Description: The StatefulSet update strategy in Kubernetes defines how updates to StatefulSets are managed, which are a type of resource designed to manage stateful applications. Unlike Deployments, which focus on stateless applications, StatefulSets provide specific features that allow maintaining the identity and state of applications throughout their lifecycle. This includes stable name assignment, persistent storage, and management of the deployment and update order of instances. The update strategy can be either ‘RollingUpdate’ or ‘OnDelete’. In ‘RollingUpdate’ mode, updates are performed gradually, allowing instances to be updated one at a time, ensuring that a minimum number of pods are operational at all times. On the other hand, in ‘OnDelete’ mode, pods are only updated when manually deleted, which can be useful in situations where stricter control over the update process is required. This strategy is crucial for applications that require high availability and consistency, such as databases and messaging systems, where data loss or service interruption can have significant consequences.
