Chapter 10. Scaling Compute nodes with director Operator If you require more or fewer compute resources for your overcloud, you can scale the number of Compute nodes according to your requirements. 10.1. Adding Compute nodes to your overcloud with director Operator To add more Compute nodes to your overcloud, you must increase the node count for the compute OpenStackBaremetalSet resource. When a new node is provisioned, you create a new OpenStackConfigGenerator resource to generate a new set of Ansible playbooks, then use the OpenStackConfigVersion to create or update the OpenStackDeploy object to reapply the Ansible configuration to your overcloud. Procedure Check that you have enough hosts in a ready state in the openshift-machine-api namespace: For more information on managing your bare-metal hosts, see Managing bare metal hosts . Increase the count parameter for the compute OpenStackBaremetalSet resource: The OpenStackBaremetalSet resource automatically provisions the new nodes with the Red Hat Enterprise Linux base operating system. Wait until the provisioning process completes. Check the nodes periodically to determine the readiness of the nodes: Optional: Reserve static IP addresses for networks on the new Compute nodes. For more information, see Reserving static IP addresses for added Compute nodes with the OpenStackNetConfig CRD . Generate the Ansible playbooks by using OpenStackConfigGenerator . For more information, see Creating Ansible playbooks for overcloud configuration with the OpenStackConfigGenerator CRD . Apply the overcloud configuration. For more information, see Applying overcloud configuration with director Operator . Additional resources Managing bare metal hosts 10.2. Reserving static IP addresses for added Compute nodes with the OpenStackNetConfig CRD Use the OpenStackNetConfig CRD to define IP addresses that you want to reserve for the Compute node you added to your overcloud. Tip Use the following commands to view the OpenStackNetConfig CRD definition and specification schema: Procedure Open the openstacknetconfig.yaml file for the overcloud on your workstation. Add the following configuration to openstacknetconfig.yaml to create the OpenStackNetConfig custom resource (CR): Reserve static IP addresses for networks on specific nodes: Note Reservations have precedence over any autogenerated IP addresses. Save the openstacknetconfig.yaml definition file. Create the overcloud network configuration: Verification To verify that the overcloud network configuration is created, view the resources for the overcloud network configuration: View the OpenStackNetConfig API and child resources: If you see errors, check the underlying network-attach-definition and node network configuration policies: 10.3. Removing Compute nodes from your overcloud with director Operator To remove a Compute node from your overcloud, you must disable the Compute node, mark it for deletion, and decrease the node count for the compute OpenStackBaremetalSet resource. Note If you scale the overcloud with a new node in the same role, the node reuses the host names starting with lowest ID suffix and corresponding IP reservation. Prerequisites The workloads on the Compute nodes have been migrated to other Compute nodes. For more information, see Migrating virtual machine instances between Compute nodes . Procedure Access the remote shell for openstackclient : Identify the Compute node that you want to remove: Disable the Compute service on the node to prevent the node from scheduling new instances: Annotate the bare-metal node to prevent Metal 3 from starting the node: Replace <node> with the name of the BareMetalHost resource. Replace <metal3-pod> with the name of your metal3 pod. Log in to the Compute node as the root user and shut down the bare-metal node: If the Compute node is not accessible, complete the following steps: Log in to a Controller node as the root user. If Instance HA is enabled, disable the STONITH device for the Compute node: Replace <stonith_resource_name> with the name of the STONITH resource that corresponds to the node. The resource name uses the format <resource_agent>-<host_mac> . You can find the resource agent and the host MAC address in the FencingConfig section of the fencing.yaml file. Use IPMI to power off the bare-metal node. For more information, see your hardware vendor documentation. Retrieve the BareMetalHost resource that corresponds to the node that you want to remove: To change the status of the annotatedForDeletion parameter to true in the OpenStackBaremetalSet resource, annotate the BareMetalHost resource with osp-director.openstack.org/delete-host=true : Optional: Confirm that the annotatedForDeletion status has changed to true in the OpenStackBaremetalSet resource: Decrease the count parameter for the compute OpenStackBaremetalSet resource: When you reduce the resource count of the OpenStackBaremetalSet resource, you trigger the corresponding controller to handle the resource deletion, which causes the following actions: Director Operator deletes the corresponding IP reservations from OpenStackIPSet and OpenStackNetConfig for the deleted node. Director Operator flags the IP reservation entry in the OpenStackNet resource as deleted. Optional: To make the IP reservations of the deleted OpenStackBaremetalSet resource available for other roles to use, set the value of the spec.preserveReservations parameter to false in the OpenStackNetConfig object. Access the remote shell for openstackclient : Remove the Compute service entries from the overcloud: Check the Compute network agents entries in the overcloud and remove them if they exist: Exit from openstackclient :

Commands:
oc get baremetalhosts -n openshift-machine-api
oc patch openstackbaremetalset compute --type=merge --patch '{"spec":{"count":3}}' -n openstack
oc get baremetalhosts -n openshift-machine-api oc get openstackbaremetalset
oc describe crd openstacknetconfig oc explain openstacknetconfig.spec
apiVersion: osp-director.openstack.org/v1beta1 kind: OpenStackNetConfig metadata: name: openstacknetconfig
spec: reservations: controller-0: ipReservations: ctlplane: 172.22.0.120 compute-0: ipReservations: ctlplane: 172.22.0.140 internal_api: 172.17.0.40 storage: 172.18.0.40 tenant: 172.20.0.40 //The key for the ctlplane VIPs controlplane: ipReservations: ctlplane: 172.22.0.110 external: 10.0.0.10 internal_api: 172.17.0.10 storage: 172.18.0.10 storage_mgmt: 172.19.0.10 macReservations: {}
oc create -f openstacknetconfig.yaml -n openstack
oc get openstacknetconfig/openstacknetconfig
oc get openstacknetconfig/openstacknetconfig -n openstack oc get openstacknetattachment -n openstack oc get openstacknet -n openstack
oc get network-attachment-definitions -n openstack oc get nncp
oc rsh -n openstack openstackclient
openstack compute service list
openstack compute service set <hostname> nova-compute --disable
oc annotate baremetalhost <node> baremetalhost.metal3.io/detached=true oc logs --since=1h <metal3-pod> metal3-baremetal-operator | grep -i detach oc get baremetalhost <node> -o json | jq .status.operationalStatus "detached"
shutdown -h now
pcs stonith disable <stonith_resource_name>
oc get openstackbaremetalset compute -o json | jq '.status.baremetalHosts | to_entries[] | "\(.key) => \(.value | .hostRef)"' "compute-0, openshift-worker-3" "compute-1, openshift-worker-4"
oc annotate -n openshift-machine-api bmh/openshift-worker-3 osp-director.openstack.org/delete-host=true --overwrite
oc get openstackbaremetalset compute -o json -n openstack | jq .status { "baremetalHosts": { "compute-0": { "annotatedForDeletion": true, "ctlplaneIP": "192.168.25.105/24", "hostRef": "openshift-worker-3", "hostname": "compute-0", "networkDataSecretName": "compute-cloudinit-networkdata-openshift-worker-3", "provisioningState": "provisioned", "userDataSecretName": "compute-cloudinit-userdata-openshift-worker-3" }, "compute-1": { "annotatedForDeletion": false, "ctlplaneIP": "192.168.25.106/24", "hostRef": "openshift-worker-4", "hostname": "compute-1", "networkDataSecretName": "compute-cloudinit-networkdata-openshift-worker-4", "provisioningState": "provisioned", "userDataSecretName": "compute-cloudinit-userdata-openshift-worker-4" } }, "provisioningStatus": { "readyCount": 2, "reason": "All requested BaremetalHosts have been provisioned", "state": "provisioned" } }
oc patch openstackbaremetalset compute --type=merge --patch '{"spec":{"count":1}}' -n openstack
oc get osnet ctlplane -o json -n openstack | jq .reservations { "compute-0": { "deleted": true, "ip": "172.22.0.140" }, "compute-1": { "deleted": false, "ip": "172.22.0.100" }, "controller-0": { "deleted": false, "ip": "172.22.0.120" }, "controlplane": { "deleted": false, "ip": "172.22.0.110" }, "openstackclient-0": { "deleted": false, "ip": "172.22.0.251" }
oc rsh openstackclient -n openstack
openstack compute service list openstack compute service delete <service-id>
openstack network agent list for AGENT in USD(openstack network agent list --host <scaled-down-node> -c ID -f value) ; do openstack network agent delete USDAGENT ; done
exit