Kubernetes secrets are objects that provide access to and manage sensitive data, allowing workloads and services to authenticate with each other and unlock resources protected by access controls. They help avoid embedding sensitive data directly into configuration files or commands, which would be insecure. Secrets can store any type of data defined by users, including authentication secrets, service account tokens, encryption secrets, SSH credentials, and opaque secrets. Kubernetes secrets use cases include supporting logins and data encryption for cloud-native applications and managing interactions within the cluster using service accounts. Creating secrets in Kubernetes involves using kubectl to generate or reference a file containing secret values. Once created, secrets can be used by injecting them into workloads as environment variables or mounting them as data volumes. However, Kubernetes secrets have limitations, including lack of encryption, challenges with secret rotation, misconfiguration risks, limited integration with external systems, lack of scalability, and limited auditing. External secrets managers like HashiCorp Vault or AWS Secrets Manager can address these limitations by providing stronger security, comprehensive secrets management, enhanced scalability, and improved auditing capabilities. Best practices for managing Kubernetes secrets include encrypting secrets, using short-lived secrets, auditing RBAC configurations, implementing secrets rotation, avoiding hard-coded credentials, limiting secrets access to specific containers, and securing secret data after access.