Nothing is perfect. And a canary deployment is not the exception. Let’s see the flip side of canary deployments.

Frustration: the first group using the canary will find the worst bugs. What is more, some users may be put off to learn they were used as guinea pigs. If you’re worried about this, consider starting an opt-in program (call it something like “early adopter” or “insider program” for added coolness).

Costs: side-by-side deployments cost is higher because we need extra infrastructure. Use the cloud to your advantage; create and remove resources on demand to keep the costs down.

Complexity: canary deployments share the same complexities as blue-green deployments. Having many production machines, migrating users, and monitoring the new system; these are complicated tasks. Avoid at all costs doing them by hand. Always automate the deployment process using a CI/CD platform like Semaphore.

Time: setting up a healthy canary deployment pipeline takes time and effort. On the plus side, once we get it right we can do more frequent and safer deployments.

Databases: entire books have been written on how to make database schema changes. The problem is the database must simultaneously work with the canary and the control versions during the deployment. So, if we have breaking schema changes, we’re in trouble. We need to maintain backward compatibility as we make changes, which adds another layer of comp

https://www.squadcast.com/blog/what-are-canary-deployments-and-why-are-they-important#:~:text=Disadvantages%20of%20canary%20deployments,may%20call%20for%20further%20research.