Chapter 1. Image service

Manage images and storage in Red Hat OpenStack Platform (RHOSP).

A virtual machine image is a file that contains a virtual disk with a bootable operating system installed. Virtual machine images are supported in different formats. The following formats are available in RHOSP:

  • RAW - Unstructured disk image format.
  • QCOW2 - Disk format supported by QEMU emulator. This format includes QCOW2v3 (sometimes referred to as QCOW3), which requires QEMU 1.1 or higher.
  • ISO - Sector-by-sector copy of the data on a disk, stored in a binary file.
  • AKI - Indicates an Amazon Kernel Image.
  • AMI - Indicates an Amazon Machine Image.
  • ARI - Indicates an Amazon RAMDisk Image.
  • VDI - Disk format supported by VirtualBox virtual machine monitor and the QEMU emulator.
  • VHD - Common disk format used by virtual machine monitors from VMware, VirtualBox, and others.
  • VMDK - Disk format supported by many common virtual machine monitors.
  • PLOOP - A disk format supported and used by Virtuozzo to run OS containers.
  • OVA - Indicates that what is stored in the Image service (glance) is an OVA tar archive file.
  • DOCKER - Indicates that what is stored in the Image service (glance) is a Docker tar archive of the container file system.

Although ISO is not normally considered a virtual machine image format, because ISOs contain bootable filesystems with an installed operating system, you use them in the same way as other virtual machine image files.

To download the official Red Hat Enterprise Linux cloud images, your account must have a valid Red Hat Enterprise Linux subscription:

If you are not logged in to the Customer Portal, a prompt opens where you must enter your Red Hat account credentials.

1.1. Understanding the Image service

Red Hat OpenStack Platform (RHOSP) Image service (glance) features.

1.1.1. Supported Image service (glance) back ends

The following Image service (glance) back end scenarios are supported:

  • RBD is the default back end when you use Ceph. For more information, see Configuring Ceph Storage in the Advanced Overcloud Customization guide.
  • RBD multi-store. For more information, see Deploying the central site in the Distributed compute node and storage deployment guide.
  • Object Storage (swift). For more information, see Using an External Object Storage Cluster in the Advanced Overcloud Customization guide.
  • Block Storage (cinder). For more information, see Configuring cinder back end for the Image service in the Advanced Overcloud Customization guide.

    The Image service uses the Block Storage type and back end as the default.

  • NFS. For more information, see Configuring NFS Storage in the Advanced Overcloud Customization guide.

    Important

    Although NFS is a supported Image service deployment option, more robust options are available.

    NFS is not native to the Image service. When you mount an NFS share on the Image service, the Image service does not manage the operation. The Image service writes data to the file system but is unaware that the back end is an NFS share.

    In this type of deployment, the Image service cannot retry a request if the share fails. This means that when a failure occurs on the back end, the store might enter read-only mode, or it might continue to write data to the local file system, in which case you risk data loss. To recover from this situation, you must ensure that the share is mounted and in sync, and then restart the Image service. For these reasons, Red Hat does not recommend NFS as an Image service back end.

    However, if you do choose to use NFS as an Image service back end, some of the following best practices can help to mitigate risks:

    • Use a reliable production-grade NFS back end.
    • Ensure that you have a strong and reliable connection between Controller nodes and the NFS back end, L2 is recommended.
    • Include monitoring and alerts for the mounted share.
    • Set underlying FS permissions.

      • Ensure that the user and the group that the glance-api process runs on do not have write permissions on the mount point at the local file system. This means that the process can detect possible mount failure and put the store into read-only mode during a write attempt.
      • The write permissions must be present in the shared file system that you use as a store.

1.1.2. Image signing and verification

Image signing and verification protects image integrity and authenticity by enabling deployers to sign images and save the signatures and public key certificates as image properties.

By taking advantage of this feature, you can:

  • Sign an image using your private key and upload the image, the signature, and a reference to your public key certificate (the verification metadata). The Image service then verifies that the signature is valid.
  • Create an image in the Compute service, have the Compute service sign the image, and upload the image and its verification metadata. The Image service again verifies that the signature is valid.
  • Request a signed image in the Compute service. The Image service provides the image and its verification metadata, allowing the Compute service to validate the image before booting it.

For information on image signing and verification, refer to the Validate Glance Images chapter of the Manage Secrets with OpenStack Key Manager Guide.

1.1.3. Image conversion

Image conversion converts images by calling the task API while importing an image.

As part of the import workflow, a plugin provides the image conversion. This plugin can be activated or deactivated based on the deployer configuration. Therefore, the deployer needs to specify the preferred format of images for the deployment.

Internally, the Image service receives the bits of the image in a particular format. These bits are stored in a temporary location. The plugin is then triggered to convert the image to the target format and moved to a final destination. When the task is finished, the temporary location is deleted. As a result, the format uploaded initially is not retained by the Image service.

For more information about image conversion, see Enabling image conversion.

Note

The conversion can be triggered only when importing an image. It does not run when uploading an image. For example:

$ glance image-create-via-import \
    --disk-format qcow2 \
    --container-format bare \
    --name NAME \
    --visibility public \
    --import-method web-download \
    --uri http://server/image.qcow2

1.1.4. Image introspection

Every image format comes with a set of metadata embedded inside the image itself. For example, a stream optimized vmdk would contain the following parameters:

$ head -20 so-disk.vmdk

# Disk DescriptorFile
version=1
CID=d5a0bce5
parentCID=ffffffff
createType="streamOptimized"

# Extent description
RDONLY 209714 SPARSE "generated-stream.vmdk"

# The Disk Data Base
#DDB

ddb.adapterType = "buslogic"
ddb.geometry.cylinders = "102"
ddb.geometry.heads = "64"
ddb.geometry.sectors = "32"
ddb.virtualHWVersion = "4"

By introspecting this vmdk, you can easily know that the disk_type is streamOptimized, and the adapter_type is buslogic. These metadata parameters are useful for the consumer of the image. In Compute, the workflow to instantiate a streamOptimized disk is different from the one to instantiate a flat disk. This new feature allows metadata extraction. You can achieve image introspection by calling the task API while importing the image. An administrator can override metadata settings.

1.1.5. Interoperable image import

The interoperable image import workflow enables you to import images in two ways:

  • Use the web-download (default) method to import images from a URI.
  • Use the glance-direct method to import images from a local file system.

1.1.6. Improving scalability with Image service caching

Use the glance-api caching mechanism to store copies of images on Image service (glance) API servers and retrieve them automatically to improve scalability. With Image service caching, glance-api can run on multiple hosts. This means that it does not need to retrieve the same image from back end storage multiple times. Image service caching does not affect any Image service operations.

Configure Image service caching with the Red Hat OpenStack Platform director (tripleo) heat templates:

Procedure

  1. In an environment file, set the value of the GlanceCacheEnabled parameter to true, which automatically sets the flavor value to keystone+cachemanagement in the glance-api.conf heat template:

    parameter_defaults:
        GlanceCacheEnabled: true
  2. Include the environment file in the openstack overcloud deploy command when you redeploy the overcloud.
  3. Optional: Tune the glance_cache_pruner to an alternative frequency when you redeploy the overcloud. The following example shows a frequency of 5 minutes:

    parameter_defaults:
      ControllerExtraConfig:
        glance::cache::pruner::minute: '*/5'

    Adjust the frequency according to your needs to avoid file system full scenarios. Include the following elements when you choose an alternative frequency:

    • The size of the files that you want to cache in your environment.
    • The amount of available file system space.
    • The frequency at which the environment caches images.

1.1.7. Image pre-caching

This feature is available in this release as 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.

1.1.7.1. Configuring the default interval for periodic image pre-caching

Red Hat OpenStack Platform (RHOSP) director can pre-cache images as part of the glance-api service. The default periodic interval is 300 seconds. You can increase or decrease the default interval based on your requirements.

Procedure

  1. Add a new interval with the ExtraConfig parameter in an environment file on the undercloud according to your requirements:

    parameter_defaults:
      ControllerExtraConfig:
        glance::config::glance_api_config:
          DEFAULT/cache_prefetcher_interval:
            value: '<300>'

    Replace <300> with the number of seconds that you want as an interval to pre-cache images.

  2. After you adjust the interval in the environment file in /home/stack/templates/, log in as the stack user and deploy the configuration:

    $ openstack overcloud deploy --templates \
    -e /home/stack/templates/<ENV_FILE>.yaml

    Replace <ENV_FILE> with the name of the environment file that contains the ExtraConfig settings that you added.

Important

If you passed any extra environment files when you created the overcloud, pass them again here by using the -e option to avoid making undesired changes to the overcloud.

For more information about the openstack overcloud deploy command, see Deployment command in the Director Installation and Usage guide.

1.1.7.2. Using a periodic job to pre-cache an image

Prerequisites

To use a periodic job to pre-cache an image, you must use the glance-cache-manage command connected directly to the node where the glance_api service is running. Do not use a proxy, which hides the node that answers a service request. Because the undercloud might not have access to the network where the glance_api service is running, run commands on the first overcloud node, which is called controller-0 by default.

Complete the following prerequisite procedure to ensure that you run commands from the correct host, have the necessary credentials, and are also running the glance-cache-manage commands from inside the glance-api container.

Procedure

  1. Log in to the undercloud as the stack user and identify the provisioning IP address of controller-0:

    (undercloud) [stack@site-undercloud-0 ~]$ openstack server list -f value -c Name -c Networks | grep controller
    overcloud-controller-1 ctlplane=192.168.24.40
    overcloud-controller-2 ctlplane=192.168.24.13
    overcloud-controller-0 ctlplane=192.168.24.71
    (undercloud) [stack@site-undercloud-0 ~]$
  2. To authenticate to the overcloud, copy the credentials that are stored in /home/stack/overcloudrc, by default, to controller-0:

    $ scp ~/overcloudrc heat-admin@192.168.24.71:/home/heat-admin/
  3. Connect to controller-0:

    $ ssh heat-admin@192.168.24.71
  4. On controller-0 as the heat-admin user, identify the IP address of the glance_api service. In the following example, the IP address is 172.25.1.105:

    (overcloud) [root@controller-0 ~]# grep -A 10 '^listen glance_api' 1/var/lib/config-data/puppet-generated/haproxy/etc/haproxy/haproxy.cfg
    listen glance_api
     server central-controller0-0.internalapi.redhat.local 172.25.1.105:9292 check fall 5 inter 2000 rise 2
  5. Because the glance-cache-manage command is only available in the glance_api container, create a script to exec into that container where the environment variables to authenticate to the overcloud are already set. Create a script called glance_pod.sh in /home/heat-admin on controller-0 with the following contents:

    sudo podman exec -ti \
     -e NOVA_VERSION=$NOVA_VERSION \
     -e COMPUTE_API_VERSION=$COMPUTE_API_VERSION \
     -e OS_USERNAME=$OS_USERNAME \
     -e OS_PROJECT_NAME=$OS_PROJECT_NAME \
     -e OS_USER_DOMAIN_NAME=$OS_USER_DOMAIN_NAME \
     -e OS_PROJECT_DOMAIN_NAME=$OS_PROJECT_DOMAIN_NAME \
     -e OS_NO_CACHE=$OS_NO_CACHE \
     -e OS_CLOUDNAME=$OS_CLOUDNAME \
     -e no_proxy=$no_proxy \
     -e OS_AUTH_TYPE=$OS_AUTH_TYPE \
     -e OS_PASSWORD=$OS_PASSWORD \
     -e OS_AUTH_URL=$OS_AUTH_URL \
     -e OS_IDENTITY_API_VERSION=$OS_IDENTITY_API_VERSION \
     -e OS_COMPUTE_API_VERSION=$OS_COMPUTE_API_VERSION \
     -e OS_IMAGE_API_VERSION=$OS_IMAGE_API_VERSION \
     -e OS_VOLUME_API_VERSION=$OS_VOLUME_API_VERSION \
     -e OS_REGION_NAME=$OS_REGION_NAME \
    glance_api /bin/bash
  6. Source the overcloudrc file and run the glance_pod.sh script to exec into the glance_api container with the necessary environment variables to authenticate to the overcloud Controller node.

    [heat-admin@controller-0 ~]$ source overcloudrc
    (overcloudrc) [heat-admin@central-controller-0 ~]$ bash glance_pod.sh
    ()[glance@controller-0 /]$
  7. Use a command such as glance image-list to verify that the container can run authenticated commands against the overcloud.

    ()[glance@controller-0 /]$ glance image-list
    +--------------------------------------+----------------------------------+
    | ID                                   | Name                             |
    +--------------------------------------+----------------------------------+
    | ad2f8daf-56f3-4e10-b5dc-d28d3a81f659 | cirros-0.4.0-x86_64-disk.img       |
    +--------------------------------------+----------------------------------+
    ()[glance@controller-0 /]$

Procedure

  1. As the admin user, queue an image to cache:

    $ glance-cache-manage --host=<host_ip> queue-image <image_id>
    • Replace <host_ip> with the IP address of the Controller node where the glance-api container is running.
    • Replace <image_id> with the ID of the image that you want to queue.

      When you have queued the images that you want to pre-cache, the cache_images periodic job prefetches all queued images concurrently.

      Note

      Because the image cache is local to each node, if your Red Hat OpenStack Platform is deployed with HA (with 3, 5, or 7 Controllers) then you must specify the host address with the --host option when you run the glance-cache-manage command.

  2. Run the following command to view the images in the image cache:

    $ glance-cache-manage --host=<host_ip> list-cached

    Replace <host_ip> with the IP address of the host in your environment.

Related information

You can use additional glance-cache-manage commands for the following purposes:

  • list-cached to list all images that are currently cached.
  • list-queued to list all images that are currently queued for caching.
  • queue-image to queue an image for caching.
  • delete-cached-image to purge an image from the cache.
  • delete-all-cached-images to remove all images from the cache.
  • delete-queued-image to delete an image from the cache queue.
  • delete-all-queued-images to delete all images from the cache queue.

1.1.8. Secure metadef APIs

In Red Hat OpenStack Platform (RHOSP), users can define key value pairs and tag metadata with metadata definition (metadef) APIs. Currently, there is no limit on the number of metadef namespaces, objects, properties, resources, or tags that users can create.

Metadef APIs can leak information to unauthorized users. A malicious user can exploit the lack of restrictions and fill the Image service (glance) database with unlimited resources, which can create a Denial of Service (DoS) style attack.

Image service policies control metadef APIs. However, the default policy setting for metadef APIs allows all users to create or read the metadef information. Because metadef resources are not isolated to the owner, metadef resources with potentially sensitive names, such as internal infrastructure details or customer names, can expose that information to malicious users.

1.1.8.1. Configuring a policy to restrict metadef APIs

To make the Image service (glance) more secure, restrict metadef modification APIs to admin-only access by default in your Red Hat OpenStack Platform (RHOSP) deployments.

Procedure

  1. As a cloud administrator, create a separate heat template environment file, such as lock-down-glance-metadef-api.yaml, to contain policy overrides for the Image service metadef API:

    ...
    parameter_defaults:
      GlanceApiPolicies: {
    	glance-metadef_default: { key: 'metadef_default', value: '' },
    	glance-metadef_admin: { key: 'metadef_admin', value: 'role:admin' },
    	glance-get_metadef_namespace: { key: 'get_metadef_namespace', value: 'rule:metadef_default' },
    	glance-get_metadef_namespaces: { key: 'get_metadef_namespaces', value: 'rule:metadef_default' },
    	glance-modify_metadef_namespace: { key: 'modify_metadef_namespace', value: 'rule:metadef_admin' },
    	glance-add_metadef_namespace: { key: 'add_metadef_namespace', value: 'rule:metadef_admin' },
    	glance-delete_metadef_namespace: { key: 'delete_metadef_namespace', value: 'rule:metadef_admin' },
    	glance-get_metadef_object: { key: 'get_metadef_object', value: 'rule:metadef_default' },
    	glance-get_metadef_objects: { key: 'get_metadef_objects', value: 'rule:metadef_default' },
    	glance-modify_metadef_object: { key: 'modify_metadef_object', value: 'rule:metadef_admin' },
    	glance-add_metadef_object: { key: 'add_metadef_object', value: 'rule:metadef_admin' },
    	glance-delete_metadef_object: { key: 'delete_metadef_object', value: 'rule:metadef_admin' },
    	glance-list_metadef_resource_types: { key: 'list_metadef_resource_types', value: 'rule:metadef_default' },
    	glance-get_metadef_resource_type: { key: 'get_metadef_resource_type', value: 'rule:metadef_default' },
    	glance-add_metadef_resource_type_association: { key: 'add_metadef_resource_type_association', value: 'rule:metadef_admin' },
    	glance-remove_metadef_resource_type_association: { key: 'remove_metadef_resource_type_association', value: 'rule:metadef_admin' },
    	glance-get_metadef_property: { key: 'get_metadef_property', value: 'rule:metadef_default' },
    	glance-get_metadef_properties: { key: 'get_metadef_properties', value: 'rule:metadef_default' },
    	glance-modify_metadef_property: { key: 'modify_metadef_property', value: 'rule:metadef_admin' },
    	glance-add_metadef_property: { key: 'add_metadef_property', value: 'rule:metadef_admin' },
    	glance-remove_metadef_property: { key: 'remove_metadef_property', value: 'rule:metadef_admin' },
    	glance-get_metadef_tag: { key: 'get_metadef_tag', value: 'rule:metadef_default' },
    	glance-get_metadef_tags: { key: 'get_metadef_tags', value: 'rule:metadef_default' },
    	glance-modify_metadef_tag: { key: 'modify_metadef_tag', value: 'rule:metadef_admin' },
    	glance-add_metadef_tag: { key: 'add_metadef_tag', value: 'rule:metadef_admin' },
    	glance-add_metadef_tags: { key: 'add_metadef_tags', value: 'rule:metadef_admin' },
    	glance-delete_metadef_tag: { key: 'delete_metadef_tag', value: 'rule:metadef_admin' },
    	glance-delete_metadef_tags: { key: 'delete_metadef_tags', value: 'rule:metadef_admin' }
      }
    
    …
  2. Include the environment file that contains the policy overrides in the deployment command with the -e option when you deploy the overcloud:

    $ openstack overcloud deploy -e lock-down-glance-metadef-api.yaml

1.1.8.2. Enabling metadef APIs

If you previously restricted metadata definition (metadef) APIs or want to relax the new defaults, you can override metadef modification policies to allow users to update their respective resources.

Important

Cloud administrators with users who depend on write access to the metadef APIs can make those APIs accessible to all users. In this type of configuration, however, there is the potential to unintentionally leak sensitive resource names, such as customer names and internal projects. Administrators must audit their systems to identify previously created resources that might be vulnerable even if only read access is enabled for all users.

Procedure

  1. As a cloud administrator, log in to the undercloud and create a file for policy overrides. For example:

    $ cat open-up-glance-api-metadef.yaml
  2. Configure the policy override file to allow metadef API read-write access to all users:

    GlanceApiPolicies: {
        glance-metadef_default: { key: 'metadef_default', value: '' },
        glance-get_metadef_namespace: { key: 'get_metadef_namespace', value: 'rule:metadef_default' },
        glance-get_metadef_namespaces: { key: 'get_metadef_namespaces', value: 'rule:metadef_default' },
        glance-modify_metadef_namespace: { key: 'modify_metadef_namespace', value: 'rule:metadef_default' },
        glance-add_metadef_namespace: { key: 'add_metadef_namespace', value: 'rule:metadef_default' },
        glance-delete_metadef_namespace: { key: 'delete_metadef_namespace', value: 'rule:metadef_default' },
        glance-get_metadef_object: { key: 'get_metadef_object', value: 'rule:metadef_default' },
        glance-get_metadef_objects: { key: 'get_metadef_objects', value: 'rule:metadef_default' },
        glance-modify_metadef_object: { key: 'modify_metadef_object', value: 'rule:metadef_default' },
        glance-add_metadef_object: { key: 'add_metadef_object', value: 'rule:metadef_default' },
        glance-delete_metadef_object: { key: 'delete_metadef_object', value: 'rule:metadef_default' },
        glance-list_metadef_resource_types: { key: 'list_metadef_resource_types', value: 'rule:metadef_default' },
        glance-get_metadef_resource_type: { key: 'get_metadef_resource_type', value: 'rule:metadef_default' },
        glance-add_metadef_resource_type_association: { key: 'add_metadef_resource_type_association', value: 'rule:metadef_default' },
        glance-remove_metadef_resource_type_association: { key: 'remove_metadef_resource_type_association', value: 'rule:metadef_default' },
        glance-get_metadef_property: { key: 'get_metadef_property', value: 'rule:metadef_default' },
        glance-get_metadef_properties: { key: 'get_metadef_properties', value: 'rule:metadef_default' },
        glance-modify_metadef_property: { key: 'modify_metadef_property', value: 'rule:metadef_default' },
        glance-add_metadef_property: { key: 'add_metadef_property', value: 'rule:metadef_default' },
        glance-remove_metadef_property: { key: 'remove_metadef_property', value: 'rule:metadef_default' },
        glance-get_metadef_tag: { key: 'get_metadef_tag', value: 'rule:metadef_default' },
        glance-get_metadef_tags: { key: 'get_metadef_tags', value: 'rule:metadef_default' },
        glance-modify_metadef_tag: { key: 'modify_metadef_tag', value: 'rule:metadef_default' },
        glance-add_metadef_tag: { key: 'add_metadef_tag', value: 'rule:metadef_default' },
        glance-add_metadef_tags: { key: 'add_metadef_tags', value: 'rule:metadef_default' },
        glance-delete_metadef_tag: { key: 'delete_metadef_tag', value: 'rule:metadef_default' },
        glance-delete_metadef_tags: { key: 'delete_metadef_tags', value: 'rule:metadef_default' }
      }
    Note

    You must configure all metadef policies to use rule:metadeta_default.

  3. Include the new policy file in the deployment command with the -e option when you deploy the overcloud:

    $ openstack overcloud deploy -e open-up-glance-api-metadef.yaml

1.2. Manage images

The 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 commission new servers 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. Use 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 correctly.

Ready Windows KVM guest QCOW2 images are not available.

Note

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, 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 authenticate by using the private key that you download when you create the keypair.

If you do not want to use keypairs, you can use the admin password that has been set using the Inject an admin Password Into an Instance procedure.

If you want to create custom Red Hat Enterprise Linux or Windows images, see Create a Red Hat Enterprise Linux 7 Image, Create a Red Hat Enterprise Linux 6 Image, or Create a Windows Image.

1.2.1.2. Create 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 to install all packages necessary to create a guest operating system:

    $ sudo dnf groupinstall -y @virtualization
  • Libguestfs tools to install a set of tools to access and modify virtual machine images:

    $ sudo dnf install -y libguestfs-tools-c
  • A Red Hat Enterprise Linux 7 or 6 ISO file. For more information, 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, see Microsoft TechNet Evaluation Center to download an evaluation image.
  • Text editor, if you want to change the kickstart files (RHEL only).
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:

$ sudo systemctl disable --now iscsid.socket
1.2.1.2.1. Create 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.

Note

You must run all commands with the [root@host]# on your host machine.

  1. Start the installation by 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.

    Note

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

    [root@host]# virt-viewer rhel7
  2. Configure the instance:

    1. At the initial Installer boot menu, select Install Red Hat Enterprise Linux 7.
    2. Choose the appropriate Language and Keyboard options.
    3. When prompted about which type of devices your installation uses, select Auto-detected installation media.
    4. When prompted about which type of installation destination, select Local Standard Disks. For other storage options, select Automatically configure partitioning.
    5. For software selection, select Minimal Install.
    6. For network and host name, select eth0 for network and choose a host name for your device. The default host name is localhost.localdomain.
    7. Enter a password in the Root Password field and enter the same password again in the Confirm field.

      Result
      The installation process completes and the Complete! screen is displayed.
  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:

    # dnf -y update
  8. Install the cloud-init packages:

    # dnf 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 that 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"
  12. 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
  13. Deregister the instance so that the resulting image does not contain the subscription details for this instance:

    # subscription-manager repos --disable=*
    # subscription-manager unregister
    # dnf clean all
  14. Power off the instance:

    # poweroff
  15. Reset and clean the image by using the virt-sysprep command so that it can be used to create instances without issues:

    [root@host]# virt-sysprep -d rhel7
  16. Reduce the image size by converting 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 uploading this image to your RHOSP deployment by using the dashboard, see Upload an Image.

1.2.1.2.2. Create 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.

Note

You must run all commands with the [root@host]# on your host machine.

  1. Start the installation by using virt-install:

    [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.

    Note

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

    [root@host]# virt-viewer rhel6
  2. Configure the instances:

    1. At the initial Installer boot menu, select Install or upgrade an existing system and follow the installation prompts. Accept the defaults.

      The disk installer provides an option 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, select Basic Storage Devices.
    4. Choose a host name for your device. The default host name is localhost.localdomain.
    5. Set the timezone and root password.
    6. Based on the space on the disk, choose the type of installation you want from the options in the Which type of installation would you like? window.
    7. Choose the Basic Server install, which installs an SSH server.
    8. The installation process completes and the Congratulations, your Red Hat Enterprise Linux installation is complete screen is displayed.
  3. 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-6-server-rpms
  7. Update the system:

    # dnf -y update
  8. Install the cloud-init packages:

    # dnf install -y cloud-utils-growpart cloud-init
  9. Edit the /etc/cloud/cloud.cfg configuration file and add the following content under cloud_init_modules.

    - 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 /etc/udev/rules.d/75-persistent-net-generator.rules:

    # 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 you boot from snapshots, the network interface is created as eth1 rather than eth0 and the 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 that 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 file:

    console=tty0 console=ttyS0,115200n8
  13. Deregister the virtual machine so that the resulting image does not contain the same subscription details for this instance:

    # subscription-manager repos --disable=*
    # subscription-manager unregister
    # dnf clean all
  14. Power off the instance:

    # poweroff
  15. Reset and clean the image by using the virt-sysprep command 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.

    Note

    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 be uploaded to the Image service. For more information about uploading this image to your RHOSP deployment by using the dashboard, see Upload an Image

1.2.1.2.3. Create a Windows image

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

Note

You must run all commands with the [root@host]# on your host machine.

  1. Start the installation by using virt-install:

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

    Replace the following values of the virt-install parameters:

    • <name> — the name that the Windows instance has.
    • <size> — disk size in GB.
    • <path> — the path to the Windows installation ISO file.
    • <RAM> — the requested amount of RAM in MB.

      Note

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

  2. 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:

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

    Replace <filename> with the name of the file that stores the instance 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.

    Tip

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

    [root@host]# virt-viewer <name>

    For more information 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. To so do, first install the image, which you must attach as a CD-ROM drive to the Windows instance. To install the virtio-win package you must add the virtio ISO image to the instance, and install the virtio drivers. For more information, see Installing KVM paravirtualized drivers for Windows virtual machines in the Configuring and managing virtualization guide.
  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 checkboxes. The Sysprep tool makes the guest unique by generating an OS ID, which is used by certain Microsoft services.

    Important

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

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

Note

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 Appendix A, Image Configuration Parameters.

1.2.2. Upload an image

  1. In the dashboard, select Project > Compute > Images.
  2. Click Create Image.
  3. Fill out the values, and click Create Image.

Table 1.1. Image options

FieldNotes

Name

Name for the image. The name must be unique within the project.

Description

Brief description to identify the image.

Image Source

Image source: Image Location or Image File. Based on your selection, the next field is displayed.

Image Location or Image File

  • Select Image Location option to specify the image location URL.
  • Select Image File option to upload an image from the local disk.

Format

Image format (for example, qcow2).

Architecture

Image architecture. For example, use i686 for a 32-bit architecture or x86_64 for a 64-bit architecture.

Minimum Disk (GB)

Minimum disk size required to boot the image. If this field is not specified, the default value is 0 (no minimum).

Minimum RAM (MB)

Minimum memory size required to boot the image. If this field is not specified, the default value is 0 (no minimum).

Public

If selected, makes the image public to all users with access to the project.

Protected

If selected, ensures only users with specific permissions can delete this image.

When the image has been successfully uploaded, its status is active, which indicates that the image is available for use. Note that the Image service can handle even large images that take a long time to upload — longer than the lifetime of the Identity service token which was used when the upload was initiated. This is due to the fact that the Image service first creates a trust with the Identity service so that a new token can be obtained and used when the upload is complete and the status of the image is to be updated.

Note

You can also use the glance image-create command with the property option to upload an image. More values are available on the command line. For a complete listing, see Image Configuration Parameters.

1.2.3. Update an image

  1. In the dashboard, select Project > Compute > Images.
  2. Click Edit Image from the list.

    Note

    The Edit Image option is available only when you log in as an admin user. When you log in as a demo user, you have the option to Launch an instance or Create Volume.

  3. Update the fields and click Update Image . You can update the following values - name, description, kernel ID, ramdisk ID, architecture, format, minimum disk, minimum RAM, public, protected.
  4. Click the drop-down menu and select Update Metadata option.
  5. Specify metadata by adding items from the left column to the right one. In the left column, there are metadata definitions from the Image Service Metadata Catalog. Select Other to add metadata with the key of your choice and click Save when finished.
Note

You can also use the glance image-update command with the property option to update an image. More values are available on the command line; for a complete listing, see Image Configuration Parameters.

1.2.4. Import an image

You can import images into the Image service (glance) using web-download to import an image from a URI and glance-direct to import an image from a local file system. The web-download method is enabled by default.

Import methods are configured by the cloud administrator. Run the glance import-info command to list available import options.

1.2.4.1. Import from a remote URI

You can use the web-download method to copy an image from a remote URI.

  1. Create an image and specify the URI of the image to import.

    glance image-create --uri <URI>
  2. You can monitor the image availability by using the glance image-show <image_id> command. Replace <image_id> with the ID you provided during image creation.

The Image service web download method uses a two-stage process to perform the import. First, it creates an image record. Second, it retrieves the image the specified URI. This method provides a more secure way to import images than the deprecated copy-from method used in Image API v1.

The URI is subject to optional denylist and allowlist filtering as described in the Advanced Overcloud Customization guide.

The Image Property Injection plugin may inject metadata properties to the image as described in the Advanced Overcloud Customization guide. These injected properties determine which compute nodes the image instances are launched on.

1.2.4.2. Import from a local volume

The glance-direct method creates an image record, which generates an image ID. After the image is uploaded to the service from a local volume, it is stored in a staging area and is made active after it passes any configured checks. The glance-direct method requires a shared staging area when used in a highly available (HA) configuration.

Note

Image uploads that use the glance-direct method fail in an HA environment if a common staging area is not present. In an HA active-active environment, API calls are distributed to the Image service controllers. The download API call can be sent to a different controller than the API call to upload the image. For more information about configuring the staging area, see Storage Configuration section in the Advanced Overcloud Customization Guide.

The glance-direct method uses three different calls to import an image:

  • glance image-create
  • glance image-stage
  • glance image-import

You can use the glance image-create-via-import command to perform all three of these calls in one command. In the example below, replace uppercase words with the appropriate options.

glance image-create-via-import --container-format FORMAT --disk-format DISKFORMAT --name NAME --file /PATH/TO/IMAGE

After the image moves from the staging area to the back end location, the image is listed. However, it might take some time for the image to become active.

You can monitor the image availability by using the glance image-show <image_id> command. Replace <image_id with the ID you provided during image creation.

1.2.5. Delete an image

  1. In the dashboard, select Project > Compute > Images.
  2. Select the image you want to delete and click Delete Images.

1.2.6. Hide or unhide an image

You can hide public images from normal listings presented to users. For instance, you can hide obsolete CentOS 7 images and show only the latest version to simplify the user experience. Users can discover and use hidden images.

To hide an image:

glance image-update <image_id> --hidden 'true'

To create a hidden image, add the --hidden argument to the glance image-create command.

To unhide an image:

glance image-update <image_id> --hidden 'false'

1.2.7. Show hidden images

To list hidden images:

glance image-list --hidden 'true'

1.2.8. Enabling image conversion

With the GlanceImageImportPlugins parameter enabled, you can upload a QCOW2 image, and the Image service will convert it to RAW.

Note

Image conversion is automatically enabled when you use Red Hat Ceph Storage RBD to store images and boot Nova instances.

To enable image conversion, create an environment file that contains the following parameter value and include the new environment file with the -e option in the openstack overcloud deploy command:

parameter_defaults:
  GlanceImageImportPlugins:'image_conversion'

1.2.9. Converting an image to RAW format

Red Hat Ceph Storage can store, but does not support using, QCOW2 images to host virtual machine (VM) disks.

When you upload a QCOW2 image and create a VM from it, the compute node downloads the image, converts the image to RAW, and uploads it back into Ceph, which can then use it. This process affects the time it takes to create VMs, especially during parallel VM creation.

For example, when you create multiple VMs simultaneously, uploading the converted image to the Ceph cluster might impact already running workloads. The upload process can starve those workloads of IOPS and impede storage responsiveness.

To boot VMs in Ceph more efficiently (ephemeral back end or boot from volume), the glance image format must be RAW.

Procedure

  1. Converting an image to RAW might yield an image that is larger in size than the original QCOW2 image file. Run the following command before the conversion to determine the final RAW image size:

    qemu-img info <image>.qcow2
  2. Convert an image from QCOW2 to RAW format:

    qemu-img convert -p -f qcow2 -O raw <original qcow2 image>.qcow2 <new raw image>.raw

1.2.9.1. Configuring disk formats in the Image service (glance)

You can the configure the Image service (glance) to enable or reject disk formats by using the GlanceDiskFormats parameter.

Procedure

  1. Log in to the undercloud host as the stack user.
  2. Source the undercloud credentials file:

    $ source ~/stackrc
  3. Include the GlanceDiskFormats parameter in an environment file, for example, glance_disk_formats.yaml:

    parameter_defaults:
      GlanceDiskFormats:
        - <disk_format>
    • For example, use the following configuration to enable only RAW and ISO disk formats:

      parameter_defaults:
        GlanceDiskFormats:
        - raw
        - iso
    • Use the following example configuration to reject QCOW2 disk images:

      parameter_defaults:
        GlanceDiskFormats:
        - raw
        - iso
        - aki
        - ari
        - ami
  4. Include the environment file that contains your new configuration in the openstack overcloud deploy command with any other environment files that are relevant to your environment:

    $ openstack overcloud deploy --templates \
      -e <overcloud_environment_files> \
      -e <new_environment_file> \
      …
    • Replace <overcloud_environment_files> with the list of environment files that are part of your deployment.
    • Replace <new_environment_file> with the environment file that contains your new configuration.

For more information about the disk formats available in RHOSP, see Image service.

1.2.10. Storing an image in RAW format

With the GlanceImageImportPlugins parameter enabled, run the following command to store a previously created image in RAW format:

$ glance image-create-via-import \
    --disk-format qcow2 \
    --container-format bare \
    --name NAME \
    --visibility public \
    --import-method web-download \
    --uri http://server/image.qcow2
  • For --name, replace NAME with the name of the image; this is the name that will appear in glance image-list.
  • For --uri, replace http://server/image.qcow2 with the location and file name of the QCOW2 image.
Note

This command example creates the image record and imports it by using the web-download method. The glance-api downloads the image from the --uri location during the import process. If web-download is not available, glanceclient cannot automatically download the image data. Run the glance import-info command to list the available image import methods.