Details
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Improvement
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Status: Open
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Major
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Resolution: Unresolved
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4.9.0, 4.10.0.0
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None
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Security Level: Public (Anyone can view this level - this is the default.)
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None
Description
If the KVM heartbeat file can't be written to, the host is rebooted, and thus taking down all VMs running on it. The code does try 5x times before the reboot, but the there is not a delay between the retires, so they are 5 simultaneous retries, which doesn't help. Standard SAN storage HA operations or quick network blip could cause this reboot to occur.
Some discussions on the dev mailing list revealed that some people are just commenting out the reboot line in their version of the CloudStack source.
A better option (and a new PR is being issued) would be have it sleep between tries so it isn't 5x almost simultaneous tries. Plus, instead of rebooting, the cloudstack-agent could just be stopped on the host instead. This will cause alerts to be issued and if the host is disconnected long-enough, depending on the HA code in use, VM HA could handle the host failure.
The built-in reboot of the host seemed drastic