Chapter 2. Obtaining and modifying container images
A containerized overcloud requires access to a registry with the required container images. This chapter provides information on how to prepare the registry and your overcloud configuration to use container images for Red Hat OpenStack Platform.
This guide provides several use cases to configure your overcloud to use a registry. Before attempting one of these use cases, it is recommended to familiarize yourself with how to use the image preparation command. See Section 2.2, “Container image preparation command usage” for more information.
2.1. Registry Methods
Red Hat OpenStack Platform supports the following registry types:
- Remote Registry
-
The overcloud pulls container images directly from
registry.access.redhat.com. This method is the easiest for generating the initial configuration. However, each overcloud node pulls each image directly from the Red Hat Container Catalog, which can cause network congestion and slower deployment. In addition, all overcloud nodes require internet access to the Red Hat Container Catalog. - Local Registry
-
The undercloud uses the
docker-distributionservice to act as a registry. This allows the director to synchronize the images fromregistry.access.redhat.comand push them to thedocker-distributionregistry. When creating the overcloud, the overcloud pulls the container images from the undercloud’sdocker-distributionregistry. This method allows you to store a registry internally, which can speed up the deployment and decrease network congestion. However, the undercloud only acts as a basic registry and provides limited life cycle management for container images.
The docker-distribution service acts separately from docker. docker is used to pull and push images to the docker-distribution registry and does not serve the images to the overcloud. The overcloud pulls the images from the docker-distribution registry.
- Satellite Server
- Manage the complete application life cycle of your container images and publish them through a Red Hat Satellite 6 server. The overcloud pulls the images from the Satellite server. This method provides an enterprise grade solution to store, manage, and deploy Red Hat OpenStack Platform containers.
Select a method from the list and continue configuring your registry details.
2.2. Container image preparation command usage
This section provides an overview on how to use the openstack overcloud container image prepare command, including conceptual information on the command’s various options.
Generating a Container Image Environment File for the Overcloud
One of the main uses of the openstack overcloud container image prepare command is to create an environment file that contains a list of images the overcloud uses. You include this file with your overcloud deployment commands, such as openstack overcloud deploy. The openstack overcloud container image prepare command uses the following options for this function:
--output-env-file- Defines the resulting environment file name.
The following snippet is an example of this file’s contents:
parameter_defaults: DockerAodhApiImage: registry.access.redhat.com/rhosp13/openstack-aodh-api:latest DockerAodhConfigImage: registry.access.redhat.com/rhosp13/openstack-aodh-api:latest ...
Generating a Container Image List for Import Methods
If you aim to import the OpenStack Platform container images to a different registry source, you can generate a list of images. The syntax of list is primarily used to import container images to the container registry on the undercloud, but you can modify the format of this list to suit other import methods, such as Red Hat Satellite 6.
The openstack overcloud container image prepare command uses the following options for this function:
--output-images-file- Defines the resulting file name for the import list.
The following is an example of this file’s contents:
container_images: - imagename: registry.access.redhat.com/rhosp13/openstack-aodh-api:latest - imagename: registry.access.redhat.com/rhosp13/openstack-aodh-evaluator:latest ...
Setting the Namespace for Container Images
Both the --output-env-file and --output-images-file options require a namespace to generate the resulting image locations. The openstack overcloud container image prepare command uses the following options to set the source location of the container images to pull:
--namespace- Defines the namespace for the container images. This is usually a hostname or IP address with a directory.
--prefix- Defines the prefix to add before the image names.
As a result, the director generates the image names using the following format:
-
[NAMESPACE]/[PREFIX][IMAGE NAME]
Setting Container Image Tags
The openstack overcloud container image prepare command uses the latest tag for each container image by default. However, you can select a specific tag for an image version using one of the following options:
--tag-from-label- Use the value of the specified container image labels to discover the versioned tag for every image.
--tag-
Sets the specific tag for all images. All OpenStack Platform container images use the same tag to provide version synchronicity. When using in combination with
--tag-from-label, the versioned tag is discovered starting from this tag.
2.3. Container images for additional services
The director only prepares container images for core OpenStack Platform Services. Some additional features use services that require additional container images. You enable these services with environment files. The openstack overcloud container image prepare command uses the following option to include environment files and their respective container images:
-e- Include environment files to enable additional container images.
The following table provides a sample list of additional services that use container images and their respective environment file locations within the /usr/share/openstack-tripleo-heat-templates directory.
| Service | Environment File |
|---|---|
| Ceph Storage |
|
| Collectd |
|
| Congress |
|
| Fluentd |
|
| OpenStack Bare Metal (ironic) |
|
| OpenStack Data Processing (sahara) |
|
| OpenStack EC2-API |
|
| OpenStack Key Manager (barbican) |
|
| OpenStack Load Balancing-as-a-Service (octavia) |
|
| OpenStack Shared File System Storage (manila) |
|
| Sensu |
|
The next few sections provide examples of including additional services.
Ceph Storage
If deploying a Red Hat Ceph Storage cluster with your overcloud, you need to include the /usr/share/openstack-tripleo-heat-templates/environments/ceph-ansible/ceph-ansible.yaml environment file. This file enables the composable containerized services in your overcloud and the director needs to know these services are enabled to prepare their images.
In addition to this environment file, you also need to define the Ceph Storage container location, which is different from the OpenStack Platform services. Use the --set option to set the following parameters specific to Ceph Storage:
--set ceph_namespace-
Defines the namespace for the Ceph Storage container image. This functions similar to the
--namespaceoption. --set ceph_image-
Defines the name of the Ceph Storage container image. Usually,this is
rhceph-3-rhel7. --set ceph_tag-
Defines the tag to use for the Ceph Storage container image. This functions similar to the
--tagoption. When--tag-from-labelis specified, the versioned tag is discovered starting from this tag.
The following snippet is an example that includes Ceph Storage in your container image files:
$ openstack overcloud container image prepare \
...
-e /usr/share/openstack-tripleo-heat-templates/environments/ceph-ansible/ceph-ansible.yaml \
--set ceph_namespace=registry.access.redhat.com/rhceph \
--set ceph_image=rhceph-3-rhel7 \
--tag-from-label {version}-{release} \
...OpenStack Bare Metal (ironic)
If deploying OpenStack Bare Metal (ironic) in your overcloud, you need to include the /usr/share/openstack-tripleo-heat-templates/environments/services-docker/ironic.yaml environment file so the director can prepare the images. The following snippet is an example on how to include this environment file:
$ openstack overcloud container image prepare \ ... -e /usr/share/openstack-tripleo-heat-templates/environments/services-docker/ironic.yaml \ ...
OpenStack Data Processing (sahara)
If deploying OpenStack Data Processing (sahara) in your overcloud, you need to include the /usr/share/openstack-tripleo-heat-templates/environments/services-docker/sahara.yaml environment file so the director can prepare the images. The following snippet is an example on how to include this environment file:
$ openstack overcloud container image prepare \ ... -e /usr/share/openstack-tripleo-heat-templates/environments/services-docker/sahara.yaml \ ...
2.4. Using the Red Hat registry as a remote registry source
Red Hat hosts the overcloud container images on registry.access.redhat.com. Pulling the images from a remote registry is the simplest method because the registry is already setup and all you require is the URL and namespace of the image you aim to pull. However, during overcloud creation, the overcloud nodes all pull images from the remote repository, which can congest your external connection. If that is a problem, you can either:
- Setup a local registry
- Host the images on Red Hat Satellite 6
Procedure
To pull the images directly from
registry.access.redhat.comin your overcloud deployment, an environment file is required to specify the image parameters. The following command automatically creates this environment file:(undercloud) $ openstack overcloud container image prepare \ --namespace=registry.access.redhat.com/rhosp13 \ --prefix=openstack- \ --tag-from-label {version}-{release} \ --output-env-file=/home/stack/templates/overcloud_images.yaml-
Use the
-eoption to include any environment files for optional services. -
If using Ceph Storage, include the additional parameters to define the Ceph Storage container image location:
--set ceph_namespace,--set ceph_image,--set ceph_tag.
-
Use the
-
This creates an
overcloud_images.yamlenvironment file, which contains image locations, on the undercloud. You include this file with your deployment.
2.5. Using the undercloud as a local registry
You can configure a local registry on the undercloud to store overcloud container images. This method involves the following:
-
The director pulls each image from the
registry.access.redhat.com. -
The director pushes each images to the
docker-distributionregistry running on the undercloud. - The director creates the overcloud.
-
During the overcloud creation, the nodes pull the relevant images from the undercloud’s
docker-distributionregistry.
This keeps network traffic for container images within your internal network, which does not congest your external network connection and can speed the deployment process.
Procedure
Find the address of the local undercloud registry. The address will use the following pattern:
<REGISTRY IP ADDRESS>:8787
Use the IP address of your undercloud, which you previously set with the
local_ipparameter in yourundercloud.conffile. For the commands below, the address is assumed to be192.168.24.1:8787.Create a template to upload the the images to the local registry, and the environment file to refer to those images:
(undercloud) $ openstack overcloud container image prepare \ --namespace=registry.access.redhat.com/rhosp13 \ --push-destination=192.168.24.1:8787 \ --prefix=openstack- \ --tag-from-label {version}-{release} \ --output-env-file=/home/stack/templates/overcloud_images.yaml \ --output-images-file /home/stack/local_registry_images.yaml-
Use the
-eoption to include any environment files for optional services. -
If using Ceph Storage, include the additional parameters to define the Ceph Storage container image location:
--set ceph_namespace,--set ceph_image,--set ceph_tag.
-
Use the
This creates two files:
-
local_registry_images.yaml, which contains container image information from the remote source. Use this file to pull the images from the Red Hat Container Registry (registry.access.redhat.com) to the undercloud. overcloud_images.yaml, which contains the eventual image locations on the undercloud. You include this file with your deployment.Check that both files exist.
-
Pull the container images from
registry.access.redhat.comto the undercloud.(undercloud) $ sudo openstack overcloud container image upload \ --config-file /home/stack/local_registry_images.yaml \ --verbose
Pulling the required images might take some time depending on the speed of your network and your undercloud disk.
NoteThe container images consume approximately 10 GB of disk space.
The images are now stored on the undercloud’s
docker-distributionregistry. To view the list of images on the undercloud’sdocker-distributionregistry using the following command:(undercloud) $ curl http://192.0.2.5:8787/v2/_catalog | jq .repositories[]
To view a list of tags for a specific image, use the
skopeocommand:(undercloud) $ skopeo inspect --tls-verify=false docker://192.0.2.5:8787/rhosp13/openstack-keystone | jq .RepoTags[]
To verify a tagged image, use the
skopeocommand:(undercloud) $ skopeo inspect --tls-verify=false docker://192.0.2.5:8787/rhosp13/openstack-keystone:13.0-44
The registry configuration is ready.
2.6. Using a Satellite server as a registry
Red Hat Satellite 6 offers registry synchronization capabilities. This provides a method to pull multiple images into a Satellite server and manage them as part of an application life cycle. The Satellite also acts as a registry for other container-enabled systems to use. For more details information on managing container images, see "Managing Container Images" in the Red Hat Satellite 6 Content Management Guide.
The examples in this procedure use the hammer command line tool for Red Hat Satellite 6 and an example organization called ACME. Substitute this organization for your own Satellite 6 organization.
Procedure
Create a template to pull images to the local registry:
$ source ~/stackrc (undercloud) $ openstack overcloud container image prepare \ --namespace=rhosp13 \ --prefix=openstack- \ --output-images-file /home/stack/satellite_images \
-
Use the
-eoption to include any environment files for optional services. -
If using Ceph Storage, include the additional parameters to define the Ceph Storage container image location:
--set ceph_namespace,--set ceph_image,--set ceph_tag.
NoteThis version of the
openstack overcloud container image preparecommand targets the registry on theregistry.access.redhat.comto generate an image list. It uses different values than theopenstack overcloud container image preparecommand used in a later step.-
Use the
-
This creates a file called
satellite_imageswith your container image information. You will use this file to synchronize container images to your Satellite 6 server. Remove the YAML-specific information from the
satellite_imagesfile and convert it into a flat file containing only the list of images. The followingsedcommands accomplish this:(undercloud) $ awk -F ':' '{if (NR!=1) {gsub("[[:space:]]", ""); print $2}}' ~/satellite_images > ~/satellite_images_namesThis provides a list of images that you pull into the Satellite server.
-
Copy the
satellite_images_namesfile to a system that contains the Satellite 6hammertool. Alternatively, use the instructions in the Hammer CLI Guide to install thehammertool to the undercloud. Run the following
hammercommand to create a new product (OSP13 Containers) to your Satellite organization:$ hammer product create \ --organization "ACME" \ --name "OSP13 Containers"
This custom product will contain our images.
Add the base container image to the product:
$ hammer repository create \ --organization "ACME" \ --product "OSP13 Containers" \ --content-type docker \ --url https://registry.access.redhat.com \ --docker-upstream-name rhosp13/openstack-base \ --name base
Add the overcloud container images from the
satellite_imagesfile.$ while read IMAGE; do \ IMAGENAME=$(echo $IMAGE | cut -d"/" -f2 | sed "s/openstack-//g" | sed "s/:.*//g") ; \ hammer repository create \ --organization "ACME" \ --product "OSP13 Containers" \ --content-type docker \ --url https://registry.access.redhat.com \ --docker-upstream-name $IMAGE \ --name $IMAGENAME ; done < satellite_images_names
Synchronize the container images:
$ hammer product synchronize \ --organization "ACME" \ --name "OSP13 Containers"
Wait for the Satellite server to complete synchronization.
NoteDepending on your configuration,
hammermight ask for your Satellite server username and password. You can configurehammerto automatically login using a configuration file. See the "Authentication" section in the Hammer CLI Guide.- If your Satellite 6 server uses content views, create a new content view version to incorporate the images.
Check the tags available for the
baseimage:$ hammer docker tag list --repository "base" \ --organization "ACME" \ --product "OSP13 Containers"
This displays tags for the OpenStack Platform container images.
Return to the undercloud and generate an environment file for the images on your Satellite server. The following is an example command for generating the environment file:
(undercloud) $ openstack overcloud container image prepare \ --namespace=satellite6.example.com:5000 \ --prefix=acme-osp13_containers- \ --tag-from-label {version}-{release} \ --output-env-file=/home/stack/templates/overcloud_images.yamlNoteThis version of the
openstack overcloud container image preparecommand targets the Satellite server. It uses different values than theopenstack overcloud container image preparecommand used in a previous step.When running this command, include the following data:
-
--namespace- The URL and port of the registry on the Satellite server. The default registry port on Red Hat Satellite is 5000. For example,--namespace=satellite6.example.com:5000. --prefix=- The prefix is based on a Satellite 6 convention. This differs depending on whether you use content views:-
If you use content views, the structure is
[org]-[environment]-[content view]-[product]-. For example:acme-production-myosp13-osp13_containers-. -
If you do not use content views, the structure is
[org]-[product]-. For example:acme-osp13_containers-.
-
If you use content views, the structure is
-
--tag-from-label {version}-{release}- Identifies the latest tag for each image. -
-e- Include any environment files for optional services. --set ceph_namespace,--set ceph_image,--set ceph_tag- If using Ceph Storage, include the additional parameters to define the Ceph Storage container image location. Note thatceph_imagenow includes a Satellite-specific prefix. This prefix is the same value as the--prefixoption. For example:--set ceph_image=acme-osp13_containers-rhceph-3-rhel7
This ensures the overcloud uses the Ceph container image using the Satellite naming convention.
-
-
This creates an
overcloud_images.yamlenvironment file, which contains the image locations on the Satellite server. You include this file with your deployment.
The registry configuration is ready.
2.7. Modifying containers images
Red Hat provides a set of pre-built container images through the Red Hat Container Catalog (registry.access.redhat.com). It is possible to modify these images and add additional layers to them. This is useful for adding RPMs for certified 3rd party drivers to the containers.
To ensure continued support for modified OpenStack Platform container images, ensure that the resulting images comply with the "Red Hat Container Support Policy".
This example shows how to customize the latest openstack-keystone image. However, these instructions can also apply to other images:
Procedure
Pull the image you aim to modify. For example, for the
openstack-keystoneimage:$ sudo docker pull registry.access.redhat.com/rhosp12/openstack-keystone:latest
Check the default user on the original image. For example, for the
openstack-keystoneimage:$ sudo docker run -it registry.access.redhat.com/rhosp12/openstack-keystone:latest whoami root
NoteThe
openstack-keystoneimage usesrootas the default user. Other images use specific users. For example,openstack-glance-apiusesglancefor the default user.Create a
Dockerfileto build an additional layer on an existing container image. The following is an example that pulls the latest OpenStack Identity (keystone) image from the Container Catalog and installs a custom RPM file to the image:FROM registry.access.redhat.com/rhosp12/openstack-keystone MAINTAINER Acme LABEL name="rhosp12/openstack-keystone-acme" vendor="Acme" version="2.1" release="1" # switch to root and install a custom RPM, etc. USER root COPY custom.rpm /tmp RUN rpm -ivh /tmp/custom.rpm # switch the container back to the default user USER root
Build and tag the new image. For example, to build with a local
Dockerfilestored in the/home/stack/keystonedirectory and tag it to your undercloud’s local registry:$ docker build /home/stack/keystone -t "192.168.24.1:8787/rhosp12/openstack-keystone-acme:rev1"
Push the resulting image to the undercloud’s local registry:
$ docker push 192.168.24.1:8787/rhosp12/openstack-keystone-acme:rev1
-
Edit your overcloud container images environment file (usually
overcloud_images.yaml) and change the appropriate parameter to use the custom container image.
The Container Catalog publishes container images with a complete software stack built into it. When the Container Catalog releases a container image with updates and security fixes, your existing custom container will not include these updates and will require rebuilding using the new image version from the Catalog.
