# The hidden value of containers

It might not be obvious, and certainly when I got started with containers, I didn’t realize that there’s side-benefits that are not typically talked about.

You might know the main benefits already,

*   Similar to VMs, they provide a consistent runtime environment
*   Similar to VMs, they act as a sandbox for applications
*   Unlike VMs, they have a small disk footprint
*   Unlike VMs, they have a very small overhead

In short, because they are lightweight, they have all the benefits from VMs and they are fast to start. This small difference opens a new world of possibilities.

Extending the Art of the Possible
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Since they are fast to start and they are portable, with some work you can run the entire application from the CI/CD pipelines. This opens new possibilities for things that were once much harder to do - running functional tests **before** deploying anywhere.

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1637640034132/WK0hsQ9Ho.png)

In the example above, we run functional smoke tests against a _docker compose_ version of the application, database and all. You can extend this concept to also run penetration tests as I alluded in my previous [DevSecOps post](https://gaunacode.com/a-devsecops-process).

What’s risky? What fails often? Database changes? API Authentication?

There are things you can probably test with containers without deploying to an environment _and_ spending money on cloud resources.