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

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=http://mirror.example.com/repo/ - is the address of the host system where you extracted the edge commit and served it 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.

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.

Procedure

1. Run the RHEL Anaconda Installer by using the libvirt virt-install utility to create a virtual machine (VM) with a RHEL operating system. Use the .qcow2 disk image as the target disk in the attended installation:

   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

   

   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

Procedure

1. Run a RHEL for Edge Container image to start a web server. The server fetches the commit in the RHEL for Edge Container image and becomes available and running.

2. Run the RHEL Anaconda Installer, passing the customized .qcow2 disk image, 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

3. On the installation screen:

   Figure 8.2. Red Hat Enterprise Linux boot menu

   

   1. Press the TAB key and add the Kickstart kernel argument:

      inst.ks=http://web-server_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.

   The following is a sample output:

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