Chapter 8. Deploying a RHEL for Edge image in a network-base environment

You can deploy a RHEL for Edge image using the RHEL installer graphical user interface or a Kickstart file. The overall process for deploying a RHEL for Edge image depends on whether your deployment environment is network-based or non-network-based.

Note

To deploy the images on bare metal, use a Kickstart file.

Network-based deployments

Deploying a RHEL for Edge image in a network-based environment involves the following high-level steps:

  1. Extract the image file contents.
  2. Set up a web server
  3. Install the image

8.1. Extracting RHEL for Edge image commit

After you download the commit, extract the .tar file and note the ref name and the commit ID.

The downloaded commit file consists of a .tar file with an OSTree repository. The OSTree repository has a commit and a compose.json file.

The compose.json file has information metadata about the commit with information such as the "Ref", the reference ID and the commit ID. The commit ID has the RPM packages.

To extract the package contents, perform the following the steps:

Prerequisites

  • Create a Kickstart file or use an existing one.

Procedure

  1. Extract the downloaded image .tar file:

    # tar xvf <UUID>-commit.tar
  2. Go to the directory where you have extracted the .tar file.

    It has a compose.json file and an OSTree directory. The compose.json file has the commit number and the OSTree directory has the RPM packages.

  3. Open the compose.json file and note the commit ID number. You need this number handy when you proceed to set up a web server.

    If you have the jq JSON processor installed, you can also retrieve the commit ID by using the jq tool:

    # jq '.["ostree-commit"]' < compose.json
  4. List the RPM packages in the commit.

    # rpm-ostree db list rhel/8/x86_64/edge --repo=repo
  5. Use a Kickstart file to run the RHEL installer. Optionally, you can use any existing file or can create one by using the Kickstart Generator tool.

    In the Kickstart file, ensure that you include the details about how to provision the file system, create a user, and how to fetch and deploy the RHEL for Edge image. The RHEL installer uses this information during the installation process.

    The following is a Kickstart file example:

    lang en_US.UTF-8
    keyboard us
    timezone Etc/UTC --isUtc
    text
    zerombr
    clearpart --all --initlabel
    autopart
    reboot
    user --name=core --group=wheel
    sshkey --username=core "ssh-rsa AAAA3Nza…​."
    rootpw --lock
    network --bootproto=dhcp
    
    ostreesetup --nogpg --osname=rhel --remote=edge --url=https://mirror.example.com/repo/ --ref=rhel/8/x86_64/edge

    The OStree-based installation uses the ostreesetup command to set up the configuration. It fetches the OSTree commit, by using the following flags:

    • --nogpg - Disable GNU Privacy Guard (GPG) key verification.
    • --osname - Management root for the operating system installation.
    • --remote - Management root for the operating system installation
    • --url - URL of the repository to install from.
    • --ref - Name of the branch from the repository that the installation uses.
    • --url=https://mirror.example.com/repo/ - is the address of the host system where you extracted the edge commit and served over nginx. You can use the address to reach the host system from the guest computer.

      For example, if you extract the commit image in the /var/www/html directory and serve the commit over nginx on a computer whose hostname is www.example.com, the value of the --url parameter is http://www.example.com/repo.

      Note

      Use the http protocol to start a service to serve the commit, because https is not enabled on the Apache HTTP Server.

8.2. Setting up a web server to install RHEL for Edge images

After you have extracted the RHEL for Edge image contents, set up a web server to provide the image commit details to the RHEL installer by using HTTP.

The following example provides the steps to set up a web server by using a container.

Prerequisites

Procedure

  1. Create the nginx configuration file with the following instructions:

    events {
    
    }
    
    http {
        server{
            listen 8080;
            root /usr/share/nginx/html;
                    }
             }
    
    pid /run/nginx.pid;
    daemon off;
  2. Create a Dockerfile with the following instructions:

    FROM registry.access.redhat.com/ubi8/ubi
    RUN yum -y install nginx && yum clean all
    COPY kickstart.ks /usr/share/nginx/html/
    COPY repo /usr/share/nginx/html/
    COPY nginx /etc/nginx.conf
    EXPOSE 8080
    CMD ["/usr/sbin/nginx", "-c", "/etc/nginx.conf"]
    ARG commit
    ADD ${commit} /usr/share/nginx/html/

    Where,

    • kickstart.ks is the name of the Kickstart file from the RHEL for Edge image. The Kickstart file includes directive information. To help you manage the images later, it is advisable to include the checks and settings for Greenboot checks. For that, you can update the Kickstart file to include the following settings:

      lang en_US.UTF-8
      keyboard us
      timezone Etc/UTC --isUtc
      text
      zerombr
      clearpart --all --initlabel
      autopart
      reboot
      user --name=core --group=wheel
      sshkey --username=core "ssh-rsa AAAA3Nza…​."
      
      ostreesetup --nogpg --osname=rhel --remote=edge
      --url=https://mirror.example.com/repo/
      --ref=rhel/8/x86_64/edge
      
      %post
      cat << EOF > /etc/greenboot/check/required.d/check-dns.sh
      #!/bin/bash
      
      DNS_SERVER=$(grep nameserver /etc/resolv.conf | cut -f2 -d" ")
      COUNT=0
      
      # check DNS server is available
      ping -c1 $DNS_SERVER
      while [ $? != '0' ] && [ $COUNT -lt 10 ]; do
      
      							
      							
      							
      							COUNT++
      echo "Checking for DNS: Attempt $COUNT ."
      sleep 10
      ping -c 1 $DNS_SERVER
      done
      EOF
      %end

      Any HTTP service can host the OSTree repository, and the example, which uses a container, is just an option for how to do this. The Dockerfile performs the following tasks:

      1. Uses the latest Universal Base Image (UBI)
      2. Installs the web server (nginx)
      3. Adds the Kickstart file to the server
      4. Adds the RHEL for Edge image commit to the server
  3. Build a Docker container

    # podman build -t name-of-container-image --build-arg commit=uuid-commit.tar .
  4. Run the container

    # podman run --rm -d -p port:8080 localhost/name-of-container-image

    As a result, the server is set up and ready to start the RHEL Installer by using the commit.tar repository and the Kickstart file.

8.3. Downloading RHEL Boot.iso image

You can download a Red Hat Boot ISO image from the Red Hat Customer Portal. The Red Hat Boot ISO image is used to launch the RHEL installer. The installer fetches the Kickstart file that you provide for installing RHEL for Edge images.

Prerequisites

Procedure

  1. Open a browser and access https://access.redhat.com/downloads.
  2. Under Infrastructure Management, click the ` Red Hat Enterprise Linux 8` Product.
  3. Click the Download Now button for the option " Red Hat Enterprise Linux 8 Boot ISO"

8.4. Installing the RHEL for Edge image using a Kickstart file

To install the RHEL for Edge image that uses a Kickstart file, use the web server. The web server uses the RHEL for Edge image commit.tar repository and the Kickstart file to start the RHEL Installer.

Prerequisites

Procedure

  1. Run the RHEL Anaconda Installer by using libvirt virt-install:

    virt-install \
    --name rhel-edge-test-1 \
    --memory 2048 \
    --vcpus 2 \
    --disk path=prepared_disk_image.qcow2,format=qcow2,size=8 \
    --os-variant rhel8 \
    --cdrom /home/username/Downloads/rhel-8-x86_64-boot.iso
  2. On the installation screen:

    Figure 8.1. Red Hat Enterprise Linux boot menu

    The Red Hat Enterprise Linux boot menu
    1. Press the e key to add an additional kernel parameter:

      inst.ks=http://edge_device_ip:port/kickstart.ks

      The kernel parameter specifies that you want to install RHEL by using the Kickstart file and not the RHEL image contained in the RHEL Installer.

    2. After adding the kernel parameters, press Ctrl+X to boot the RHEL installation by using the Kickstart file.

      The RHEL Installer starts, fetches the Kickstart file from the server (HTTP) endpoint and executes the commands, including the command to install the RHEL for Edge image commit from the HTTP endpoint. After the installation completes, the RHEL Installer prompts you for login details.

Verification

  1. On the Login screen, enter your user account credentials and click Enter.
  2. Verify whether the RHEL for Edge image is successfully installed.

    $ rpm-ostree status

    The command output provides the image commit ID and shows that the installation is successful.

    Following is a sample output:

    State: idle
    Deployments:
    * ostree://edge:rhel/8/x86_64/edge
    		  Timestamp: 2020-09-18T20:06:54Z
    			Commit: 836e637095554e0b634a0a48ea05c75280519dd6576a392635e6fa7d4d5e96