If you want to create your own Operator in the future, you can keep the following tips from CoreOS in mind. Given the nature of their application-specific domain, you'll need to keep a few things in mind when managing complex applications. First, you'll have a set of system flow activities that your Operator should be able to perform. This will be actions such as creating a user, creating a database, modifying user permissions and passwords, and deleting users (such as the default user installed when creating many systems).

You'll also need to manage your installation dependencies, which are the items that need to be present and configured for your system to work in the first place. CoreOS also recommends the following principles be followed when creating an Operator:

• Single step to deploy: Make sure your Operator can be initialized and run with a single command that takes no additional work to get running.
• New third-party type: Your Operator should leverage the third-party API types, which users will take advantage of when creating applications that use your software.
• Use the basics: Make sure that your Operator uses the core Kubernetes objects such as ReplicaSets, Services, and StatefulSets, in order to leverage all of the hard work being poured into the open source Kubernetes project.
• Compatible and default working: Make sure you build your Operators so that they exist in harmony with older versions, and design your system so that it still continues to run unaffected if the Operator is stopped or accidentally deleted from your cluster.
• Version: Make sure to facilitate the ability to version instances of your Operator, so cluster administrators don't shy away from updating your software.
• Test: Also, make sure to test your Operator against a destructive force such as a Chaos Monkey! Your Operator should be able to survive the failure of nodes, pods, storage, configuration, and networking outages.