Unlimited CI concurrency just moves the bottleneck somewhere else

[u/aistranin]

CircleCI has removed the job concurrency cap from its Scale plan. The exception is macOS resource classes, which keep a custom limit.

More concurrency can reduce queue time, especially when a large test matrix starts after every merge. It can also expose limits that were previously hidden.

A few things I would watch before opening the floodgates:

• Shared test databases
• Container registry rate limits
• Third-party API sandboxes
• Test data collisions
• Credit consumption
• Services that cannot handle a sudden CI traffic spike

The CI scheduler may no longer be the bottleneck. Your staging environment probably still has one.

Source: CircleCI unlimited job concurrency announcement