Container environments change frequently.
Sometimes developers update the code that's running within the container, an application inside, or sometimes they push different components in the container. Other times, containers will be affected because of the need to scale — like when applications spawn off more of the same container to handle capacity when running at its peak.
The constant rate of change makes it difficult to manage containers. And without sufficient visibility into what's going on, you risk serious security implications. For example, when a container becomes "stale," and the base image, components or code isn't kept up to date with security and functional patches.
New security vulnerabilities and exploits are discovered every day. This is why tracking containers manually is not a sound option. The solution is container automation. But if you're new to the idea, just know that container automation is not as simple as flipping on a switch.
One mistake you can make with container automation is to go big at the onset, so start small. Pick a single workload and work your way through that first. Make sure you understand how the automation tools work in the initial environment before you begin about expanding.
When implemented correctly, automation lets you effectively monitor your containers. The tools watch your environment, assess the status of your containers, look for problems, let you know when you need to upgrade and more.
Without automation, you're going to struggle to keep up with the rapid rate of change within your containers. And if it's anything like a fridge overflowing with containers of leftovers, you don't want that mess on your hands.