Calico stores the data about the operational and configuration state of your cluster in a central datastore. If the datastore is unavailable your Calico network continues operating, but cannot be updated (no new pods can be networked, no policy changes can be applied, etc.).

Calico has two datastore drivers you can choose from

• etcd - for direct connection to an etcd cluster
• Kubernetes - for connection to a Kubernetes API server

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We are currently using etcd datastore, but that was the only available datastore in the past. So we might want to revisit the "decision" as we now have the chance to do so easily.