design doc for the externally-manage-pf support #476
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Thanks for your PR,
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doc/design/externally-manage-pf.md
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| The feature is needed to allow the operator to only configure a subset of virtual functions. | ||
| This allows a third party component like nmstate, kubernetes-nmstate, NetworkManager to handle the creation | ||
| and the usage of the virtual functions on the system. |
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what do you mean by usage in the system ?
doc/design/externally-manage-pf.md
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| ### Use Cases | ||
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| * As a user I want to use a virtual function for SDN network |
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why cant you do it today ? i think this needs more clarification.
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btw, why isnt using sriov-operator in systemd mode good enough for openshift ovn-k hw offload use case ?
because they ended up not requesting an sriov resource ? because they didnt want cluster network operator to depend on sriov operator ? (maybe it should for this case IMO, but i dont have the full context...)
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when I start working on the systemd I was thinking this will be a solution for both HW-offload and any request to use a vf as the primary interface.
But at the end the use-case for the systemd mode if you ask me is to have a faster boot/sriov configuration when you request a large number of virtual functions.
Even with systemd you have some limitations that only the externally manage can handle like:
- Installation time - meaning you want to use the vf even before you deploy k8s because after the deployment moving the IP address from the PF to the virtual function is super complicated. (even for vanilla deployment not OCP)
- same for also storage you may want a storage connection via a VF for the baremetal machine via a VF even before you deploy k8s on that machine.
The request is to be able and have parity with just creating vlan interfaces from the PF to split the host traffic.
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lets extend the usecases then to reflect that.
i.e for SDN the network need to be configured before k8s is deployed and these VFs should be available at system startup before pods start running.
also lets add storage use-case where you need VFs to be configured and available for the storage subsystem before k8s is deployed / pods spinning up at system startup.
doc/design/externally-manage-pf.md
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| * Allow the SR-IOV operator to handle the configure and pod allocation of a subset of virtual functions. | ||
| * Allow the user to Allocate the number of virtual functions he wants for the system and the subset he wants for pods | ||
| * Not resetting the numOfVfs for PFs that the operator didn't configure |
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that the operator didint configure -> that are externally managed.
doc/design/externally-manage-pf.md
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| Create a flow in the SR-IOV operator where the user can request a configuration for a subset of virtual functions. | ||
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| The operator will first validate and the requested PF contains the requested amount of virtual functions allocated, |
doc/design/externally-manage-pf.md
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| Create a flow in the SR-IOV operator where the user can request a configuration for a subset of virtual functions. | ||
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| The operator will first validate and the requested PF contains the requested amount of virtual functions allocated, | ||
| Then the operator will configure the subset of virtual functions with the request driver and will update the device plugin |
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what about MTU, GUID, MAC, driver unbind/bind for rdma?
can you add a list of the current operations sriov operator (and config daemon) performs on PF and VF
and then list the set of operations it will perform on a VF that belongs to externally manager PF ?
doc/design/externally-manage-pf.md
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| ``` | ||
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| #### Validation | ||
| The SR-IOV operator will do a validation webhook to check if the requested `numVfs` is equal to what the user allocate |
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until today, did we prevent the creation of SriovNetworkNodePolicy because an sriovNetworkNodeState did not have status ?
wont this affect UX, say i have a provisioning infra where i deploy sriov operator then create its CRs
i would now need to split between the two steps, add custom wait logic to make sure i can create the CR, this is not automation friendly.
also what happens on scale-up of the cluster ? (after you already have a bunch of externally managed policies)
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it's the case already today if you enable the webhook.
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what is the case today ? can you provide some examples (im not too familiar with the webhook flows)
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Thanks for your PR,
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Hi @adrianchiris let me know if I manage to answer all the comments. |
doc/design/externally-manage-pf.md
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| ## Summary | ||
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| Allow the SR-IOV operator to configure and allocate a subset of virtual functions from a physical function not | ||
| configured by the operator |
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"...not configured by the operator": I think this summary is a bit confusing for a new reader. I think what is meant is by "...from a physical function that is configured externally from SR-IOV network operator" Wdyt?
doc/design/externally-manage-pf.md
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| ## Summary | ||
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| Allow the SR-IOV operator to configure and allocate a subset of virtual functions from a physical function not |
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NIT: SR-IOV network operator throughout the document.
doc/design/externally-manage-pf.md
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| The feature is needed to allow the operator to only configure a subset of virtual functions. | ||
| This allows a third party component like nmstate, kubernetes-nmstate, NetworkManager to handle the creation | ||
| and the usage of the virtual functions on the system.Some of the examples are using the virtual function as the primary |
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Nit: Missing "space" between "." and "Some".
doc/design/externally-manage-pf.md
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| ### Use Cases | ||
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| * As a user I want to use a virtual function for SDN network |
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lets extend the usecases then to reflect that.
i.e for SDN the network need to be configured before k8s is deployed and these VFs should be available at system startup before pods start running.
also lets add storage use-case where you need VFs to be configured and available for the storage subsystem before k8s is deployed / pods spinning up at system startup.
doc/design/externally-manage-pf.md
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| #### Webhook | ||
| For the webhook we add more validations when the policy contains `ExternallyManaged: true` | ||
| * `numVfs` in the policy equal is equal or lower the number of virtual functions on the system | ||
| * `MTU` in the policy equals the MTU we discover on the PF |
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need to validate link type as well IMO
doc/design/externally-manage-pf.md
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| ### Test Plan | ||
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| * Should not allow to create a policy if there are no vfs configured |
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nit: a policy with externallyManaged==true
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done that was the name of the tests I already did on the PR :)
doc/design/externally-manage-pf.md
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| This is where most of the changes for this feature are implemented. | ||
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| First step we will do a validation same as on the webhook to check the PF have everything we need to apply the requested | ||
| policy, by checking the `numVfs` and `MTU`. |
doc/design/externally-manage-pf.md
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| First step we will do a validation same as on the webhook to check the PF have everything we need to apply the requested | ||
| policy, by checking the `numVfs` and `MTU`. | ||
| Next config-daemon will skip all the PF configuration like `numVfs` and `MTU`. he will only preform the virtual function | ||
| driver allocation, administrative mac allocation and MTU. Last step as always will be to reset the device plugin so |
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allocation -> binding
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also need to update this part with RDMA bits
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Thanks for your PR,
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| pfNames: ["ens3f0#5-9"] | ||
| nodeSelector: | ||
| node-role.kubernetes.io/worker: "" | ||
| numVfs: 10 |
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One of the goals is "Not resetting the numOfVfs for PFs that are externally managed" then should we somehow block out this parameter? We shouldn't need to provide this when we can get the number of VFs created from sysfs sriov_numvfs.
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no we want to have this so we can still do validation.
with the externally manage the numVfs MUST be lower or equal to the number of vfs configured in the system
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I thought the numVfs must be equal since the significance of numVfs is configuring the number of VFs via sysfs sriov_numvfs. I can't see a reason which numVfs < sysfs sriov_numvfs.
Wouldn't we always want to have numVfs == sysfs sriov_numvfs?
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it can also be lower then sysfs sriov_numvfs to allow increasing the num of vfs
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| ### Use Cases | ||
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| * As a user I want to use a virtual function for SDN network, for SDN the network need to be configured before |
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For this particular use case, it is similar to what we have for OvS Hardware Offload. Do you expect for this use case that the use sriov-network-operator in systemd would be needed?
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it depend.
the user can select what he want.
if he want to have the SDN from day 0 (installation) then use the externallyManage if he want to configure this after the cluster is ready (and the SDN support it like for HWoffload) then use the systemd mode
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I think it maybe helpful to put a note in the document saying that systemd mode is recommended for some of the example use cases.
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done I added as a non goal for this feature
doc/design/externally-manage-pf.md
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| The SR-IOV network operator will do a validation webhook to check if the requested `numVfs` is equal to what the user allocate | ||
| if not it will reject the policy creation. | ||
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| The SR-IOV network operator will do a validation webhook to check if the requested MTU is equal to what exist on the PF |
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I think we should block out any setting of the MTU when externallyManaged = true. In the code we should automatically set the MTU of the VF from the PF.
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we allow the user to select a different MTU for the VF that must be lower or equal the one from the PF. (because we don't change the MTU on the PF in this mode
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I thought if the VF MTU is lower than the PF MTU it can cause issues. From the text, highlighted here, it seems that the MTU on the VF must be equal to the MTU on the PF which is also my expectations.
So the user has no choice in MTU values? It is a "must" for the MTU of VF = MTU of PF?
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i think this sentence should be changed and validation webhook should check that the configured MTU is less/eq to MTU configured on PF.
also im not aware of any limitation where VF MTU < PF MTU
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| #### Webhook | ||
| For the webhook we add more validations when the policy contains `ExternallyManaged: true` | ||
| * `numVfs` in the policy equal is equal or lower the number of virtual functions on the system |
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I think it is a better UX if the user no longer needs to provide these values for externally managed. One less configuration that needs to be copied and pasted from another configuration (e.g. nmstate). It would be better to just blindly inherit these values. Wdyt?
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I will like to have this one because we do a lot of validation and stuff on the code with it when we have multiple policies.
we can change this in the future if we see customer complaining
doc/design/externally-manage-pf.md
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| First step we will do a validation same as on the webhook to check the PF have everything we need to apply the requested | ||
| policy, by checking the `numVfs`, `MTU` and `LinkType`. | ||
| Next config-daemon will skip all the PF configuration like `numVfs`, `MTU` and `LinkType`. he will only preform the virtual function |
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SP: "preform" to "perform"
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Thanks for your PR,
To skip the vendors CIs use one of:
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doc/design/externally-manage-pf.md
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| ### Goals | ||
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| * Allow the SR-IOV network operator to handle the configure and pod allocation of a subset of virtual functions |
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nit: configure -> configuration
of a subset of virtual functions
of some or all virtual functions
i suggest to add at the end:
while PF configuration are managed by an external entity.
doc/design/externally-manage-pf.md
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| * Allow the SR-IOV network operator to handle the configure and pod allocation of a subset of virtual functions | ||
| * Allow the user to Allocate the number of virtual functions he wants for the system and the subset he wants for pods | ||
| * Not resetting the numOfVfs for PFs that are externally managed |
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i dont think its a goal, but an implementation detail that emerges from the fact that some virtual functions are reserved for system use, hence the operator must not reset the number of VFs.
doc/design/externally-manage-pf.md
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| ## Proposal | ||
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| Create a sub-flow in the SR-IOV network operator where the user can request a configuration for a subset of virtual functions |
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for a subset of virtual functions
for all/subset of virtual functions
doc/design/externally-manage-pf.md
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| The operator will first validate the requested PF contains the requested amount of virtual functions allocated, it | ||
| will also validate the requested MTU is configured as expected on the PF. | ||
| The `sriovNetworkNodeState.status.SyncStatus` field will be report a `Failed` |
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If that is not the case ...
doc/design/externally-manage-pf.md
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| 2. Configure the MTU on the PF | ||
| 3. Copy the Administrative mac address from the VFs | ||
| 4. Bind the right driver for the VF | ||
| 5. Create SR-IOV device plugin pools |
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- restart sriov network device plugin
device plugin configs are updated by controller regardless of daemon flow IIRC
doc/design/externally-manage-pf.md
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| The SR-IOV network operator will do a validation webhook to check if the requested `numVfs` is equal to what the user allocate | ||
| if not it will reject the policy creation. | ||
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| The SR-IOV network operator will do a validation webhook to check if the requested MTU is equal to what exist on the PF |
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i think this sentence should be changed and validation webhook should check that the configured MTU is less/eq to MTU configured on PF.
also im not aware of any limitation where VF MTU < PF MTU
doc/design/externally-manage-pf.md
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| ### Upgrade & Downgrade considerations | ||
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| The feature supports both Upgrade and Downgrade as we are introducing a new field in the API |
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downgrade will cause the operator to treat an externally managed PF as non externally managed and actually configure PF, this may cause conflicts in the system.
imo the only concern here is documenting this.
doc/design/externally-manage-pf.md
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| Last step as always will be to reset the device plugin so | ||
| kubelet will be able to discover the SR-IOV devices. | ||
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| The config-daemon will also save on the node a cache of the last applied policy. this is needed to be able and understand |
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nit: cache -> cache (file)
doc/design/externally-manage-pf.md
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| kubelet will be able to discover the SR-IOV devices. | ||
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| The config-daemon will also save on the node a cache of the last applied policy. this is needed to be able and understand | ||
| if we need to reset the PF configuration(`ExternallyManaged` was false) or not when o policy is removed. |
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Thanks for your PR,
To skip the vendors CIs use one of:
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Hi @adrianchiris please give it another look |
doc/design/externally-manage-pf.md
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| Last step as always will be to reset the device plugin so | ||
| kubelet will be able to discover the SR-IOV devices. | ||
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| The config-daemon will also save on the node a cache (file) of the last applied policy. this is needed to be able and understand |
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I'm not a fan of such behaviour but this could be usefull for other features like systemd mode, drain controller, so it would be good implement this in a separate PR
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if possible, I would like to leave as part of this PR as it's already integrated.
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| ### Test Plan | ||
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| * Should not allow to create a policy with externallyManaged true if there are no vfs configured |
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we need to support a case when VFs will be configured later
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we can do it. BUT the user will need to disable the webhook because that is not the right way to do it.
the network must be ready before kubelet start of not then just let the operator create the vfs.
or use systemd mode
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Thanks for your PR,
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Signed-off-by: Sebastian Sch <[email protected]>
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Thanks for your PR,
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