Appendix A. Deployment migration options This section includes topics related validation of DCN storage, as well as migrating or changing architectures. A.1. Validating edge storage Ensure that the deployment of central and edge sites are working by testing glance multi-store and instance creation. You can import images into glance that are available on the local filesystem or available on a web server. Note Always store an image copy in the central site, even if there are no instances using the image at the central location. Prerequisites Check the stores that are available through the Image service by using the glance stores-info command. In the following example, three stores are available: central, dcn1, and dcn2. These correspond to glance stores at the central location and edge sites, respectively: A.1.1. Importing from a local file You must upload the image to the central location's store first, then copy the image to remote sites. Ensure that your image file is in RAW format. If the image is not in raw format, you must convert the image before importing it into the Image service: A.1.2. Importing an image from a web server If the image is hosted on a web server, you can use the GlanceImageImportPlugins parameter to upload the image to multiple stores. This procedure assumes that the default image conversion plugin is enabled in glance. This feature automatically converts QCOW2 file formats into RAW images, which are optimal for Ceph RBD. You can confirm that a glance image is in RAW format by running the glance image-show ID | grep disk_format . Procedure Use the image-create-via-import parameter of the glance command to import an image from a web server. Use the --stores parameter. In this example, the qcow2 cirros image is downloaded from the official Cirros site, converted to RAW by glance, and imported into the central site and edge site 1 as specified by the --stores parameter. Alternatively you can replace --stores with --all-stores True to upload the image to all of the stores. A.1.3. Copying an image to a new site You can copy existing images from the central location to edge sites, which gives you access to previously created images at newly established locations. Use the UUID of the glance image for the copy operation: Note In this example, the --stores option specifies that the cirros image will be copied from the central site to edge sites dcn1 and dcn2. Alternatively, you can use the --all-stores True option, which uploads the image to all the stores that don't currently have the image. Confirm a copy of the image is in each store. Note that the stores key, which is the last item in the properties map, is set to central,dcn0,dcn1 .: Note Always store an image copy in the central site even if there is no VM using it on that site. A.1.4. Confirming that an instance at an edge site can boot with image based volumes You can use an image at the edge site to create a persistent root volume. Procedure Identify the ID of the image to create as a volume, and pass that ID to the openstack volume create command: Identify the volume ID of the newly created volume and pass it to the openstack server create command: You can verify that the volume is based on the image by running the rbd command within a ceph-mon container at the dcn0 edge site to list the volumes pool. Confirm that you can create a cinder snapshot of the root volume of the instance. Ensure that the server is stopped to quiesce data to create a clean snapshot. Use the --force option, because the volume status remains in-use when the instance is off. List the contents of the volumes pool on the dcn0 Ceph cluster to show the newly created snapshot. A.1.5. Confirming image snapshots can be created and copied between sites Verify that you can create a new image at the dcn0 site. Ensure that the server is stopped to quiesce data to create a clean snapshot: Copy the image from the dcn0 edge site back to the hub location, which is the default back end for glance: For more information on glance multistore operations, see Image service with multiple stores . A.2. Migrating to a spine and leaf deployment It is possible to migrate an existing cloud with a pre-existing network configuration to one with a spine leaf architecture. For this, the following conditions are needed: All bare metal ports must have their physical-network property value set to ctlplane . The parameter enable_routed_networks is added and set to true in undercloud.conf, followed by a re-run of the undercloud installation command, openstack undercloud install . Once the undercloud is re-deployed, the overcloud is considered a spine leaf, with a single leaf leaf0 . You can add additional provisioning leaves to the deployment through the following steps. Add the desired subnets to undercloud.conf as shown in Configuring routed spine-leaf in the undercloud . Re-run the undercloud installation command, openstack undercloud install . Add the desired additional networks and roles to the overcloud templates, network_data.yaml and roles_data.yaml respectively. Note If you are using the {{network.name}}InterfaceRoutes parameter in the network configuration file, then you'll need to ensure that the NetworkDeploymentActions parameter includes the value UPDATE . Finally, re-run the overcloud installation script that includes all relevant heat templates for your cloud deployment. A.3. Migrating to a multistack deployment You can migrate from a single stack deployment to a multistack deployment by treating the existing deployment as the central site, and adding additional edge sites. The ability to migrate from single to multistack in this release is a Technology Preview , and therefore is not fully supported by Red Hat. It should only be used for testing, and should not be deployed in a production environment. For more information about Technology Preview features, see Scope of Coverage Details . You cannot split the existing stack. You can scale down the existing stack to remove compute nodes if needed. These compute nodes can then be added to edge sites. Note This action creates workload interruptions if all compute nodes are removed. A.4. Backing up and restoring across edge sites You can back up and restore Block Storage service (cinder) volumes across distributed compute node (DCN) architectures in edge site and availability zones. The cinder-backup service runs in the central availability zone (AZ), and backups are stored in the central AZ. The Block Storage service does not store backups at DCN sites. Prerequisites The central site is deployed with the cinder-backup.yaml environment file located in /usr/share/openstack-tripleo-heat-templates/environments . For more information, see Block Storage backup service deployment . The Block Storage service (cinder) CLI is available. All sites must use a common openstack cephx client name. For more information, see Creating a Ceph key for external access . Procedure Create a backup of a volume in the first DCN site: Replace <volume_backup> with a name for the volume backup. Replace <az_central> with the name of the central availability zone that hosts the cinder-backup service. Replace <edge_volume> with the name of the volume that you want to back up. Note If you experience issues with Ceph keyrings, you might need to restart the cinder-backup container so that the keyrings copy from the host to the container successfully. Restore the backup to a new volume in the second DCN site: Replace <az_2> with the name of the availability zone where you want to restore the backup. Replace <new_volume> with a name for the new volume. Replace <volume_backup> with the name of the volume backup that you created in the step. Replace <volume_size> with a value in GB equal to or greater than the size of the original volume.

Commands:
glance stores-info +----------+----------------------------------------------------------------------------------+ | Property | Value | +----------+----------------------------------------------------------------------------------+ | stores | [{"default": "true", "id": "central", "description": "central rbd glance | | | store"}, {"id": "dcn0", "description": "dcn0 rbd glance store"}, | | | {"id": "dcn1", "description": "dcn1 rbd glance store"}] | +----------+----------------------------------------------------------------------------------+
file cirros-0.5.1-x86_64-disk.img cirros-0.5.1-x86_64-disk.img: QEMU QCOW2 Image (v3), 117440512 bytes qemu-img convert -f qcow2 -O raw cirros-0.5.1-x86_64-disk.img cirros-0.5.1-x86_64-disk.raw
Import the image into the default back end at the central site:
glance image-create --disk-format raw --container-format bare --name cirros --file cirros-0.5.1-x86_64-disk.raw --store central
glance image-create-via-import --disk-format qcow2 --container-format bare --name cirros --uri http://download.cirros-cloud.net/0.4.0/cirros-0.4.0-x86_64-disk.img --import-method web-download --stores central,dcn1
ID=USD(openstack image show cirros -c id -f value) glance image-import USDID --stores dcn0,dcn1 --import-method copy-image
openstack image show USDID | grep properties | properties | direct_url= rbd://d25504ce-459f-432d-b6fa-79854d786f2b/images/8083c7e7-32d8-4f7a-b1da-0ed7884f1076/snap , locations= [{u'url : u'rbd://d25504ce-459f-432d-b6fa-79854d786f2b/images/8083c7e7-32d8-4f7a-b1da-0ed7884f1076/snap', u'metadata': {u'store': u'central'}}, {u'url': u'rbd://0c10d6b5-a455-4c4d-bd53-8f2b9357c3c7/images/8083c7e7-32d8-4f7a-b1da-0ed7884f1076/snap', u'metadata': {u'store': u'dcn0'}}, {u'url': u'rbd://8649d6c3-dcb3-4aae-8c19-8c2fe5a853ac/images/8083c7e7-32d8-4f7a-b1da-0ed7884f1076/snap', u'metadata': {u'store': u'dcn1'}}] , os_glance_failed_import= ', os_glance_importing_to_stores= ', os_hash_algo='sha512 , os_hash_value= b795f047a1b10ba0b7c95b43b2a481a59289dc4cf2e49845e60b194a911819d3ada03767bbba4143b44c93fd7f66c96c5a621e28dff51d1196dae64974ce240e , os_hidden= False , stores= central,dcn0,dcn1 |
IMG_ID=USD(openstack image show cirros -c id -f value) openstack volume create --size 8 --availability-zone dcn0 pet-volume-dcn0 --image USDIMG_ID
VOL_ID=USD(openstack volume show -f value -c id pet-volume-dcn0) openstack server create --flavor tiny --key-name dcn0-key --network dcn0-network --security-group basic --availability-zone dcn0 --volume USDVOL_ID pet-server-dcn0
sudo podman exec ceph-mon-USDHOSTNAME rbd --cluster dcn0 -p volumes ls -l NAME SIZE PARENT FMT PROT LOCK volume-28c6fc32-047b-4306-ad2d-de2be02716b7 8 GiB images/8083c7e7-32d8-4f7a-b1da-0ed7884f1076@snap 2 excl USD
openstack server stop pet-server-dcn0 openstack volume snapshot create pet-volume-dcn0-snap --volume USDVOL_ID --force openstack server start pet-server-dcn0
sudo podman exec ceph-mon-USDHOSTNAME rbd --cluster dcn0 -p volumes ls -l NAME SIZE PARENT FMT PROT LOCK volume-28c6fc32-047b-4306-ad2d-de2be02716b7 8 GiB images/8083c7e7-32d8-4f7a-b1da-0ed7884f1076@snap 2 excl volume-28c6fc32-047b-4306-ad2d-de2be02716b7@snapshot-a1ca8602-6819-45b4-a228-b4cd3e5adf60 8 GiB images/8083c7e7-32d8-4f7a-b1da-0ed7884f1076@snap 2 yes
NOVA_ID=USD(openstack server show pet-server-dcn0 -f value -c id) openstack server stop USDNOVA_ID openstack server image create --name cirros-snapshot USDNOVA_ID openstack server start USDNOVA_ID
IMAGE_ID=USD(openstack image show cirros-snapshot -f value -c id) glance image-import USDIMAGE_ID --stores central --import-method copy-image
NetworkDeploymentActions: ['CREATE','UPDATE'])
cinder --os-volume-api-version 3.51 backup-create --name <volume_backup> --availability-zone <az_central> <edge_volume>
cinder --os-volume-api-version 3.51 create --availability-zone <az_2> --name <new_volume> --backup-id <volume_backup> <volume_size>