Validating single-node OpenShift cluster tuning for vDU application workloads

Before you can deploy virtual distributed unit (vDU) applications, you need to tune and configure the cluster host firmware and various other cluster configuration settings. Use the following information to validate the cluster configuration to support vDU workloads.

Additional resources

Use the following table as the basis to configure the cluster host firmware for vDU applications running on OKD 4.

The following table is a general recommendation for vDU cluster host firmware configuration. Exact firmware settings will depend on your requirements and specific hardware platform. Automatic setting of firmware is not handled by the zero touch provisioning pipeline.

Table 1. Recommended cluster host firmware settings
Firmware settingConfigurationDescription

HyperTransport (HT)

Enabled

HyperTransport (HT) bus is a bus technology developed by AMD. HT provides a high-speed link between the components in the host memory and other system peripherals.

UEFI

Enabled

Enable booting from UEFI for the vDU host.

CPU Power and Performance Policy

Performance

Set CPU Power and Performance Policy to optimize the system for performance over energy efficiency.

Uncore Frequency Scaling

Disabled

Disable Uncore Frequency Scaling to prevent the voltage and frequency of non-core parts of the CPU from being set independently.

Uncore Frequency

Maximum

Sets the non-core parts of the CPU such as cache and memory controller to their maximum possible frequency of operation.

Performance P-limit

Disabled

Disable Performance P-limit to prevent the Uncore frequency coordination of processors.

Enhanced Intel® SpeedStep Tech

Enabled

Enable Enhanced Intel SpeedStep to allow the system to dynamically adjust processor voltage and core frequency that decreases power consumption and heat production in the host.

Intel® Turbo Boost Technology

Enabled

Enable Turbo Boost Technology for Intel-based CPUs to automatically allow processor cores to run faster than the rated operating frequency if they are operating below power, current, and temperature specification limits.

Intel Configurable TDP

Enabled

Enables Thermal Design Power (TDP) for the CPU.

Configurable TDP Level

Level 2

TDP level sets the CPU power consumption required for a particular performance rating. TDP level 2 sets the CPU to the most stable performance level at the cost of power consumption.

Energy Efficient Turbo

Disabled

Disable Energy Efficient Turbo to prevent the processor from using an energy-efficiency based policy.

Hardware P-States

Enabled or Disabled

Enable OS-controlled P-States to allow power saving configurations. Disable P-states (performance states) to optimize the operating system and CPU for performance over power consumption.

Package C-State

C0/C1 state

Use C0 or C1 states to set the processor to a fully active state (C0) or to stop CPU internal clocks running in software (C1).

C1E

Disabled

CPU Enhanced Halt (C1E) is a power saving feature in Intel chips. Disabling C1E prevents the operating system from sending a halt command to the CPU when inactive.

Processor C6

Disabled

C6 power-saving is a CPU feature that automatically disables idle CPU cores and cache. Disabling C6 improves system performance.

Sub-NUMA Clustering

Disabled

Sub-NUMA clustering divides the processor cores, cache, and memory into multiple NUMA domains. Disabling this option can increase performance for latency-sensitive workloads.

Enable global SR-IOV and VT-d settings in the firmware for the host. These settings are relevant to bare-metal environments.

Enable both C-states and OS-controlled P-States to allow per pod power management.

Clusters running virtualized distributed unit (vDU) applications require a highly tuned and optimized configuration. The following information describes the various elements that you require to support vDU workloads in OKD 4 clusters.

Check that the MachineConfig custom resources (CRs) that you extract from the ztp-site-generate container are applied in the cluster. The CRs can be found in the extracted out/source-crs/extra-manifest/ folder.

The following MachineConfig CRs from the ztp-site-generate container configure the cluster host:

Table 2. Recommended GitOps ZTP MachineConfig CRs
MachineConfig CRDescription

01-container-mount-ns-and-kubelet-conf-master.yaml

01-container-mount-ns-and-kubelet-conf-worker.yaml

Configures the container mount namespace and kubelet configuration.

02-workload-partitioning.yaml

Configures workload partitioning for the cluster. Apply this MachineConfig CR when you install the cluster.

If you use the cpuPartitioningMode field in the SiteConfig CR to configure workload partitioning, you do not need to use the 02-workload-partitioning.yaml CR. Using the cpuPartitioningMode field is a Technology Preview feature in OKD 4.13. For more information, see “Workload partitioning in single-node OpenShift with GitOps ZTP”.

03-sctp-machine-config-master.yaml

03-sctp-machine-config-worker.yaml

Loads the SCTP kernel module. These MachineConfig CRs are optional and can be omitted if you do not require this kernel module.

04-accelerated-container-startup-master.yaml

04-accelerated-container-startup-worker.yaml

Configures accelerated startup for the cluster.

05-kdump-config-master.yaml

05-kdump-config-worker.yaml

06-kdump-master.yaml

06-kdump-worker.yaml

Configures kdump crash reporting for the cluster.

99-crio-disable-wipe-master.yaml

99-crio-disable-wipe-worker.yaml

Disables the automatic CRI-O cache wipe following cluster reboot.

Additional resources

The following Operators are required for clusters running virtualized distributed unit (vDU) applications and are a part of the baseline reference configuration:

  • Node Tuning Operator (NTO). NTO packages functionality that was previously delivered with the Performance Addon Operator, which is now a part of NTO.

  • PTP Operator

  • SR-IOV Network Operator

  • Red Hat OpenShift Logging Operator

  • Local Storage Operator

Always use the latest supported real-time kernel version in your cluster. Ensure that you apply the following configurations in the cluster:

  1. Ensure that the following additionalKernelArgs are set in the cluster performance profile:

    1. spec:
    2.   additionalKernelArgs:
    3.   - "rcupdate.rcu_normal_after_boot=0"
    4.   - "efi=runtime"
    5.   - "module_blacklist=irdma"

  2. Ensure that the performance-patch profile in the Tuned CR configures the correct CPU isolation set that matches the isolated CPU set in the related PerformanceProfile CR, for example:

    1. spec:
    2.   profile:
    3.     - name: performance-patch
    4.       # The 'include' line must match the associated PerformanceProfile name, for example:
    5.       # include=openshift-node-performance-${PerformanceProfile.metadata.name}
    6.       # When using the standard (non-realtime) kernel, remove the kernel.timer_migration override from the [sysctl] section
    7.       data: |
    8.         [main]
    9.         summary=Configuration changes profile inherited from performance created tuned
    10.         include=openshift-node-performance-openshift-node-performance-profile
    11.         [sysctl]
    12.         kernel.timer_migration=1
    13.         [scheduler]
    14.         group.ice-ptp=0:f:10:*:ice-ptp.*
    15.         group.ice-gnss=0:f:10:*:ice-gnss.*
    16.         [service]
    17.         service.stalld=start,enable
    18.         service.chronyd=stop,disable

Checking the realtime kernel version

Always use the latest version of the realtime kernel in your OKD clusters. If you are unsure about the kernel version that is in use in the cluster, you can compare the current realtime kernel version to the release version with the following procedure.

Prerequisites

  • You have installed the OpenShift CLI (oc).

  • You are logged in as a user with cluster-admin privileges.

  • You have installed podman.

Procedure

  1. Run the following command to get the cluster version:

    1. $ OCP_VERSION=$(oc get clusterversion version -o jsonpath='{.status.desired.version}{"\n"}')

  2. Get the release image SHA number:

    1. $ DTK_IMAGE=$(oc adm release info --image-for=driver-toolkit quay.io/openshift-release-dev/ocp-release:$OCP_VERSION-x86_64)

  3. Run the release image container and extract the kernel version that is packaged with cluster’s current release:

    1. $ podman run --rm $DTK_IMAGE rpm -qa | grep 'kernel-rt-core-' | sed 's#kernel-rt-core-##'

    Example output

    1. 4.18.0-305.49.1.rt7.121.el8_4.x86_64

    This is the default realtime kernel version that ships with the release.

    The realtime kernel is denoted by the string .rt in the kernel version.

Verification

Check that the kernel version listed for the cluster’s current release matches actual realtime kernel that is running in the cluster. Run the following commands to check the running realtime kernel version:

  1. Open a remote shell connection to the cluster node:

    1. $ oc debug node/<node_name>

  2. Check the realtime kernel version:

    1. sh-4.4# uname -r

    Example output

    1. 4.18.0-305.49.1.rt7.121.el8_4.x86_64

You can check that clusters are running the correct configuration. The following procedure describes how to check the various configurations that you require to deploy a DU application in OKD 4 clusters.

Prerequisites

  • You have deployed a cluster and tuned it for vDU workloads.

  • You have installed the OpenShift CLI (oc).

  • You have logged in as a user with cluster-admin privileges.

Procedure

  1. Check that the default OperatorHub sources are disabled. Run the following command:

    1. $ oc get operatorhub cluster -o yaml

    Example output

    1. spec:
    2.     disableAllDefaultSources: true

  2. Check that all required CatalogSource resources are annotated for workload partitioning (PreferredDuringScheduling) by running the following command:

    1. $ oc get catalogsource -A -o jsonpath='{range .items[*]}{.metadata.name}{" -- "}{.metadata.annotations.target\.workload\.openshift\.io/management}{"\n"}{end}'

    Example output

    1. certified-operators -- {"effect": "PreferredDuringScheduling"}
    2. community-operators -- {"effect": "PreferredDuringScheduling"}
    3. ran-operators (1)
    4. redhat-marketplace -- {"effect": "PreferredDuringScheduling"}
    5. redhat-operators -- {"effect": "PreferredDuringScheduling"}
    1CatalogSource resources that are not annotated are also returned. In this example, the ran-operators CatalogSource resource is not annotated and does not have the PreferredDuringScheduling annotation.

    In a properly configured vDU cluster, only a single annotated catalog source is listed.

  3. Check that all applicable OKD Operator namespaces are annotated for workload partitioning. This includes all Operators installed with core OKD and the set of additional Operators included in the reference DU tuning configuration. Run the following command:

    1. $ oc get namespaces -A -o jsonpath='{range .items[*]}{.metadata.name}{" -- "}{.metadata.annotations.workload\.openshift\.io/allowed}{"\n"}{end}'

    Example output

    1. default --
    2. openshift-apiserver -- management
    3. openshift-apiserver-operator -- management
    4. openshift-authentication -- management
    5. openshift-authentication-operator -- management

    Additional Operators must not be annotated for workload partitioning. In the output from the previous command, additional Operators should be listed without any value on the right side of the — separator.

  4. Check that the ClusterLogging configuration is correct. Run the following commands:

    1. Validate that the appropriate input and output logs are configured:

      1. $ oc get -n openshift-logging ClusterLogForwarder instance -o yaml

      Example output

      1. apiVersion: logging.openshift.io/v1
      2. kind: ClusterLogForwarder
      3. metadata:
      4.   creationTimestamp: "2022-07-19T21:51:41Z"
      5.   generation: 1
      6.   name: instance
      7.   namespace: openshift-logging
      8.   resourceVersion: "1030342"
      9.   uid: 8c1a842d-80c5-447a-9150-40350bdf40f0
      10. spec:
      11.   inputs:
      12.   - infrastructure: {}
      13.     name: infra-logs
      14.   outputs:
      15.   - name: kafka-open
      16.     type: kafka
      17.     url: tcp://10.46.55.190:9092/test
      18.   pipelines:
      19.   - inputRefs:
      20.     - audit
      21.     name: audit-logs
      22.     outputRefs:
      23.     - kafka-open
      24.   - inputRefs:
      25.     - infrastructure
      26.     name: infrastructure-logs
      27.     outputRefs:
      28.     - kafka-open
      29. ...

    2. Check that the curation schedule is appropriate for your application:

      1. $ oc get -n openshift-logging clusterloggings.logging.openshift.io instance -o yaml

      Example output

      1. apiVersion: logging.openshift.io/v1
      2. kind: ClusterLogging
      3. metadata:
      4.   creationTimestamp: "2022-07-07T18:22:56Z"
      5.   generation: 1
      6.   name: instance
      7.   namespace: openshift-logging
      8.   resourceVersion: "235796"
      9.   uid: ef67b9b8-0e65-4a10-88ff-ec06922ea796
      10. spec:
      11.   collection:
      12.     logs:
      13.       fluentd: {}
      14.       type: fluentd
      15.   curation:
      16.     curator:
      17.       schedule: 30 3 * * *
      18.     type: curator
      19.   managementState: Managed
      20. ...

  5. Check that the web console is disabled (managementState: Removed) by running the following command:

    1. $ oc get consoles.operator.openshift.io cluster -o jsonpath="{ .spec.managementState }"

    Example output

    1. Removed

  6. Check that chronyd is disabled on the cluster node by running the following commands:

    1. $ oc debug node/<node_name>

    Check the status of chronyd on the node:

    1. sh-4.4# chroot /host
    1. sh-4.4# systemctl status chronyd

    Example output

    1. ● chronyd.service - NTP client/server
    2.     Loaded: loaded (/usr/lib/systemd/system/chronyd.service; disabled; vendor preset: enabled)
    3.     Active: inactive (dead)
    4.       Docs: man:chronyd(8)
    5.             man:chrony.conf(5)

  7. Check that the PTP interface is successfully synchronized to the primary clock using a remote shell connection to the linuxptp-daemon container and the PTP Management Client (pmc) tool:

    1. Set the $PTP_POD_NAME variable with the name of the linuxptp-daemon pod by running the following command:

      1. $ PTP_POD_NAME=$(oc get pods -n openshift-ptp -l app=linuxptp-daemon -o name)

    2. Run the following command to check the sync status of the PTP device:

      1. $ oc -n openshift-ptp rsh -c linuxptp-daemon-container ${PTP_POD_NAME} pmc -u -f /var/run/ptp4l.0.config -b 0 'GET PORT_DATA_SET'

      Example output

      1. sending: GET PORT_DATA_SET
      2.   3cecef.fffe.7a7020-1 seq 0 RESPONSE MANAGEMENT PORT_DATA_SET
      3.     portIdentity            3cecef.fffe.7a7020-1
      4.     portState               SLAVE
      5.     logMinDelayReqInterval  -4
      6.     peerMeanPathDelay       0
      7.     logAnnounceInterval     1
      8.     announceReceiptTimeout  3
      9.     logSyncInterval         0
      10.     delayMechanism          1
      11.     logMinPdelayReqInterval 0
      12.     versionNumber           2
      13.   3cecef.fffe.7a7020-2 seq 0 RESPONSE MANAGEMENT PORT_DATA_SET
      14.     portIdentity            3cecef.fffe.7a7020-2
      15.     portState               LISTENING
      16.     logMinDelayReqInterval  0
      17.     peerMeanPathDelay       0
      18.     logAnnounceInterval     1
      19.     announceReceiptTimeout  3
      20.     logSyncInterval         0
      21.     delayMechanism          1
      22.     logMinPdelayReqInterval 0
      23.     versionNumber           2

    3. Run the following pmc command to check the PTP clock status:

      1. $ oc -n openshift-ptp rsh -c linuxptp-daemon-container ${PTP_POD_NAME} pmc -u -f /var/run/ptp4l.0.config -b 0 'GET TIME_STATUS_NP'

      Example output

      1. sending: GET TIME_STATUS_NP
      2.   3cecef.fffe.7a7020-0 seq 0 RESPONSE MANAGEMENT TIME_STATUS_NP
      3.     master_offset              10 (1)
      4.     ingress_time               1657275432697400530
      5.     cumulativeScaledRateOffset +0.000000000
      6.     scaledLastGmPhaseChange    0
      7.     gmTimeBaseIndicator        0
      8.     lastGmPhaseChange          0x0000'0000000000000000.0000
      9.     gmPresent                  true (2)
      10.     gmIdentity                 3c2c30.ffff.670e00
      1master_offset should be between -100 and 100 ns.
      2Indicates that the PTP clock is synchronized to a master, and the local clock is not the grandmaster clock.

    4. Check that the expected master offset value corresponding to the value in /var/run/ptp4l.0.config is found in the linuxptp-daemon-container log:

      1. $ oc logs $PTP_POD_NAME -n openshift-ptp -c linuxptp-daemon-container

      Example output

      1. phc2sys[56020.341]: [ptp4l.1.config] CLOCK_REALTIME phc offset  -1731092 s2 freq -1546242 delay    497
      2. ptp4l[56020.390]: [ptp4l.1.config] master offset         -2 s2 freq   -5863 path delay       541
      3. ptp4l[56020.390]: [ptp4l.0.config] master offset         -8 s2 freq  -10699 path delay       533

  8. Check that the SR-IOV configuration is correct by running the following commands:

    1. Check that the disableDrain value in the SriovOperatorConfig resource is set to true:

      1. $ oc get sriovoperatorconfig -n openshift-sriov-network-operator default -o jsonpath="{.spec.disableDrain}{'\n'}"

      Example output

      1. true

    2. Check that the SriovNetworkNodeState sync status is Succeeded by running the following command:

      1. $ oc get SriovNetworkNodeStates -n openshift-sriov-network-operator -o jsonpath="{.items[*].status.syncStatus}{'\n'}"

      Example output

      1. Succeeded

    3. Verify that the expected number and configuration of virtual functions (Vfs) under each interface configured for SR-IOV is present and correct in the .status.interfaces field. For example:

      1. $ oc get SriovNetworkNodeStates -n openshift-sriov-network-operator -o yaml

      Example output

      1. apiVersion: v1
      2. items:
      3. - apiVersion: sriovnetwork.openshift.io/v1
      4.   kind: SriovNetworkNodeState
      5. ...
      6.   status:
      7.     interfaces:
      8.     ...
      9.     - Vfs:
      10.       - deviceID: 154c
      11.         driver: vfio-pci
      12.         pciAddress: 0000:3b:0a.0
      13.         vendor: "8086"
      14.         vfID: 0
      15.       - deviceID: 154c
      16.         driver: vfio-pci
      17.         pciAddress: 0000:3b:0a.1
      18.         vendor: "8086"
      19.         vfID: 1
      20.       - deviceID: 154c
      21.         driver: vfio-pci
      22.         pciAddress: 0000:3b:0a.2
      23.         vendor: "8086"
      24.         vfID: 2
      25.       - deviceID: 154c
      26.         driver: vfio-pci
      27.         pciAddress: 0000:3b:0a.3
      28.         vendor: "8086"
      29.         vfID: 3
      30.       - deviceID: 154c
      31.         driver: vfio-pci
      32.         pciAddress: 0000:3b:0a.4
      33.         vendor: "8086"
      34.         vfID: 4
      35.       - deviceID: 154c
      36.         driver: vfio-pci
      37.         pciAddress: 0000:3b:0a.5
      38.         vendor: "8086"
      39.         vfID: 5
      40.       - deviceID: 154c
      41.         driver: vfio-pci
      42.         pciAddress: 0000:3b:0a.6
      43.         vendor: "8086"
      44.         vfID: 6
      45.       - deviceID: 154c
      46.         driver: vfio-pci
      47.         pciAddress: 0000:3b:0a.7
      48.         vendor: "8086"
      49.         vfID: 7

  9. Check that the cluster performance profile is correct. The cpu and hugepages sections will vary depending on your hardware configuration. Run the following command:

    1. $ oc get PerformanceProfile openshift-node-performance-profile -o yaml

    Example output

    1. apiVersion: performance.openshift.io/v2
    2. kind: PerformanceProfile
    3. metadata:
    4.   creationTimestamp: "2022-07-19T21:51:31Z"
    5.   finalizers:
    6.   - foreground-deletion
    7.   generation: 1
    8.   name: openshift-node-performance-profile
    9.   resourceVersion: "33558"
    10.   uid: 217958c0-9122-4c62-9d4d-fdc27c31118c
    11. spec:
    12.   additionalKernelArgs:
    13.   - idle=poll
    14.   - rcupdate.rcu_normal_after_boot=0
    15.   - efi=runtime
    16.   cpu:
    17.     isolated: 2-51,54-103
    18.     reserved: 0-1,52-53
    19.   hugepages:
    20.     defaultHugepagesSize: 1G
    21.     pages:
    22.     - count: 32
    23.       size: 1G
    24.   machineConfigPoolSelector:
    25.     pools.operator.machineconfiguration.openshift.io/master: ""
    26.   net:
    27.     userLevelNetworking: true
    28.   nodeSelector:
    29.     node-role.kubernetes.io/master: ""
    30.   numa:
    31.     topologyPolicy: restricted
    32.   realTimeKernel:
    33.     enabled: true
    34. status:
    35.   conditions:
    36.   - lastHeartbeatTime: "2022-07-19T21:51:31Z"
    37.     lastTransitionTime: "2022-07-19T21:51:31Z"
    38.     status: "True"
    39.     type: Available
    40.   - lastHeartbeatTime: "2022-07-19T21:51:31Z"
    41.     lastTransitionTime: "2022-07-19T21:51:31Z"
    42.     status: "True"
    43.     type: Upgradeable
    44.   - lastHeartbeatTime: "2022-07-19T21:51:31Z"
    45.     lastTransitionTime: "2022-07-19T21:51:31Z"
    46.     status: "False"
    47.     type: Progressing
    48.   - lastHeartbeatTime: "2022-07-19T21:51:31Z"
    49.     lastTransitionTime: "2022-07-19T21:51:31Z"
    50.     status: "False"
    51.     type: Degraded
    52.   runtimeClass: performance-openshift-node-performance-profile
    53.   tuned: openshift-cluster-node-tuning-operator/openshift-node-performance-openshift-node-performance-profile

    CPU settings are dependent on the number of cores available on the server and should align with workload partitioning settings. hugepages configuration is server and application dependent.

  10. Check that the PerformanceProfile was successfully applied to the cluster by running the following command:

    1. $ oc get performanceprofile openshift-node-performance-profile -o jsonpath="{range .status.conditions[*]}{ @.type }{' -- '}{@.status}{'\n'}{end}"

    Example output

    1. Available -- True
    2. Upgradeable -- True
    3. Progressing -- False
    4. Degraded -- False

  11. Check the Tuned performance patch settings by running the following command:

    1. $ oc get tuneds.tuned.openshift.io -n openshift-cluster-node-tuning-operator performance-patch -o yaml

    Example output

    1. apiVersion: tuned.openshift.io/v1
    2. kind: Tuned
    3. metadata:
    4.  creationTimestamp: "2022-07-18T10:33:52Z"
    5.  generation: 1
    6.  name: performance-patch
    7.  namespace: openshift-cluster-node-tuning-operator
    8.  resourceVersion: "34024"
    9.  uid: f9799811-f744-4179-bf00-32d4436c08fd
    10. spec:
    11.  profile:
    12.  - data: |
    13.      [main]
    14.      summary=Configuration changes profile inherited from performance created tuned
    15.      include=openshift-node-performance-openshift-node-performance-profile
    16.      [bootloader]
    17.      cmdline_crash=nohz_full=2-23,26-47 (1)
    18.      [sysctl]
    19.      kernel.timer_migration=1
    20.      [scheduler]
    21.      group.ice-ptp=0:f:10:*:ice-ptp.*
    22.      [service]
    23.      service.stalld=start,enable
    24.      service.chronyd=stop,disable
    25.    name: performance-patch
    26.  recommend:
    27.  - machineConfigLabels:
    28.      machineconfiguration.openshift.io/role: master
    29.    priority: 19
    30.    profile: performance-patch
    1The cpu list in cmdline=nohz_full= will vary based on your hardware configuration.

  12. Check that cluster networking diagnostics are disabled by running the following command:

    1. $ oc get networks.operator.openshift.io cluster -o jsonpath='{.spec.disableNetworkDiagnostics}'

    Example output

    1. true

  13. Check that the Kubelet housekeeping interval is tuned to slower rate. This is set in the containerMountNS machine config. Run the following command:

    1. $ oc describe machineconfig container-mount-namespace-and-kubelet-conf-master | grep OPENSHIFT_MAX_HOUSEKEEPING_INTERVAL_DURATION

    Example output

    1. Environment="OPENSHIFT_MAX_HOUSEKEEPING_INTERVAL_DURATION=60s"

  14. Check that Grafana and alertManagerMain are disabled and that the Prometheus retention period is set to 24h by running the following command:

    1. $ oc get configmap cluster-monitoring-config -n openshift-monitoring -o jsonpath="{ .data.config\.yaml }"

    Example output

    1. grafana:
    2.  enabled: false
    3. alertmanagerMain:
    4.  enabled: false
    5. prometheusK8s:
    6.   retention: 24h

    1. Use the following commands to verify that Grafana and alertManagerMain routes are not found in the cluster:

      1. $ oc get route -n openshift-monitoring alertmanager-main
      1. $ oc get route -n openshift-monitoring grafana

      Both queries should return Error from server (NotFound) messages.

  15. Check that there is a minimum of 4 CPUs allocated as reserved for each of the PerformanceProfile, Tuned performance-patch, workload partitioning, and kernel command line arguments by running the following command:

    1. $ oc get performanceprofile -o jsonpath="{ .items[0].spec.cpu.reserved }"

    Example output

    1. 0-3

    Depending on your workload requirements, you might require additional reserved CPUs to be allocated.