Which characteristic is shared by Ansible and Chef?

Both Ansible and Chef are configuration management tools primarily designed for managing mutable infrastructure. Mutable infrastructure means that servers and other network devices are updated, patched, and reconfigured in place over time. While both tools can be adapted for immutable infrastructure practices, their core design supports modifying existing systems. The statement that both rely on a declarative approach is incorrect; Chef is primarily declarative, but Ansible can be both imperative and declarative. The statement that both require a client to be installed on hosts is incorrect; Chef requires a client (agent), but Ansible is agentless, using SSH for communication. The statement that both rely on NETCONF is incorrect; NETCONF is a protocol for managing network devices, not a core communication mechanism for either Ansible or Chef in their general use cases.