Chapter 6. Configuring bare-metal nodes to enable the creation of bare-metal instances from a bootable volume Important This feature is deprecated in Red Hat OpenStack Platform 17.0. Bug fixes and support are provided in RHOSP 17.0, but no new feature enhancements will be made. You can create volumes in the Block Storage service (cinder) and connect these volumes to bare-metal instances that you create with the Bare Metal Provisioning service (ironic). To enable your cloud users to create bare-metal instances from bootable volumes, complete the following tasks: Configure each bare-metal node to enable the launching of bare-metal instances from a bootable volume. Configure iSCSI kernel parameters on the boot disk. 6.1. Prerequisites The Bare Metal Provisioning service (ironic) connects bare-metal nodes to block storage volumes through an iSCSI interface. Therefore, the overcloud must be deployed with an iSCSI backend for the Block Storage service (cinder). To enable an iSCSI backend for the Block Storage service, set the CinderEnableIscsiBackend parameter to true and deploy the overcloud. Note You cannot use the Block Storage volume boot feature with a Red Hat Ceph Storage backend. 6.2. Configuring nodes to create bare-metal instances from a bootable volume You must configure each bare-metal node to enable it to provide the ability to launch bare-metal instances from a bootable volume. Procedure Source your overcloud credentials file: Replace <credentials_file> with the name of your credentials file, for example, overcloudrc . Set the iscsi_boot capability to true for each bare-metal node: Replace <node_uuid> with the ID of the bare-metal node. Set the storage-interface to cinder for each bare-metal node: Create an iSCSI connector for the node: Replace <connector_id> with a unique ID for each node, for example, iqn.2010-10.org.openstack.node<NUM> , where <NUM> is an incremented number for each node. 6.3. Configuring iSCSI kernel parameters on the boot disk You must configure the instance image to enable iSCSI booting in the kernel. Procedure Log in to the undercloud host as the stack user. Source the stackrc undercloud credentials file: Download a Red Hat Enterprise Linux KVM image in QCOW2 format from the Red Hat Enterprise Linux Product Software download page . Copy the image to the /home/stack/ directory on the undercloud. Mount the QCOW2 image and access it as the root user: Load the nbd kernel module: Connect the QCOW image as /dev/nbd0 : Check the partitions on the NBD: New Red Hat Enterprise Linux QCOW2 images contain only one partition, which is usually named /dev/nbd0p1 on the NBD. Create a mount point for the image: Mount the image: Mount your dev directory so that the image has access to device information on the host: Change the root directory to the mount point: Configure iSCSI on the image: Note Some commands in this step might report the following error: This error is not critical and you can ignore the error. Move the resolv.conf file to a temporary location: Create a temporary resolv.conf file to resolve DNS requests for the Red Hat Content Delivery Network. This example uses 8.8.8.8 for the nameserver: Register the mounted image to the Red Hat Content Delivery Network: Enter your user name and password when the command prompts you. Attach a subscription that contains Red Hat Enterprise Linux: Substitute <POOLID> with the pool ID of the subscription. Disable the default repositories: Enable the Red Hat Enterprise Linux repository: Red Hat Enterprise Linux 7: Red Hat Enterprise Linux 8: Install the iscsi-initiator-utils package: Unregister the mounted image: Restore the original resolv.conf file: Check the kernel version on the mounted image: For example, if the output is kernel-3.10.0-1062.el7.x86_64 , the kernel version is 3.10.0-1062.el7.x86_64 . Note this kernel version for the step. Note New Red Hat Enterprise Linux QCOW2 images have only one kernel version installed. If more than one kernel version is installed, use the latest one. Add the network and iscsi dracut modules to the initramfs image: Replace <KERNELVERSION> with the version number that you obtained from rpm -qa kernel . The following example uses 3.10.0-1062.el7.x86_64 as the kernel version: Exit from the mounted image back to your host operating system: Unmount the image: Unmount the dev directory from the temporary mount point: Unmount the image from the mount point: Disconnect the QCOW2 image from /dev/nbd0/ : Rebuild the grub menu configuration on the image: Install the libguestfs-tools package: Important If you install the libguestfs-tools package on the undercloud, disable iscsid.socket to avoid port conflicts with the tripleo_iscsid service on the undercloud: Set the libguestfs backend to use QEMU directly: Update the grub configuration on the image and set the rd.iscsi.firmware=1 kernel parameter on the boot disk: Upload the iSCSI-enabled image to the Image service (glance): Replace <image> with the name of the iSCSI-enabled image, for example, rhel-server-7.7-x86_64-kvm.qcow2 . Replace <image_ref> with a name to use to reference the image, for example, rhel-server-7.7-iscsi . 6.4. Creating a bare-metal instance from a bootable volume To verify that the bare-metal node can host bare-metal instances created from a bootable volume, create the bootable volume and launch an instance. Procedure Source your overcloud credentials file: Replace <credentials_file> with the name of your credentials file, for example, overcloudrc . Create a volume from the iSCSI-enabled instance image: Replace <image_ref> with the name or ID of the image to write to the volume, for example, rhel-server-7.7-iscsi . Create a bare-metal instance that uses the boot volume:

Commands:
source ~/<credentials_file>
openstack baremetal node set --property capabilities=iscsi_boot:true <node_uuid>
openstack baremetal node set --storage-interface cinder <node_uuid>
openstack baremetal volume connector create --node <node_uuid> --type iqn --connector-id <connector_id>
source ~/stackrc
sudo modprobe nbd
sudo qemu-nbd --connect=/dev/nbd0 <image>
sudo fdisk /dev/nbd0 -l
mkdir /tmp/mountpoint
sudo mount /dev/nbd0p1 /tmp/mountpoint/
sudo mount -o bind /dev /tmp/mountpoint/dev
sudo chroot /tmp/mountpoint /bin/bash
lscpu: cannot open /proc/cpuinfo: No such file or directory
mv /etc/resolv.conf /etc/resolv.conf.bak
echo "nameserver 8.8.8.8" > /etc/resolv.conf
subscription-manager register
subscription-manager list --all --available subscription-manager attach --pool <POOLID>
subscription-manager repos --disable "*"
subscription-manager repos --enable "rhel-7-server-rpms"
subscription-manager repos --enable "rhel-8-for-x86_64-baseos-eus-rpms"
yum install -y iscsi-initiator-utils
subscription-manager unregister
mv /etc/resolv.conf.bak /etc/resolv.conf
rpm -qa kernel
dracut --force --add "network iscsi" /boot/initramfs-<KERNELVERSION>.img <KERNELVERSION>
dracut --force --add "network iscsi" /boot/initramfs-3.10.0-1062.el7.x86_64.img 3.10.0-1062.el7.x86_64
exit
sudo umount /tmp/mountpoint/dev
sudo umount /tmp/mountpoint
sudo qemu-nbd --disconnect /dev/nbd0
sudo yum -y install libguestfs-tools
sudo systemctl disable --now iscsid.socket
export LIBGUESTFS_BACKEND=direct
guestfish -a /tmp/images/{{ dib_image }} -m /dev/sda3 sh "mount /dev/sda2 /boot/efi && rm /boot/grub2/grubenv && /sbin/grub2-mkconfig -o /boot/grub2/grub.cfg && cp /boot/grub2/grub.cfg /boot/efi/EFI/redhat/grub.cfg && grubby --update-kernel=ALL --args=\"rd.iscsi.firmware=1\" && cp /boot/grub2/grubenv /boot/efi/EFI/redhat/grubenv && echo Success"
openstack image create --disk-format qcow2 --container-format bare --file <image> <image_name>
source ~/<credentials_file>
openstack volume create --size 10 --image <image_ref> --bootable myBootableVolume
openstack server create --flavor baremetal --volume myBootableVolume --key default myBareMetalInstance