Chapter 2. Installing a bootc image and publishing to a registry

Procedure

1. Navigate to the Red Hat Ecosystem Catalog.
2. Search for the MicroShift container image by using the microshift-bootc keyword.
3. Open the container image page of the MicroShift container image.
4. Select the Get this image tab to view instructions for downloading the image.

5. Get access to the latest image on x86_64 and AArch64 platforms by logging into the registry using the following command:

   $ sudo podman login registry.redhat.io

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6. Download the bootc image by running the following command:

   $ podman pull registry.redhat.io/openshift4/microshift-bootc-rhel9:v4.18

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Procedure

1. Create a Containerfile that includes the following instructions:

   Example Containerfile for RHEL image mode

   FROM registry.redhat.io/rhel9/rhel-bootc:9.4
   
   ARG USHIFT_VER=4.18
   RUN dnf config-manager \
           --set-enabled rhocp-${USHIFT_VER}-for-9-$(uname -m)-rpms \
           --set-enabled fast-datapath-for-9-$(uname -m)-rpms
   RUN dnf install -y firewalld microshift && \
       systemctl enable microshift && \
       dnf clean all
   
   # Create a default 'redhat' user with the specified password.
   # Add it to the 'wheel' group to allow for running sudo commands.
   ARG USER_PASSWD
   RUN if [ -z "${USER_PASSWD}" ] ; then \
           echo USER_PASSWD is a mandatory build argument && exit 1 ; \
       fi
   RUN useradd -m -d /var/home/redhat -G wheel redhat && \
       echo "redhat:${USER_PASSWD}" | chpasswd
   
   # Mandatory firewall configuration
   RUN firewall-offline-cmd --zone=public --add-port=22/tcp && \
       firewall-offline-cmd --zone=trusted --add-source=10.42.0.0/16 && \
       firewall-offline-cmd --zone=trusted --add-source=169.254.169.1
   
   # Create a systemd unit to recursively make the root filesystem subtree
   # shared as required by OVN images
   RUN cat > /etc/systemd/system/microshift-make-rshared.service <<'EOF'
   [Unit]
   Description=Make root filesystem shared
   Before=microshift.service
   ConditionVirtualization=container
   [Service]
   Type=oneshot
   ExecStart=/usr/bin/mount --make-rshared /
   [Install]
   WantedBy=multi-user.target
   EOF
   RUN systemctl enable microshift-make-rshared.service

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   Important

   Podman uses the host subscription information and repositories inside the container when building the container image. If the rhocp and fast-datapath repositories are not available on the host, the build fails.

2. Set the PULL_SECRET environment variable:

   $ PULL_SECRET=~/.pull-secret.json

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3. Configure the USER_PASSWD environment variable:

   $ USER_PASSWD=<redhat_user_password> 

   1

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   1

   Replace <redhat_user_password> with your password.

4. Configure the IMAGE_NAME environment variable:

   $ IMAGE_NAME=microshift-4.18-bootc

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5. Create a local bootc image by running the following image build command:

   $ sudo podman build --authfile "${PULL_SECRET}" -t "${IMAGE_NAME}" \
       --build-arg USER_PASSWD="${USER_PASSWD}" \
       -f Containerfile

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   Important

   How secrets are used during the image build:

   • The podman --authfile argument is required to pull the base rhel-bootc:9.4 image from the registry.redhat.io registry.
   • The build USER_PASSWD argument is used to set a password for the redhat user.

Verification

1. Verify that the local MicroShift bootc image was created by running the following command:

   $ sudo podman images "${IMAGE_NAME}"

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   Example output

   REPOSITORY                       TAG         IMAGE ID      CREATED        SIZE
   localhost/microshift-4.18-bootc  latest      193425283c00  2 minutes ago  2.31 GB

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