A VMM in state 'starting' can receive requests#7398
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If a VMM is in state 'starting' and cannot activate a given disk, it will hang. Region replacement or region snapshot replacement may alter the VCR of that disk to one that *could* be activated, but the current drive saga will not attempt to send requests to a VMM in 'starting'. Fix this - any time a Propolis is expected to be there, it should be ok to receive these requests. Otherwise a repair can be stuck, and the VMM could fail to stop if it gets stuck deactivating too!
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Have we verified empirically that region snapshot/replacement work as intended on a Propolis that hasn't yet reached Running? I'm not certain they will (and would need to go look carefully at the relevant Propolis code to check). |
hawkw
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I agree with @gjcolombo --- it's worth making sure that propolis-server can actually handle region replacement requests in that state.
| | VmmState::Rebooting | ||
| | VmmState::Starting => { | ||
| // Propolis server is expected to be there | ||
| // (eventually, in the case of "Starting"), and |
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I believe that a VMM isn't in the Starting state unless the Propolis server process does exist, FWIW --- if memory serves, that's the distinction between Starting and Creating. It may not yet be incarnating an instance, though.
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I looked at this a bit. In Propolis there are at least two things we need to consider:
It might be possible to fix the latter issue, but it's probably going to take a fair amount of effort on the Propolis side of the house. (We'd also need to be sure that if we have a Crucible upstairs that's stuck in a |
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Filed oxidecomputer/propolis#841 to track the relevant Propolis enhancement. |
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@askfongjojo I believe this issue was resolved by @gjcolombo's work in oxidecomputer/propolis#873 --- right, Greg? |
Oh, whoops, this is a PR, not an issue. I'll take a look. |
hawkw
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Okay, I believe that now that @gjcolombo's merged oxidecomputer/propolis#873 and oxidecomputer/propolis#880, a VMM in state 'starting' now actually can receive requests. :)
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@jmpesp is this change still needed? It looks like the merge conflict is just rustfmt churn. As of Greg's work on oxidecomputer/propolis#880, Propolis should be able to handle region-replacement requests when in |
If a VMM is in state 'starting' and cannot activate a given disk, it will hang. Region replacement or region snapshot replacement may alter the VCR of that disk to one that could be activated, but the current drive saga will not attempt to send requests to a VMM in 'starting'. Fix this - any time a Propolis is expected to be there, it should be ok to receive these requests. Otherwise a repair can be stuck, and the VMM could fail to stop if it gets stuck deactivating too!