  The KM3NeT Collaboration runs a multi-site neutrino observatory in the
Mediterranean Sea. Water Cherenkov particle detectors, deep in the sea and far
off the coasts of France and Italy, are already taking data while incremental
construction progresses. Data Acquisition Control software is operating
off-shore detectors as well as testing and qualification stations for their
components. The software, named Control Unit, is highly modular. It can undergo
upgrades and reconfiguration with the acquisition running. Interplay with the
central database of the Collaboration is obtained in a way that allows for data
taking even if Internet links fail. In order to simplify the management of
computing resources in the long term, and to cope with possible hardware
failures of one or more computers, the KM3NeT Control Unit software features a
custom dynamic resource provisioning and failover technology, which is
especially important for ensuring continuity in case of rare transient events
in multi-messenger astronomy. The software architecture relies on ubiquitous
tools and broadly adopted technologies and has been successfully tested on
several operating systems.
