Chapter 3. Composing a RHEL for Edge image using Image Builder in RHEL web console
Use Image Builder to create a custom RHEL for Edge image (OSTree commit).
To access Image Builder and to create your custom RHEL for Edge image, you can either use the RHEL web console interface or the command-line interface.
This section provides information about accessing Image Builder and creating RHEL for Edge images using the RHEL web console. To access Image Builder and to create RHEL for Edge images using CLI, see, Chapter 4, Composing a RHEL for Edge image using Image Builder command-line.
You can compose RHEL for Edge images using Image Builder in RHEL web console by performing the following high-level steps:
- Access Image Builder in RHEL web console
- Create a blueprint for RHEL for Edge image
- Create a user account for the RHEL for Edge image blueprint
- Create a RHEL for Edge image
- Download the RHEL for Edge image
3.1. Accessing Image Builder in the RHEL web console
To access Image Builder in RHEL web console, ensure that you have met the following prerequisites and then follow the procedure.
- You have installed a RHEL system.
- You have administrative rights on the system.
- You have subscribed the RHEL system to Redhat Subscription Manager (RHSM) or to Redhat Satellite server.
- The system is powered on and accessible over network.
- You have installed Image Builder on the system.
- On the RHEL system, access https://localhost:9090/ in a web browser.
- For more information about how to remotely access Image Builder, see Managing systems using the RHEL 8 web console document.
- Log in to the web console using an administrative user account.
- On the web console, in the left hand menu, click .
- Click .
- The Image Builder dashboard appears in the right pane.
- You can now proceed to create a blueprint for the RHEL for Edge images.
3.2. Creating a RHEL for Edge image blueprint using Image Builder in RHEL web console
To create a RHEL for Edge image blueprint using Image Builder in RHEL web console, ensure that you have met the following prerequisites and then follow the procedure.
- On a RHEL system, you have opened the Image Builder dashboard.
On the Image Builder dashboard, click.
A Create Blueprint dialogue box appears.
- Specify a name and description for the blueprint that you want to create.
The dashboard displays a list of available components.
From the Available Components, clickfor the component that you want to include in the blueprint.
To search for a specific component, enter the component name in the Filter By Name text box, and then press . The Component Details pane displays the component details and its dependent components. You can select the required version. The web console selects the latest version by default.
To remove a component from the blueprint, in the Available Components pane, click against the component name.Note
The blueprint to create a “RHEL for Edge Installer (.iso)” must be empty, that is, not customized with packages or user. You can provide a name and optionally, a description to the blueprint. The “RHEL for Edge Installer (.iso)” image type does not support blueprint customizations or package selection, so the build fails if any customization or packages are specified.
- In the Components Details pane, click .
Clickto save the blueprint.
A dialog box with the blueprint summary appears.
- Click .
From the Blueprints.breadcrumbs, click Back to
The Image Builder dashboard lists the blueprints that you created.
3.3. Adding a source to RHEL for Edge image blueprint
By default, the
yum official sources are available. You can use the sources defined in Image Builder,
metalink, to include the RPMs packages from custom third parties repositories and you can add them to blueprints. These sources are global and therefore available to all blueprints.
The System sources repositories are set up locally on your computer and cannot be disabled or removed from Image Builder. You can add additional custom sources and thus be able to access other contents than the System sources available on your system. Any RPM repository that is accessible from the host system is valid as a source. It is not possible to disable a System Source.
Perform the following steps to add a Source to your blueprints.
- You have opened the Image Builder interface of the RHEL 8 web console in a browser.
Click thebutton in the upper right corner.
A pop-up window appears with the available sources, their names and descriptions.
- On the right side of the pop-up window, click the button.
Add the desired Source name, the Source path, and the Source Type.
Optionally, check the boxes related to the
SSL Certificate- to verify a repository’s identity and enable an encrypted connection.
GPG Key- to validate signatures of RPM packages available in this repository.
Click. The screen shows the available sources window and lists the source you have added.Note
Adding repositories for different major versions of RHEL results in errors during the image build process. Building a version of RHEL that is different than the host system, is not supported in this version of Image Builder.
As a result, the new System source is available for use or any changes that you may want to make.
3.4. Creating an administrative user account for a RHEL for Edge image blueprint
The RHEL for Edge images you create using Image Builder have the root account locked and no other accounts included. Image Builder enables you to create a user account with password for a RHEL for Edge blueprint so that you can log in to the RHEL for Edge image created from the blueprint. For the administrative user account you can either have a password-based access or an SSH-key based access.
For Network-based installation that uses kickstart, you can also create a user account with Kickstart.
- You have created an SSH key that you can use for the user account to be created.
- You have accessed the Image Builder dashboard in the RHEL web console.
- You have created a blueprint for RHEL for Edge image.
On the Image Builder dashboard, find the blueprint for RHEL for Edge image.
To search a required blueprint, specify the blueprint name in the Filter by Name text box and then press.
Click the blueprint name.
Image Builder displays the blueprint details.
- On the Customizations tab, click .
On the Create User Account dialogue box, specify the required details and a password for the user account.
For password-based access, specify a password for the user account.
For SSH-based access, specify an SSH key for the user account.
Ensure that you select the Server administrator check box, if you want to provide administrators rights to the user account you are creating.
Image Builder creates a specified user account and displays the details.
You can create additional user accounts, if required.
3.5. Creating a RHEL for Edge image using Image Builder in RHEL web console
You can create RHEL for Edge images for network-based deployment by selecting “RHEL for Edge Commit (.tar)”.
- The “RHEL for Edge Commit (.tar)” commit image type is not directly bootable, even though it contains a full operating system. To boot commit image type, you must deploy it.
You can also create RHEL for Edge images for non-network-based deployment, by selecting “RHEL for Edge Container (.tar)” to serve a commit or “RHEL for Edge Installer (.iso)”. The non-network-based deployment builds a boot ISO image which installs an OSTree-based system using the "RHEL for Edge Container" in combination with the “RHEL for Edge Installer (.iso)” image type.
- The “RHEL for Edge Container (.tar)” image type creates an OSTree commit and embeds it into an OCI container with a web server. When the container is started, the web server serves the commit as an OSTree repository.
- The “RHEL for Edge Installer (.iso)” image type pulls the commit from the running container and creates an installable boot ISO with a kickstart file configured to use the embedded OSTree commit.
The following describes how to build a boot ISO which installs an OSTree-based system using the "RHEL for Edge Container" in combination with the "RHEL for Edge Installer" image types. The workflow has the same result as the Building OSTree Image guide with the new image types automating some of the steps.
Follow the steps in this procedure to create a RHEL for Edge image using Image Builder in RHEL web console.
- On a RHEL system, you have accessed the Image Builder dashboard.
- You have created a blueprint for RHEL for Edge image.
- On the Image Builder dashboard, for the blueprint that you have created for RHEL for Edge image, Create Image. To search for a specific blueprint, enter the blueprint name in the Filter By Name text box, and then press .
On the Create Image window, perform the following steps:
- From the Type dropdown list, select “RHEL for Edge Commit (.tar)” for network-based deployment. For non-network-based deployments, select “RHEL for Edge Container (.tar)” to serve a commit or “RHEL for Edge Installer (.iso)”, to consume the commit and deploy an OS with that commit.
- In the Repository URL textbox, specify the URL to the OSTree repository of the commit to embed in the image. For example, http://10.0.2.2:8080/repository/.
- In the Parent commit textbox, specify a previous commit, or leave it empty; if you do not have a commit at this time.
In the Ref textbox, specify a reference for where your commit is going to be created. By default, the web console specifies
The Parent commit argument can only be used for RHEL for Edge Commit (.tar) image type. Using the Repository URL and Parent commit arguments together results in errors.
Image Builder creates a RHEL for Edge image for the blueprint that you created.
To view the RHEL for Edge image creation progress, click thefrom the breadcrumbs, and then click the tab.Note
The image creation process takes a few minutes to complete. To abort the image creation process, click Stop from the More Options menu.
3.6. Downloading a RHEL for Edge image
After Image Builder successfully creates the RHEL for Edge image, download the image on the local host.
To download an image:
From the More Options menu, click .
The Image Builder downloads the file at your default download location.
The downloaded file consists of a
.tar file with an OSTree repository. This repository contains the commit and a
json file which contains information metadata about the repository content.