Feature gates are key-value pairs that describe upstream Kubernetes features.
A feature can be in an Alpha, Beta, or General Availability (GA) state.
If the feature is in Alpha, then the feature is disabled by default and may be buggy.
If the feature is in Beta, then the feature is enabled by default and has been well tested.
If a feature is in GA, then the feature is stable and always enabled.
See the Kubernetes documentation to check which feature is in the alpha, beta or general availability stage.
DigitalOcean Kubernetes only supports features that are in a beta and general availability stage in upstream Kubernetes. You cannot modify the feature gates when using DOKS. See The Managed Elements of DigitalOcean Kubernetes for more specifics.