Feature/limit disk io

[atta]

Allow to control the amount of I/O that a Instance can perform

[googlebot]

So there's good news and bad news.

👍 The good news is that everyone that needs to sign a CLA (the pull request submitter and all commit authors) have done so. Everything is all good there.

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[iustin]

So, without looking at the code itself - adding a new feature doesn't seem like the proper thing to do on a stable branch. Would you mind sending this against master instead?

[googlebot]

CLAs look good, thanks!

[atta]

since we wait so long to get 2.16 released we had to start to move things forward and add features to 2.16 we needed.

i'am fine with adding the feature to 2.17 but please keep ganeti going

[saschalucas]

@atta, would you be so kind to PR against master, so that we can merge it for 3.1? The code looks good to me. Spelling and wording in the man page can be improved.

[rbott]

LGTM and has passed the QA suite (although there are no specific tests for it of course - but it also does not break anything unrelated).

[rbott]

This should be rebased on the current master once #1667 has been merged. It will remove the -drive parameter and hence render this patch unusable. From the QMP Reference Docs it looks like you need to add a "throttle filter driver" in between the blockdev and the disk driver.

Please also be aware that this needs to be done for regular instance start (_GenerateKVMBlockDevicesOptions() in hv_kvm/__init__.py) and also for disk hotplugging (HotAddDisk() in hv_kvm/monitor.py).

The new parameters also need to be added/removed to the config data during up/downgrade.

[atta]

thanks will have a look