Adds functionality to apply constraints to a LXD container spec #8869
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Constraints for CPU cores, memory and instance type are supported.
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Ping @pmatulis to sync regarding docs. |
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Merge check failure looks related to https://bugs.launchpad.net/juju/+bug/1778986. |
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Same again. !!build!! |
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How hard would it be to support something like cpu affinity?
https://stgraber.org/2016/03/26/lxd-2-0-resource-control-412/
(I'm quite surprised about limits.cpu, how do you specify just the 3rd cpu, because it looks like:
limits.cpu 0,3
means only cpu 0 and 3
but
limits.cpu 2
means limit to '2' cpus.
I suppose it is whether the given item looks like a list?
Maybe
limits.cpu 2,
?
Anyway, it has been a field request to be able to constrain containers in that fashion, and it feels like this starts to open up that possibility. We should discuss syntax, etc.
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I recall there was some trepidation regarding using constraints (get me a machine satisfying these I.e. "at least") for container limits (at most). There is nothing in constraints.Value that obviously does as a pass through to pinning CPUs, but we can thrash that out in said discussions. |
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@manadart Confirm that these LXD constraints are maximums while traditional constraints are minimums? |
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@pmatulis Indeed, confirmed. |
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I don't think that's really going to be easy to explain. I mean obviously, we can document it, but it means every time we mention constraints we have to say "(* not LXD)" or whatever. Unless I am misunderstanding. Also, it will actually mix the types of constraint in a single command e.g. in future when networks are added. |
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I will discuss with @jam and/or @mitechie and/or @howbazaar on how we should approach the concern here. |
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Note that the KVM container manager already implements constraints in similar fashion. |
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@jameinel Down the page in the comments section of that post, the single core pinning question was asked. The answer is to use the range syntax.
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#8891 ## Description of change Removes the constrain validation added in #8869 and passes constraints through to LXD as config, as they are supplied. This changes behaviour from #8869 where specifying an instance-type would override settings for CPU cores and/or memory. LXD's behaviour, now deferred to, is for any specific CPU/mem constraints to override those implied by an instance type _even when they are lower_. ## QA steps Only CPU and Memory ```juju add-machine lxd:0 --constraints "cores=2 mem=1G"``` - Check the LXD config for the new container and verify that: - limits.cpu = "2" and; - limits.memory = "1024MB" Specific Overrides Instance Type ```juju add-machine lxd:0 --constraints "cores=2 mem=2G instance-type=t2.micro"``` - Check the LXD config for the new container and verify that: - limits.cpu = "2" and; - limits.memory = "2048MB" Merged ```juju add-machine lxd:0 --constraints "mem=2G instance-type=t2.micro"``` - Check the LXD config for the new container and verify that: - limits.cpu = "1" and; - limits.memory = "2048MB" ## Documentation changes This changes the documentation requirements from #8869. ## Bug reference N/A
#8889 ## Description of change This is a backport of functionality added to the development branch, for supporting constraints and image types when provisioning LXD container machines. It cherry picks all commits from these PRs: - #8825 - #8838 - #8869 - #8891 ## QA steps See: #8891 ## Documentation changes Yes. ## Bug reference N/A
Description of change
This change introduces constraints support for LXD container machines.
The currently supported constraints are:
Instance types are congruent with AWS, GCE and Azure types. Those are listed here:
https://github.com/dustinkirkland/instance-type/tree/master/yaml
If an instance type constraint is supplied and any of CPU cores or memory are also supplied, these are ignored and a warning indicating such is logged.
Given recent networking changes, we should also be able to filter networking devices based on space constraints in a future patch.
QA steps
juju add-machine lxd:0 --constraints "cores=2 mem=1G"juju add-machine lxd:0 --constraints "cores=2 mem=1G instance-type=t2.micro"Documentation changes
Support for this enhancement should be documented.
Bug reference
N/A