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10.2. Deploying the Real-time Compute Role

Red Hat OpenStack Platform Director provides the template for the ComputeRealTime role, which you can then use to deploy Real-time Compute nodes. However, you must perform additional steps to designate Compute nodes for real-time.

  1. Based on the /usr/share/openstack-tripleo-heat-templates/environments/compute-real-time-example.yaml file, create a compute-real-time.yaml environment file that sets the parameters for the ComputeRealTime role. 

    cp /usr/share/openstack-tripleo-heat-templates/environments/compute-real-time-example.yaml /home/stack/templates/compute-real-time.yaml

    The file must include values for the following parameters:

    • IsolCpusList and NovaVcpuPinSet. List of isolated CPU cores and virtual CPU pins to reserve for real-time workloads. This value depends on the CPU hardware of your Real-time Compute nodes.
    • KernelArgs. Arguments to pass to the kernel of the Real-time Compute nodes. For example, you can use default_hugepagesz=1G hugepagesz=1G hugepages=<number_of_1G_pages_to_reserve> hugepagesz=2M hugepages=<number_of_2M_pages> to define the memory requirements of guests that have huge pages with multiple sizes. In this example, the default size is 1GB but you can also reserve 2M huge pages.

  2. Add the ComputeRealTime role to your roles data file and regenerate the file. For example: 

    $ openstack overcloud roles generate -o /home/stack/templates/rt_roles_data.yaml Controller Compute ComputeRealTime

    This command generates a ComputeRealTime role with contents similar to the following example, and also sets the ImageDefault option to overcloud-realtime-compute. 

    ###############################################################
# Role: ComputeRealTime                                                               #
###############################################################

- name: ComputeRealTime
  description: |
    Compute role that is optimized for real-time behaviour. When using this role
    it is mandatory that an overcloud-realtime-compute image is available and
    the role specific parameters IsolCpusList and NovaVcpuPinSet are set
    accordingly to the hardware of the real-time compute nodes.
  CountDefault: 1
  networks:
    - InternalApi
    - Tenant
    - Storage
  HostnameFormatDefault: '%stackname%-computerealtime-%index%'
  disable_upgrade_deployment: True
  ImageDefault: overcloud-realtime-compute
  RoleParametersDefault:
    TunedProfileName: "realtime-virtual-host"
    KernelArgs: ""      # these must be set in an environment file or similar
    IsolCpusList: ""    # according to the hardware of real-time nodes
    NovaVcpuPinSet: ""  #
  ServicesDefault:
    - OS::TripleO::Services::Aide
    - OS::TripleO::Services::AuditD
    - OS::TripleO::Services::CACerts
    - OS::TripleO::Services::CephClient
    - OS::TripleO::Services::CephExternal
    - OS::TripleO::Services::CertmongerUser
    - OS::TripleO::Services::Collectd
    - OS::TripleO::Services::ComputeCeilometerAgent
    - OS::TripleO::Services::ComputeNeutronCorePlugin
    - OS::TripleO::Services::ComputeNeutronL3Agent
    - OS::TripleO::Services::ComputeNeutronMetadataAgent
    - OS::TripleO::Services::ComputeNeutronOvsAgent
    - OS::TripleO::Services::Docker
    - OS::TripleO::Services::Fluentd
    - OS::TripleO::Services::Ipsec
    - OS::TripleO::Services::Iscsid
    - OS::TripleO::Services::Kernel
    - OS::TripleO::Services::LoginDefs
    - OS::TripleO::Services::MySQLClient
    - OS::TripleO::Services::NeutronBgpVpnBagpipe
    - OS::TripleO::Services::NeutronLinuxbridgeAgent
    - OS::TripleO::Services::NeutronVppAgent
    - OS::TripleO::Services::NovaCompute
    - OS::TripleO::Services::NovaLibvirt
    - OS::TripleO::Services::NovaMigrationTarget
    - OS::TripleO::Services::Ntp
    - OS::TripleO::Services::ContainersLogrotateCrond
    - OS::TripleO::Services::OpenDaylightOvs
    - OS::TripleO::Services::Rhsm
    - OS::TripleO::Services::RsyslogSidecar
    - OS::TripleO::Services::Securetty
    - OS::TripleO::Services::SensuClient
    - OS::TripleO::Services::SkydiveAgent
    - OS::TripleO::Services::Snmp
    - OS::TripleO::Services::Sshd
    - OS::TripleO::Services::Timezone
    - OS::TripleO::Services::TripleoFirewall
    - OS::TripleO::Services::TripleoPackages
    - OS::TripleO::Services::Vpp
    - OS::TripleO::Services::OVNController
    - OS::TripleO::Services::OVNMetadataAgent
    - OS::TripleO::Services::Ptp

    For general information about custom roles and about the roles-data.yaml, see the Roles section.

  3. Create the compute-realtime flavor to tag nodes that you want to designate for real-time workloads. For example: 

    $ source ~/stackrc
$ openstack flavor create --id auto --ram 6144 --disk 40 --vcpus 4 compute-realtime
$ openstack flavor set --property "cpu_arch"="x86_64" --property "capabilities:boot_option"="local" --property "capabilities:profile"="compute-realtime" compute-realtime

  4. Tag each node that you want to designate for real-time workloads with the compute-realtime profile. 

    $ openstack baremetal node set --property capabilities='profile:compute-realtime,boot_option:local' <NODE UUID>

  5. Map the ComputeRealTime role to the compute-realtime flavor by creating an environment file with the following content: 

    parameter_defaults:
  OvercloudComputeRealTimeFlavor: compute-realtime

  6. Run the openstack overcloud deploy command with the -e option and specify all the environment files that you created, as well as the new roles file. For example: 

    $ openstack overcloud deploy -r /home/stack/templates/rt~/my_roles_data.yaml  -e /home/stack/templates/compute-real-time.yaml <FLAVOR_ENV_FILE>
    注記

    If you want to run additional real-time instances on the same Compute node, you can change the priority of the instances in the realtime_schedule_priority paremeter in the nova.conf file.