recommendations. Big Compass can offer an informed and unbiased look through several lenses, including:
- Tech Debt
- And other critical views.
Plus, with deep Mule 4 experience, Big Compass can help direct which application(s) can be easily converted from Mule 3 and which ones require more time to make intelligent migration/rework/retirement decisions.
Step 3: Review the New Mule 4 Features to Use for Migration
Next, you’ll want to review the new features that are part of Mule 4 to determine if you will use them as part of your migration. As mentioned in the other pieces in this series, MuleSoft has published several resources to help you understand what is different between Mule 3 and Mule 4.
A few areas that you’ll want to pay special attention to include:
- Performance improvements: Meet your SLAs better and more consistently,
- High-volume apps and ability to scale: Changes in Mule 4 include improvements to batching,
- CI/CD: Mule 4 has native support for CI/CD enablement, enabling you to improve your CI/CD implementations for your Mule applications.
Step 4: Create an Application Migration Order
Unless you have a small number of apps to migrate, you simply cannot migrate them all at once. You’ll need an order of migration to see the project through.
Start by creating groupings of APIs. APIs common at the domain level - like those that serve HRIS and employee functions or those tied to customer operations - are one set of groupings. Common business functions can be considered together. So can those that have infrastructure elements in common. These groupings will begin to paint a picture of your migration order.
This will also call out those applications that don’t need to be migrated or those that don’t fit into another box. You’ll need to consider where these fit into the order, as well.
Together, your path and plan will evolve from this information. Using MuleSoft’s API-led philosophy, you can start to create your actual plan.
Step 5: Contact Your MuleSoft Account Manager
This may seem like a strange item for your plan, but in reality, it’s as essential as every other step in your migration. Contact your MuleSoft Account Manager and discuss your MuleSoft 4 plans.
Few companies can do a complete one-and-done cut over from Mule 3 to Mule 4. Fewer even want to do so. If you have many applications that will need to be updated and moved, cutting everything over at once could end up a support nightmare.
Instead, you’ll likely take an iterative and measured approach, moving some APIs, allowing time for critical testing integrations, and so on. Your MuleSoft Account Manager will help you keep your licensing compliant while keeping costs under control.
Some questions you’ll need to answer with your account manager include:
- Do you need additional capacity?
- Do you have the right licenses for multiple environments?
- How long will you need different licenses?
Communicating your plan and how you’ll be conducting the migration will minimize surprises for you and your Account Manager.
Step 6: Migrate Your Applications from Mule 3 to Mule 4
Your migration is now “shovel ready.” At this point, you have two options. You can follow your existing SDLC to get the work done. Or, you can take this opportunity to improve your processes.
Mule 4 has improved support for CI/CD. It uses common tools like Maven and has embedded support for various Git-based repository hosting services (e.g., GitHub, Bitbucket, Azure DevOps, etc.). So the migration might be the ideal time to adopt a more streamlined and modern approach to development and deployment. If you need assistance in implementing or improving your DevOps processes, Big Compass has expertise in combining Mule 4 migrations with CI/CD enhancements.
During your actual migration implementation process, don’t forget to familiarize yourself with the Mule Migration Assistant (MMA). While the MMA might not apply to every migration, it is worth investigating.
Step 7: Retire Your Mule 3 Infrastructure
The last step in your plan is to retire your Mule 3 architecture once everything is cutover. When you do this will largely depend on the impact of that action, the timeframe needed to retire the infrastructure and the migration team's comfort level. Even if you’re doing a single cutover event, it’s a good idea to maintain your Mule 3 infrastructure for a defined time to enable a rollback. Ensure your backup plan is in place, and you’re in an excellent position to do a rollback if needed.
This blueprint increases your chances of success with your Mule 3 to Mule 4 migration. Using it will lessen your downtime, minimize the migration risk, and set you up for a seamless transition. If you’re struggling with how to move forward, or you’re looking for help at any stage of your plan, reach out to Big Compass. We have extensive experience with Mule 4 migrations and can help you determine what needs to be done - and what doesn’t - to keep your Mule implementation working well and take advantage of what Mule 4 has to offer.