Bug 1900723

Summary: [RFE]: RHOSP16.x: Allowing update/modify the kernel args on already deployed node from director
Product: Red Hat OpenStack Reporter: Shravan Kumar Tiwari <shtiwari>
Component: tripleo-ansibleAssignee: Karthik Sundaravel <ksundara>
Status: CLOSED ERRATA QA Contact: Ella Shulman <eshulman>
Severity: high Docs Contact:
Priority: unspecified    
Version: 16.2 (Train)CC: hakhande, jamsmith, kfida, ksundara, mburns, mgarciac, nlevinki, nwolf, oblaut, shrjoshi, skramaja, spower, supadhya, yrachman
Target Milestone: AlphaKeywords: FutureFeature, Triaged
Target Release: 16.2 (Train on RHEL 8.4)   
Hardware: Unspecified   
OS: All   
Whiteboard:
Fixed In Version: tripleo-ansible-0.6.1.dev6-2.20210216015035.dfd20a8 Doc Type: Enhancement
Doc Text:
During stack update the `KernelArgs` could be modified or appended. You must perform a reboot of the affected nodes manually. + For example, if the current deployment has the following configuration, it is possible to change `hugepages=64`, or add or remove arguments during the stack update: + ---- `KernelArgs: "default_hugepagesz=1GB hugepagesz=1G hugepages=32 intel_iommu=on iommu=pt isolcpus=1-11,13-23" ---- + For example: + ---- KernelArgs: "default_hugepagesz=1GB hugepagesz=1G hugepages=64 intel_iommu=on iommu=pt isolcpus=1-24" KernelArgs: "isolcpus=1-11,13-23" ---- + [NOTE] Complete removal of `KernelArgs` during the update is not supported. Also `KernelArgs` could be newly added as well to an existing overcloud node, however the reboot was triggered in this case.
Story Points: ---
Clone Of: Environment:
Last Closed: 2021-09-15 07:10:23 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 1958940    
Bug Blocks:    

Description Shravan Kumar Tiwari 2020-11-23 15:26:44 UTC
Description of problem:

The need arises when kernel arguments of the node has to be updated/modified.
Update includes the 'host-config-and-reboot.yaml'. It is observed that 'HostParametersDeployment' is set only in case of create.

more ~/generated-tripleo-heat-templates/extraconfig/pre_network/host_config_and_reboot.yaml


HostParametersDeployment:
    type: OS::TripleO::Reboot::SoftwareDeployment
    condition: is_host_config_required
    properties:
      name: HostParametersDeployment
      server:  {get_param: server}
      config: {get_resource: HostParametersConfig}
      actions:
        if:
          - deployment_actions_empty
          - []
          - ['CREATE'] # Only do this on CREATE
      input_values:
        _KERNEL_ARGS_: {get_param: [RoleParameters, KernelArgs]}
        _TUNED_PROFILE_NAME_: {get_param: [RoleParameters, TunedProfileName]}
        _TUNED_CORES_: {get_param: [RoleParameters, IsolCpusList]}


Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
1.
2.
3.

Actual results:
Update of kernel form heat template is not achieved.

Expected results:
Update of kernel arguments supported from Director heat templates and nodes are not rebooted automatically rather user has an option to manually reboot the node to avoid sudden restart of all the affected nodes.

Additional info:

Comment 5 Karthik Sundaravel 2021-02-17 10:59:08 UTC
The patch [1] is merged in stable/train. 

a) With this patch the kernel args could be modified but would need manual reboot.

For example, if the current deployment has
KernelArgs: "default_hugepagesz=1GB hugepagesz=1G hugepages=32 intel_iommu=on iommu=pt isolcpus=1-11,13-23"
Its possible to change hugepages=64 or add/remove args. 

Possible changes
KernelArgs: "default_hugepagesz=1GB hugepagesz=1G hugepages=64 intel_iommu=on iommu=pt isolcpus=1-24"
KernelArgs: "isolcpus=1-11,13-23"

b) Complete removal of KernelArgs is not supported.

c) KernelArgs could be newly added as well to an existing overcloud node, however the reboot would be triggered in this case.



[1] https://review.opendev.org/c/openstack/tripleo-ansible/+/775216

Comment 19 errata-xmlrpc 2021-09-15 07:10:23 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (Red Hat OpenStack Platform (RHOSP) 16.2 enhancement advisory), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHEA-2021:3483