Red Hat Training

A Red Hat training course is available for Red Hat OpenStack Platform

1.2. Managing images

The OpenStack Image service (glance) provides discovery, registration, and delivery services for disk and server images. It provides the ability to copy or snapshot a server image, and immediately store it. You can use stored images as a template to get new servers up and running quickly and more consistently than installing a server operating system and individually configuring services.

1.2.1. Creating an image

Manually create Red Hat OpenStack Platform (RHOSP) compatible images in the QCOW2 format by using Red Hat Enterprise Linux 7 ISO files, Red Hat Enterprise Linux 6 ISO files, or Windows ISO files.

1.2.1.1. Using a KVM guest image with Red Hat OpenStack Platform

You can use a ready RHEL KVM guest QCOW2 image:

These images are configured with cloud-init and must take advantage of ec2-compatible metadata services for provisioning SSH keys to function properly.

Ready Windows KVM guest QCOW2 images are not available.

注記

For the KVM guest images:

  • The root account in the image is disabled, but sudo access is granted to a special user named cloud-user.
  • There is no root password set for this image.

The root password is locked in /etc/shadow by placing !! in the second field.

For a RHOSP instance, it is recommended that you generate an ssh keypair from the RHOSP dashboard or command line and use that key combination to perform an SSH public authentication to the instance as root.

When the instance is launched, this public key is injected to it. You can then use the private key you downloaded while you created the keypair to authenticate.

If you do not want to use keypairs, you can use the admin password that you can set in the procedure to inject an admin password, see Injecting an admin password into an instance.

If you want to create custom Red Hat Enterprise Linux or Windows images, see:

1.2.1.2. Creating custom Red Hat Enterprise Linux or Windows images

Prerequisites

  • Linux host machine to create an image. This can be any machine on which you can install and run the Linux packages.
  • libvirt, virt-manager (run command yum groupinstall -y @virtualization). This installs all packages necessary to create a guest operating system.
  • Libguestfs tools (run command yum install -y libguestfs-tools-c). This installs a set of tools to access and modify virtual machine images.
  • A Red Hat Enterprise Linux 7 or 6 ISO file (see RHEL 7.2 Binary DVD or RHEL 6.8 Binary DVD) or a Windows ISO file. If you do not have a Windows ISO file, visit the Microsoft TechNet Evaluation Center and download an evaluation image.
  • A text editor if you want to change the kickstart files (RHEL only).
重要

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: 

$ sudo systemctl disable --now iscsid.socket
注記

In the following procedures, you must run all commands with the [root@host]# prompt on your host machine.

1.2.1.2.1. Creating a Red Hat Enterprise Linux 7 image

Manually create a Red Hat OpenStack Platform (RHOSP) compatible image in the QCOW2 format by using a Red Hat Enterprise Linux 7 ISO file.

Procedure

  1. Start the installation using virt-install: 

    [root@host]# qemu-img create -f qcow2 rhel7.qcow2 8G
[root@host]# virt-install --virt-type kvm --name rhel7 --ram 2048 \
--cdrom /tmp/rhel-server-7.2-x86_64-dvd.iso \
--disk rhel7.qcow2,format=qcow2 \
--network=bridge:virbr0 --graphics vnc,listen=0.0.0.0 \
--noautoconsole --os-type=linux --os-variant=rhel7

    This launches an instance and starts the installation process.

    注記

    If the instance does not launch automatically, run the virt-viewer command to view the console: 

    [root@host]# virt-viewer rhel7

  2. Configure the virtual machine as follows:

    1. At the initial Installer boot menu, choose the Install Red Hat Enterprise Linux 7.X option.
    2. Choose the appropriate Language and Keyboard options.
    3. When prompted about which type of devices your installation uses, choose Auto-detected installation media.
    4. When prompted about which type of installation destination, choose Local Standard Disks. For other storage options, choose Automatically configure partitioning.
    5. For software selection, choose Minimal Install.
    6. For network and host name, choose eth0 for network and choose a hostname for your device. The default host name is localhost.localdomain.
    7. Choose the root password. The installation process completes and the Complete! screen appears.
  3. After the installation is complete, reboot the instance and log in as the root user.

  4. Update the /etc/sysconfig/network-scripts/ifcfg-eth0 file so that it contains only the following values: 

    TYPE=Ethernet
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=dhcp
NM_CONTROLLED=no
  5. Reboot the machine.

  6. Register the machine with the Content Delivery Network. 

    # sudo subscription-manager register
# sudo subscription-manager attach --pool=Valid-Pool-Number-123456
# sudo subscription-manager repos --enable=rhel-7-server-rpms

  7. Update the system: 

    # yum -y update

  8. Install the cloud-init packages: 

    # yum install -y cloud-utils-growpart cloud-init

  9. Edit the /etc/cloud/cloud.cfg configuration file and under cloud_init_modules add: 

    - resolv-conf

    The resolv-conf option automatically configures the resolv.conf when an instance boots for the first time. This file contains information related to the instance such as nameservers, domain and other options.

  10. Add the following line to /etc/sysconfig/network to avoid problems accessing the EC2 metadata service: 

    NOZEROCONF=yes

  11. To ensure the console messages appear in the Log tab on the dashboard and the nova console-log output, add the following boot option to the /etc/default/grub file: 

    GRUB_CMDLINE_LINUX_DEFAULT="console=tty0 console=ttyS0,115200n8"

    Run the grub2-mkconfig command: 

    # grub2-mkconfig -o /boot/grub2/grub.cfg

    The output is as follows: 

    Generating grub configuration file ...
Found linux image: /boot/vmlinuz-3.10.0-229.7.2.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-229.7.2.el7.x86_64.img
Found linux image: /boot/vmlinuz-3.10.0-121.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-121.el7.x86_64.img
Found linux image: /boot/vmlinuz-0-rescue-b82a3044fb384a3f9aeacf883474428b
Found initrd image: /boot/initramfs-0-rescue-b82a3044fb384a3f9aeacf883474428b.img
done

  12. Un-register the virtual machine so that the resulting image does not contain the same subscription details for every instance cloned based on it: 

    # subscription-manager repos --disable=*
# subscription-manager unregister
# yum clean all

  13. Power off the instance: 

    # poweroff

  14. Use the virt-sysprep command to reset and clean the image so that it can be used to create instances without issues: 

    [root@host]# virt-sysprep -d rhel7

  15. Reduce image size by using the virt-sparsify command. This command converts any free space within the disk image back to free space within the host: 

    [root@host]# virt-sparsify --compress /tmp/rhel7.qcow2 rhel7-cloud.qcow2

    This creates a new rhel7-cloud.qcow2 file in the location from where the command is run.

The rhel7-cloud.qcow2 image file is ready to be uploaded to the Image service. For more information about using the dashboard to upload this image to your RHOSP deployment, see Upload an Image.

1.2.1.2.2. Creating a Red Hat Enterprise Linux 6 image

Manually create a Red Hat OpenStack Platform (RHOSP) compatible image in the QCOW2 format by using a Red Hat Enterprise Linux 6 ISO file.

Procedure

  1. Use virt-install to start the installation: 

    [root@host]# qemu-img create -f qcow2 rhel6.qcow2 4G
[root@host]# virt-install --connect=qemu:///system --network=bridge:virbr0 \
--name=rhel6 --os-type linux --os-variant rhel6 \
--disk path=rhel6.qcow2,format=qcow2,size=10,cache=none \
--ram 4096 --vcpus=2 --check-cpu --accelerate \
--hvm --cdrom=rhel-server-6.8-x86_64-dvd.iso

    This launches an instance and starts the installation process.

    注記

    If the instance does not launch automatically, run the virt-viewer command to view the console: 

    [root@host]# virt-viewer rhel6

  2. Configure the virtual machines as follows:

    1. At the initial Installer boot menu, choose the Install or upgrade an existing system option. Follow the installation prompts. Accept the defaults.

      The installer checks for the disc and lets you decide whether you want to test your installation media before installation. Select OK to run the test or Skip to proceed without testing.

    2. Choose the appropriate Language and Keyboard options.
    3. When prompted about which type of devices your installation uses, choose Basic Storage Devices.
    4. Choose a hostname for your device. The default host name is localhost.localdomain.
    5. Set timezone and root password.
    6. Based on the space on the disk, choose the type of installation.
    7. Choose the Basic Server install, which installs an SSH server.
    8. The installation process completes and Congratulations, your Red Hat Enterprise Linux installation is complete screen appears.
  3. Reboot the instance and log in as the root user.

  4. Update the /etc/sysconfig/network-scripts/ifcfg-eth0 file so it only contains the following values: 

    TYPE=Ethernet
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=dhcp
NM_CONTROLLED=no
  5. Reboot the machine.

  6. Register the machine with the Content Delivery Network: 

    # sudo subscription-manager register
# sudo subscription-manager attach --pool=Valid-Pool-Number-123456
# sudo subscription-manager repos --enable=rhel-6-server-rpms

  7. Update the system: 

    # yum -y update

  8. Install the cloud-init packages: 

    # yum install -y cloud-utils-growpart cloud-init

  9. Edit the /etc/cloud/cloud.cfg configuration file and under cloud_init_modules add: 

    - resolv-conf

    The resolv-conf option automatically configures the resolv.conf configuration file when an instance boots for the first time. This file contains information related to the instance such as nameservers, domain, and other options.

  10. To prevent network issues, create the /etc/udev/rules.d/75-persistent-net-generator.rules file as follows: 

    # echo "#" > /etc/udev/rules.d/75-persistent-net-generator.rules

    This prevents /etc/udev/rules.d/70-persistent-net.rules file from being created. If /etc/udev/rules.d/70-persistent-net.rules is created, networking might not function correctly when booting from snapshots (the network interface is created as eth1 rather than eth0 and IP address is not assigned).

  11. Add the following line to /etc/sysconfig/network to avoid problems accessing the EC2 metadata service: 

    NOZEROCONF=yes

  12. To ensure the console messages appear in the Log tab on the dashboard and the nova console-log output, add the following boot option to the /etc/grub.conf: 

    console=tty0 console=ttyS0,115200n8

  13. Un-register the virtual machine so that the resulting image does not contain the same subscription details for every instance cloned based on it: 

    # subscription-manager repos --disable=*
# subscription-manager unregister
# yum clean all

  14. Power off the instance: 

    # poweroff

  15. Use the virt-sysprep command to reset and clean the image so that it can be used to create instances without issues: 

    [root@host]# virt-sysprep -d rhel6

  16. Reduce image size by using the virt-sparsify command. This command converts any free space within the disk image back to free space within the host: 

    [root@host]# virt-sparsify --compress rhel6.qcow2 rhel6-cloud.qcow2

    This creates a new rhel6-cloud.qcow2 file in the location from where the command is run.

    注記

    You must manually resize the partitions of instances based on the image in accordance with the disk space in the flavor that is applied to the instance.

The rhel6-cloud.qcow2 image file is ready to upload to the Image service. For more information about using the dashboard to upload this image to your RHOSP deployment, see Upload an Image

1.2.1.2.3. Creating a Windows image

Manually create a Red Hat OpenStack Platform (RHOSP) compatible image in the QCOW2 format by using a Windows ISO file.

Procedure

  1. Use virt-install to start the installation: 

    [root@host]# virt-install --name=<name> \
--disk size=<size> \
--cdrom=<path>` \
--os-type=windows \
--network=bridge:virbr0 \
--graphics spice \
--ram=<RAM>

    Replace the values of the virt-install parameters as follows:

    • <name> — the name of the Windows guest.
    • <size> — disk size in GB.
    • <path> — the path to the Windows installation ISO file.

    • <RAM> — the requested amount of RAM in MB.

      注記

      The --os-type=windows parameter ensures that the clock is configured correctly for the Windows guest, and enables its Hyper-V enlightenment features.

      virt-install saves the guest image as /var/lib/libvirt/images/<name>.qcow2 by default. If you want to keep the guest image elsewhere, change the parameter of the --disk option as follows: 

      --disk path=<filename>,size=<size>

      Replace <filename> with the name of the file that stores the guest image, and optionally its path, for example, path=win8.qcow2,size=8 creates an 8 GB file named win8.qcow2 in the current working directory.

      ヒント

      If the guest does not launch automatically, run the virt-viewer command to view the console: 

      [root@host]# virt-viewer <name>
  2. Installation of Windows systems is beyond the scope of this document. For instructions about how to install Windows, see the relevant Microsoft documentation.
  3. To allow the newly installed Windows system to use the virtualized hardware, you might need to install virtio drivers in it. To so do, first install the virtio-win package on the host system. This package contains the virtio ISO image, which you must attach as a CD-ROM drive to the Windows guest. See Chapter 8. KVM Para-virtualized (virtio) Drivers in the Virtualization Deployment and Administration Guide for detailed instructions on how to install the virtio-win package, add the virtio ISO image to the guest, and install the virtio drivers.

  4. To complete the configuration, download and execute Cloudbase-Init on the Windows system. At the end of the installation of Cloudbase-Init, select the Run Sysprep and Shutdown check boxes. The Sysprep tool makes the guest unique by generating an OS ID, which certain Microsoft services use.

    重要

    Red Hat does not provide technical support for Cloudbase-Init. If you encounter an issue, contact Cloudbase Solutions.

When the Windows system shuts down, the <name>_.qcow2 image file is ready to upload to the Image service. For more information about using the dashboard or the command line to upload this image to your RHOSP deployment, see Uploading an Image.

注記

libosinfo data

The Compute service has deprecated support for using libosinfo data to set default device models. Instead, use the following image metadata properties to configure the optimal virtual hardware for an instance:

  • os_distro
  • os_version
  • hw_cdrom_bus
  • hw_disk_bus
  • hw_scsi_model
  • hw_vif_model
  • hw_video_model
  • hypervisor_type

For more information about these metadata properties, see 付録A Image configuration parameters.