Chapter 3. Overcloud Images

The director requires several disk images for provisioning Overcloud nodes. This includes:

Obtain these images from the rhosp-director-images and rhosp-director-images-ipa packages:

$ sudo dnf install rhosp-director-images rhosp-director-images-ipa

Extract the archives to the images directory on the stack user’s home (/home/stack/images):

$ cd ~/images
$ for i in /usr/share/rhosp-director-images/overcloud-full-latest-16.0.tar /usr/share/rhosp-director-images/ironic-python-agent-latest-16.0.tar; do tar -xvf $i; done

Some situations might require you to modify the initial ramdisk. For example, you might require a certain driver available when you boot the nodes during the introspection or provisioning processes. The following procedure shows how to modify an initial ramdisk. In the context of the Overcloud, this includes either:

This procedure adds an additional RPM package to the ironic-python-agent.initramfs ramdisk as an example.

Log in as the root user and create a temporary directory for the ramdisk

# mkdir ~/ipa-tmp
# cd ~/ipa-tmp

Use the skipcpio and `cpio commands to extract the ramdisk to the temporary directory:

# /usr/lib/dracut/skipcpio ~/images/ironic-python-agent.initramfs | zcat | cpio -ivd | pax -r

Install an RPM package to the extracted contents:

# rpm2cpio ~/RPMs/python-proliantutils-2.1.7-1.el7ost.noarch.rpm | pax -r

Recreate the new ramdisk:

# find . 2>/dev/null | cpio --quiet -c -o | gzip -8  > /home/stack/images/ironic-python-agent.initramfs
# chown stack: /home/stack/images/ironic-python-agent.initramfs

Verify the new package now exists in the ramdisk:

# lsinitrd /home/stack/images/ironic-python-agent.initramfs | grep proliant

The libguestfs-tools package contains the virt-customize tool. Install the libguestfs-tools from the rhel-8-for-x86_64-appstream-eus-rpms repository:

$ sudo dnf install libguestfs-tools

$ sudo systemctl disable --now iscsid.socket

Before you can review the contents of the overcloud-full.qcow2 image, you must create a virtual machine that uses this image.

To create a virtual machine instance that uses the overcloud-full.qcow2 image, enter the guestmount command:

$ mkdir ~/overcloud-full
$ guestmount -a overcloud-full.qcow2 -i --ro ~/overcloud-full

You can review the contents of the QCOW2 image in ~/overcloud-full.

Alternatively, you can use virt-manager to create a virtual machine with the following boot options:

Set the password for the root user on image:

$ virt-customize --selinux-relabel -a overcloud-full.qcow2 --root-password password:test
[  0.0] Examining the guest ...
[ 18.0] Setting a random seed
[ 18.0] Setting passwords
[ 19.0] Finishing off

This provides administration-level access for your nodes through the console.

Register your image temporarily to enable Red Hat repositories relevant to your customizations:

$ virt-customize --selinux-relabel -a overcloud-full.qcow2 --run-command 'subscription-manager register --username=[username] --password=[password]'
[  0.0] Examining the guest ...
[ 10.0] Setting a random seed
[ 10.0] Running: subscription-manager register --username=[username] --password=[password]
[ 24.0] Finishing off

Make sure to replace the [username] and [password] with your Red Hat customer account details. This runs the following command on the image:

subscription-manager register --username=[username] --password=[password]

This registers your Overcloud image to the Red Hat Content Delivery Network:

Find a list of pool ID from your account’s subscriptions:

$ sudo subscription-manager list

Choose a subscription pool ID and attach it to the image:

$ virt-customize --selinux-relabel -a overcloud-full.qcow2 --run-command 'subscription-manager attach --pool [subscription-pool]'
[  0.0] Examining the guest ...
[ 12.0] Setting a random seed
[ 12.0] Running: subscription-manager attach --pool [subscription-pool]
[ 52.0] Finishing off

Make sure to replace the [subscription-pool] with your chosen subscription pool ID. This runs the following command on the image:

subscription-manager attach --pool [subscription-pool]

This adds the pool to the image, which allows you to enable Red Hat repositories with the following command:

$ subscription-manager repos --enable=[repo-id]

Adding third-party software to the image requires additional repositories. For example, the following is an example repo file that contains configuration to use the OpenDaylight repository content:

$ cat opendaylight.repo

[opendaylight]
name=OpenDaylight Repository
baseurl=https://nexus.opendaylight.org/content/repositories/opendaylight-yum-epel-8-x86_64/
gpgcheck=0

Copy the repository file on to the image:

$ virt-customize --selinux-relabel -a overcloud-full.qcow2 --upload opendaylight.repo:/etc/yum.repos.d/
[  0.0] Examining the guest ...
[ 12.0] Setting a random seed
[ 12.0] Copying: opendaylight.repo to /etc/yum.repos.d/
[ 13.0] Finishing off

The --copy-in option copies the repository file to /etc/yum.repos.d/ on the Overcloud image.

Important: Red Hat does not offer support for software from non-certified vendors. Check with your Red Hat support representative that the software you aim to install is supported.

Use the virt-customize command to install packages to the image:

$ virt-customize --selinux-relabel -a overcloud-full.qcow2 --install opendaylight
[  0.0] Examining the guest ...
[ 11.0] Setting a random seed
[ 11.0] Installing packages: opendaylight
[ 91.0] Finishing off

The --install option allows you to specify a package to install.

After installing the necessary packages to customize the image, we now remove our subscriptions and unregister the image:

$ virt-customize --selinux-relabel -a overcloud-full.qcow2 --run-command 'subscription-manager remove --all'
[  0.0] Examining the guest ...
[ 12.0] Setting a random seed
[ 12.0] Running: subscription-manager remove --all
[ 18.0] Finishing off

This removes all subscription pools from the image.

Unregister the image. This is so the Overcloud deployment process can deploy the image to your nodes and register each of them individually.

$ virt-customize --selinux-relabel -a overcloud-full.qcow2 --run-command 'subscription-manager unregister'
[  0.0] Examining the guest ...
[ 11.0] Setting a random seed
[ 11.0] Running: subscription-manager unregister
[ 17.0] Finishing off

Reset the machine ID for the image. This ensures machines using this image do not use duplicate machine IDs.

$ virt-sysprep --operation machine-id -a overcloud-full.qcow2

After modifying the image, upload it to the director. Make sure to source the stackrc file so that you can access the director from the command line:

$ source stackrc
$ openstack overcloud image upload --image-path /home/stack/images/

This uploads the following images into the director: bm-deploy-kernel, bm-deploy-ramdisk, overcloud-full, overcloud-full-initrd, and overcloud-full-vmlinuz. These are the images for deployment and the Overcloud. The script also installs the introspection images on the director’s PXE server. View a list of the images in the CLI using the following command:

$ openstack image list
+--------------------------------------+------------------------+
| ID                                   | Name                   |
+--------------------------------------+------------------------+
| 765a46af-4417-4592-91e5-a300ead3faf6 | bm-deploy-ramdisk      |
| 09b40e3d-0382-4925-a356-3a4b4f36b514 | bm-deploy-kernel       |
| ef793cd0-e65c-456a-a675-63cd57610bd5 | overcloud-full         |
| 9a51a6cb-4670-40de-b64b-b70f4dd44152 | overcloud-full-initrd  |
| 4f7e33f4-d617-47c1-b36f-cbe90f132e5d | overcloud-full-vmlinuz |
+--------------------------------------+------------------------+

This list will not show the introspection PXE images (agent.*). The director copies these files to /httpboot.

[stack@host1 ~]$ ls /httpboot -l
total 151636
-rw-r--r--. 1 ironic ironic       269 Sep 19 02:43 boot.ipxe
-rw-r--r--. 1 root   root         252 Sep 10 15:35 inspector.ipxe
-rwxr-xr-x. 1 root   root     5027584 Sep 10 16:32 agent.kernel
-rw-r--r--. 1 root   root   150230861 Sep 10 16:32 agent.ramdisk
drwxr-xr-x. 2 ironic ironic      4096 Sep 19 02:45 pxelinux.cfg