diff --git a/.github/workflows/overcloud-host-image-build.yml b/.github/workflows/overcloud-host-image-build.yml
index 54777bd6cb..145cc3170f 100644
--- a/.github/workflows/overcloud-host-image-build.yml
+++ b/.github/workflows/overcloud-host-image-build.yml
@@ -212,7 +212,7 @@ jobs:
           source venvs/kayobe/bin/activate &&
           source src/kayobe-config/kayobe-env --environment ci-builder &&
           kayobe seed host command run \
-          --command "sudo apt update && sudo apt -y install gcc git libffi-dev python3-dev python-is-python3 python3-venv" --show-output
+          --command "sudo apt update && sudo apt -y install gcc git libffi-dev python3-dev python-is-python3 python3-venv containerd docker.io docker-buildx" --show-output
         env:
           KAYOBE_VAULT_PASSWORD: ${{ secrets.KAYOBE_VAULT_PASSWORD }}
 
diff --git a/.github/workflows/stackhpc-container-image-build.yml b/.github/workflows/stackhpc-container-image-build.yml
index 396fa40a59..657852dc80 100644
--- a/.github/workflows/stackhpc-container-image-build.yml
+++ b/.github/workflows/stackhpc-container-image-build.yml
@@ -190,17 +190,6 @@ jobs:
           localhost ansible_connection=local ansible_python_interpreter=/usr/bin/python3
           EOF
 
-      # See etc/kayobe/ansible/roles/pulp_auth_proxy/README.md for details.
-      # NOTE: We override pulp_auth_proxy_conf_path to a path shared by the
-      # runner and dind containers.
-      - name: Deploy an authenticating package repository mirror proxy
-        run: |
-          source venvs/kayobe/bin/activate &&
-          source src/kayobe-config/kayobe-env --environment ci-builder &&
-          kayobe playbook run $KAYOBE_CONFIG_PATH/ansible/pulp-auth-proxy.yml -e pulp_auth_proxy_conf_path=/home/runner/_work/pulp_proxy
-        env:
-          KAYOBE_VAULT_PASSWORD: ${{ secrets.KAYOBE_VAULT_PASSWORD }}
-
       - name: Create build logs output directory
         run: mkdir image-build-logs
 
@@ -222,6 +211,9 @@ jobs:
           args="$args -e stackhpc_repo_mirror_auth_proxy_enabled=true"
           args="$args -e kolla_build_log_path=$GITHUB_WORKSPACE/image-build-logs/kolla-build-overcloud.log"
           args="$args -e base_path=$GITHUB_WORKSPACE/opt/kayobe"
+          # NOTE: We override pulp_auth_proxy_conf_path to a path shared by the
+          # runner and dind containers.
+          args="$args -e pulp_auth_proxy_conf_path=/home/runner/_work/pulp_proxy"
           source venvs/kayobe/bin/activate &&
           source src/kayobe-config/kayobe-env --environment ci-builder &&
           kayobe overcloud container image build $args
diff --git a/etc/kayobe/environments/ci-builder/hooks/overcloud-container-image-build/pre.d/10-pulp-auth-proxy.yml b/etc/kayobe/environments/ci-builder/hooks/overcloud-container-image-build/pre.d/10-pulp-auth-proxy.yml
new file mode 120000
index 0000000000..6e84a71044
--- /dev/null
+++ b/etc/kayobe/environments/ci-builder/hooks/overcloud-container-image-build/pre.d/10-pulp-auth-proxy.yml
@@ -0,0 +1 @@
+../../../../../ansible/pulp-auth-proxy.yml
\ No newline at end of file
diff --git a/etc/kayobe/environments/ci-builder/hooks/overcloud-host-image-build/pre.d/10-pulp-auth-proxy.yml b/etc/kayobe/environments/ci-builder/hooks/overcloud-host-image-build/pre.d/10-pulp-auth-proxy.yml
new file mode 120000
index 0000000000..6e84a71044
--- /dev/null
+++ b/etc/kayobe/environments/ci-builder/hooks/overcloud-host-image-build/pre.d/10-pulp-auth-proxy.yml
@@ -0,0 +1 @@
+../../../../../ansible/pulp-auth-proxy.yml
\ No newline at end of file
diff --git a/etc/kayobe/environments/ci-builder/stackhpc-ci.yml b/etc/kayobe/environments/ci-builder/stackhpc-ci.yml
index 18a9958ab5..981c641dd5 100644
--- a/etc/kayobe/environments/ci-builder/stackhpc-ci.yml
+++ b/etc/kayobe/environments/ci-builder/stackhpc-ci.yml
@@ -36,6 +36,7 @@ kolla_build_neutron_ovs: true
 # Host and port of a package repository mirror.
 # Build against the development Pulp service repositories.
 # Use Ark's package repositories to install packages.
+stackhpc_repo_mirror_auth_proxy_enabled: true
 stackhpc_repo_mirror_url: "{{ stackhpc_repo_mirror_auth_proxy_url if stackhpc_repo_mirror_auth_proxy_enabled | bool else stackhpc_release_pulp_url }}"
 stackhpc_repo_mirror_username: "skc-ci-aio"
 stackhpc_repo_mirror_password: !vault |
diff --git a/etc/kayobe/environments/ci-builder/stackhpc-overcloud-host-images.yml b/etc/kayobe/environments/ci-builder/stackhpc-overcloud-host-images.yml
new file mode 100644
index 0000000000..886b1773a7
--- /dev/null
+++ b/etc/kayobe/environments/ci-builder/stackhpc-overcloud-host-images.yml
@@ -0,0 +1,3 @@
+---
+# Whether or not to build overcloud host images from Ark
+stackhpc_build_overcloud_image_from_pulp_package_mirrors: true
diff --git a/etc/kayobe/overcloud-dib.yml b/etc/kayobe/overcloud-dib.yml
index e824bdf5a0..625e86fa18 100644
--- a/etc/kayobe/overcloud-dib.yml
+++ b/etc/kayobe/overcloud-dib.yml
@@ -64,11 +64,7 @@ overcloud_dib_host_packages_extra:
 
 # List of additional git repositories containing Diskimage Builder (DIB)
 # elements. See stackhpc.openstack.os_images role for usage. Default is empty.
-overcloud_dib_git_elements_extra:
-  - repo: "https://github.com/stackhpc/stackhpc-image-elements"
-    local: "{{ source_checkout_path }}/stackhpc-image-elements"
-    version: "v1.6.3"
-    elements_path: "elements"
+overcloud_dib_git_elements_extra: "{{ stackhpc_dib_image_elements_repos }}"
 
 # List of git repositories containing Diskimage Builder (DIB) elements. See
 # stackhpc.openstack.os_images role for usage. Default is a combination of
diff --git a/etc/kayobe/pulp-host-image-versions.yml b/etc/kayobe/pulp-host-image-versions.yml
index 4a189c65b2..b118afb5b8 100644
--- a/etc/kayobe/pulp-host-image-versions.yml
+++ b/etc/kayobe/pulp-host-image-versions.yml
@@ -1,5 +1,5 @@
 ---
 # Overcloud host image versioning tags
 # These images must be in SMS, since they are used by our AIO CI runners
-stackhpc_rocky_9_overcloud_host_image_version: "2025.1-20250620T125648"
-stackhpc_ubuntu_noble_overcloud_host_image_version: "2025.1-20250620T125648"
+stackhpc_rocky_9_overcloud_host_image_version: "2025.1-20250916T145046"
+stackhpc_ubuntu_noble_overcloud_host_image_version: "2025.1-20250916T145046"
diff --git a/etc/kayobe/stackhpc-overcloud-dib.yml b/etc/kayobe/stackhpc-overcloud-dib.yml
index 99f5ae8362..89d6ac5984 100644
--- a/etc/kayobe/stackhpc-overcloud-dib.yml
+++ b/etc/kayobe/stackhpc-overcloud-dib.yml
@@ -22,6 +22,7 @@ stackhpc_overcloud_dib_name: "deployment_image"
 # StackHPC overcloud DIB image elements.
 stackhpc_overcloud_dib_elements:
   - "{{ os_distribution }}-{% if os_distribution == 'rocky' %}container-stackhpc{% else %}minimal{% endif %}"
+  - "{% if os_distribution == 'ubuntu' and stackhpc_repo_mirror_auth_proxy_enabled %}apt-no-verify-peer{% endif %}"
   - "cloud-init-datasources"
   - "{% if os_distribution == 'rocky' %}selinux-permissive{% endif %}"
   - "enable-serial-console"
@@ -34,7 +35,9 @@ stackhpc_overcloud_dib_elements:
   - "{% if os_distribution == 'ubuntu' %}sudoers{% endif %}"
 
 # StackHPC overcloud DIB image environment variables.
-stackhpc_overcloud_dib_env_vars:
+stackhpc_overcloud_dib_env_vars: "{{ stackhpc_overcloud_dib_env_vars_default | combine(stackhpc_overcloud_dib_env_vars_ark if stackhpc_build_overcloud_image_from_pulp_package_mirrors | bool else {}) }}"
+
+stackhpc_overcloud_dib_env_vars_default:
   DIB_BLOCK_DEVICE_CONFIG: "{{ stackhpc_overcloud_dib_block_device_config_uefi_lvm }}"
   DIB_BOOTLOADER_DEFAULT_CMDLINE: "nofb nomodeset gfxpayload=text net.ifnames=1 rd.auto"
   DIB_GRUB_TIMEOUT: "5"
@@ -43,22 +46,22 @@ stackhpc_overcloud_dib_env_vars:
   DIB_CONTAINERFILE_RUNTIME: "docker"
   DIB_CONTAINERFILE_NETWORK_DRIVER: "host"
   DIB_CONTAINERFILE_DOCKERFILE: "/opt/kayobe/src/stackhpc-image-elements/elements/rocky-container-stackhpc/containerfiles/9-stackhpc"
-  # NOTE: Not currently syncing Ubuntu packages, since the on_demand mirror in
-  # Ark does not work if the upstream mirror pulls packages (which it does
-  # sometimes).
-  # DIB_DISTRIBUTION_MIRROR: "{{ stackhpc_repo_ubuntu_focal_url if os_distribution == 'ubuntu' else '' }}"
   DIB_DRACUT_ENABLED_MODULES_DEFAULT_CONFIG: "{{ stackhpc_overcloud_dib_dracut_enabled_modules_default_config }}"
   DIB_RELEASE: "{{ overcloud_dib_os_release }}"
   DIB_SUDOERS_FILENAME: "no-fqdn"
   # Avoid DNS queries during sudo commands, since we might not always have working DNS.
   DIB_SUDOERS_CONFIG: |
     Defaults  !fqdn
-  # FIXME: Support templating repo files.
-  # DIB_YUM_MINIMAL_BOOTSTRAP_REPOS: /path/to/dir/containing/dib-mirror-*.repo
   YUM: dnf
   # Workaround for stack user home ownership bug
   DIB_IMAGE_CACHE: "/tmp/yum"
 
+stackhpc_overcloud_dib_env_vars_ark:
+  DIB_CONTAINERFILE_BUILDOPTS: >-
+    --build-arg=ROCKY_USE_MIRRORS=true
+    --build-arg=ROCKY_MIRROR_URLS={{ [stackhpc_repo_rocky_9_baseos_url, stackhpc_repo_rocky_9_appstream_url] | join(',') }}
+  DIB_DISTRIBUTION_MIRROR: "{{ stackhpc_repo_ubuntu_noble_url if os_distribution == 'ubuntu' else '' }}"
+
 # StackHPC overcloud DIB image packages.
 stackhpc_overcloud_dib_packages:
   - "ethtool"
diff --git a/etc/kayobe/stackhpc-overcloud-host-images.yml b/etc/kayobe/stackhpc-overcloud-host-images.yml
index c009f8e8fe..59c3626b8e 100644
--- a/etc/kayobe/stackhpc-overcloud-host-images.yml
+++ b/etc/kayobe/stackhpc-overcloud-host-images.yml
@@ -5,6 +5,9 @@
 # Whether or not to download overcloud host images from Ark
 stackhpc_download_overcloud_host_images: false
 
+# Whether or not to build overcloud host images from Ark
+stackhpc_build_overcloud_image_from_pulp_package_mirrors: false
+
 # The overcloud host image source, defined by os_distribution, os_release,
 # and the current stable version.
 stackhpc_overcloud_host_image_url: "{{ stackhpc_release_pulp_content_url_with_auth }}/kayobe-images/\
diff --git a/etc/kayobe/stackhpc.yml b/etc/kayobe/stackhpc.yml
index 4588d1e02f..46520315d9 100644
--- a/etc/kayobe/stackhpc.yml
+++ b/etc/kayobe/stackhpc.yml
@@ -201,3 +201,12 @@ stackhpc_amphora_image_version: "2025.1-20250619T113933"
 # Secret store to deploy as a Certificate Authority.
 # Valid options are "vault" and "openbao". Default is "openbao".
 stackhpc_ca_secret_store: openbao
+
+###############################################################################
+# diskimage-builder elements repos
+
+stackhpc_dib_image_elements_repos:
+  - repo: "https://github.com/stackhpc/stackhpc-image-elements"
+    local: "{{ source_checkout_path }}/stackhpc-image-elements"
+    version: "v1.6.4"
+    elements_path: "elements"
diff --git a/releasenotes/notes/build-images-from-ark-6eb0d5c8779bb970.yaml b/releasenotes/notes/build-images-from-ark-6eb0d5c8779bb970.yaml
new file mode 100644
index 0000000000..d1486252ee
--- /dev/null
+++ b/releasenotes/notes/build-images-from-ark-6eb0d5c8779bb970.yaml
@@ -0,0 +1,9 @@
+---
+features:
+  - |
+    Added support for building overcloud host images from Pulp package mirrors.
+    This feature can be toggled with the flag
+    ``stackhpc_build_overcloud_image_from_pulp_package_mirrors``. By default,
+    this feature is enabled in the ``ci-builder`` environment and disabled
+    otherwise. StackHPC overcloud host images will now be built with packages
+    from Ark.