4.5. Soft-Fencing Hosts
- On the first network failure, the status of the host changes to "connecting".
- The Manager then makes three attempts to ask VDSM for its status, or it waits for an interval determined by the load on the host. The formula for determining the length of the interval is configured by the configuration values TimeoutToResetVdsInSeconds (the default is 60 seconds) + [DelayResetPerVmInSeconds (the default is 0.5 seconds)]*(the count of running virtual machines on host) + [DelayResetForSpmInSeconds (the default is 20 seconds)] * 1 (if host runs as SPM) or 0 (if the host does not run as SPM). To give VDSM the maximum amount of time to respond, the Manager chooses the longer of the two options mentioned above (three attempts to retrieve the status of VDSM or the interval determined by the above formula).
- If the host does not respond when that interval has elapsed,
vdsm restartis executed via SSH.
vdsm restartdoes not succeed in re-establishing the connection between the host and the Manager, the status of the host changes to
Non Responsiveand, if power management is configured, fencing is handed off to the external fencing agent.