Blue-green deployments can help you minimize both the downtime and the risk related to deploying your app. To do so, you'll need two identical production environments, called blue and green. While green serves the customers, you can perform the update in the blue one. Once the update was made, the services were tested, and all looks stable, you can switch the traffic so it now flows to the updated (blue) environment.
If any issues are spotted in the blue environment after the switch, the green one is still there – you can just switch them back. The users probably won't even notice any changes, and because both the environments are up and running, no downtime should be visible during the switch. Just make sure you won't lose any data during the switch (for example, transactions made in the new environment).
