Storage dependency: cnodes require writeback cache or SSD (2026-08-06)
The k8s control-plane VMs (cnode1/2/3) depend on fast disk fsync for etcd stability. Current storage is qcow2-on-NFS-on-spinning-HDD. Disk cache MUST be writeback or the cluster will crash-loop. See Storage Architecture advisory for full details.
Status: Writeback cache applied to all 3 cnodes. Cluster boots but etcd heartbeat tuning may be needed for full stability. SSD migration recommended for production reliability.
Refs: Redmine [#391], [#367]