The following behavior is observed in Acronis Cyber Infrastructure (ACI) cluster:
1. Alerts "Node is offline" suddenly appear for all nodes in a cluster for a short period of time. During this time, status of the Storage is displayed as 'Unavailable' per WebCP dashboard.
2. Cluster is displayed as 'Healthy' when checking status of the cluster via CLI.
3. No any real interruptions of storage services are noticed while these alerts appear.
4. Cluster version is below 3.5.5-41.
Issue in the product, behavior is optimized in scope of ACI 3.5.5-41 build with implementation of [VSTOR-36967] "Optimize the schedule of periodic tasks to minimize the number of false-positive "Node is offline" alerts".
Update cluster to the latest available version.
As a temporal workaround it is possible to restart the following service on the cluster Management Node:
# systemctl restart vstorage-ui-backend
If the issue still persists right after applied workaround or big amount of such false alerts is observed with ACI 4.x - contact Acronis support for assistance.