--- created: 2021-10-20 aliases: --- ## Definition A lock-step deploy is when you have 2 or more services that are deployed at the same time, in the same [[CICD|CI/CD]] setup. It could be a web app and a backend API. It could be two backend API's. It could be a backend API and a running background job doing some processing talking to the API. The exact shape of the services is less important. What they _do_ is less important too. The important thing (the problem) is that they **are** deployed at the same time. They are kinda wired together, as the below picture illustrates. It's hard to update one without affecting the others. [^fn1] [^fn1]: [Problems with lock-step deployment](https://blog.steadycoding.com/problems-with-lock-step-deployment/) by Jim Aho