Agent always detect node IOPS to 0

[mildred]

When starting a nomad agent on a node, it detects the available IOPS on that node to 0. it doesn't seem there is a way to override that.

Either you should allow the nomad agent to override the detected IOPS available (you kave a -network-speed option to override the network speed) and document it, or you should remove the IOPS information from the documentation.

[jippi]

It's a documentation issue.. IOPS can be configured inside the client{} stanza on the nomad client (see the source)

Simply add iops = 9999 to force it

Afaik nomad does no effort to detect the iops for a device, as there are no reliable way to do so. AWS could potentially be detected iops for based on the EBS volume, but probably not worth the effort

[mildred]

Isn't the location you linked in the source code a configuration option about reserved resources ? https://www.nomadproject.io/docs/agent/configuration/client.html#reserved

reserved (Reserved: nil) - Specifies that Nomad should reserve a portion of the node's resources from receiving tasks. This can be used to target a certain capacity usage for the node. For example, 20% of the node's CPU could be reserved to target a CPU utilization of 80%.

[jippi]

You are right @mildred - sorry :)

[schmichael]

Right now specifying IOPS in a job only affects exec jobs. For those it is used to directly set the blkio.weight cgroup: https://www.kernel.org/doc/Documentation/cgroup-v1/blkio-controller.txt

That cgroup only accepts a weight from 10-1000, so there's nothing to detect or set for the client.

It should become a more portable IOP provisioning system in the future, but it's use is limited today. Sorry for the confusion! Our docs definitely don't explain it correctly!

[schmichael]

Oops, but I neglected to notice that the scheduler treats IOPS as an absolute resource. So your bug is valid, and there's more to it than I originally suspected! Reopening.

[Miserlou]

:[

It's been more than a year and the docs are still lying about this, is there anywhere to submit PRs to fix mistruthful docs?

[schmichael]

is there anywhere to submit PRs to fix mistruthful docs?

Yes! You can submit a PR against our entire website as its located in the website/ subdirectory: https://github.com/hashicorp/nomad/tree/master/website

The readme covers building/testing locally.

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