feat: add pre-cache timer, force_pull, and Docker socket options to runner config

- Add force_pull: false (explicit default) to runner config template
- Add options field to mount host rootless Docker socket as /run/host-docker.sock
  so CI containers use the host daemon (full disk) instead of nested DinD
- Add valid_volumes list for the socket mount targets
- Add pre_cache.yml task with systemd timer that pre-pulls CI images every 6h
  to prevent thundering-herd registry timeouts when all runners start jobs
- Add docker-pull-images.service.j2 and docker-pull-images.timer.j2 templates
- Bump devx from v0.50.0 to v0.50.1 (includes start_docker.py host socket fix)

Closes GRM-162

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

ansible/roles/gitea_runner/defaults/main.yml

@@ -90,6 +90,22 @@ gitea_runner_remove_user: true
 gitea_runner_log_level: "info"
 gitea_runner_container_label: "gitea-runner=true"
 gitea_runner_file: ".runner"
+# force_pull: when false (default), the runner reuses locally cached images
+# instead of pulling on every job. Pre-cached images (via the pre-cache timer
+# or pre_pull_images task) eliminate registry thundering-herd when all runners
+# start jobs simultaneously.
+gitea_runner_force_pull: false
+# Container options passed to `docker run` for CI job containers.
+# Mounts the host rootless Docker socket as /run/host-docker.sock so
+# start_docker.py inside the container can detect and use the host daemon
+# (full disk, no nested DinD) instead of starting an inner dockerd.
+gitea_runner_container_options: "-v /run/user/{{ gitea_runner_uid }}/docker.sock:/run/host-docker.sock"
+# Volumes allowed in CI job containers (validated by the runner against
+# container.options and job-level volumes). Must include the host Docker
+# socket mount target.
+gitea_runner_valid_volumes:
+  - "/run/host-docker.sock"
+  - "/run/user/{{ gitea_runner_uid }}/docker.sock"
 
 # Containerd version pinning — Docker 28.x vendors containerd v2.1.x internally.
 # containerd.io >= 2.3 ships a shim that returns a protobuf BootstrapResult which
@@ -135,3 +151,11 @@ gitea_runner_docker_ipv6_cidr: "fd00:dead:beef::/48"
 # disk-space prune only removes dangling images, so pre-pulled tagged images persist.
 # Set to [] to skip pre-pulling. Images are pulled as the runner user via rootless Docker.
 gitea_runner_pre_pull_images: []
+
+# Pre-cache timer: periodically pulls the runner container image so it stays
+# fresh in the local Docker cache. This prevents thundering-herd registry
+# timeouts when all runners start CI jobs simultaneously with empty caches.
+# Runs every 6 hours (aligned with prune schedule). Set to empty string to
+# disable the timer.
+gitea_runner_pre_cache_schedule: "*-*-* 00/6:30:00"
+gitea_runner_pre_cache_images: "{{ gitea_runner_pre_pull_images }}"

ansible/roles/gitea_runner/tasks/main.yml

@@ -20,6 +20,9 @@
 - name: Include pre-pull images
   ansible.builtin.include_tasks: pre_pull_images.yml
 
+- name: Include pre-cache timer
+  ansible.builtin.include_tasks: pre_cache.yml
+
 - name: Include integration test
   ansible.builtin.include_tasks: integration_test.yml
   when: not gitea_runner_skip_registration

ansible/roles/gitea_runner/tasks/pre_cache.yml

@@ -0,0 +1,67 @@
+---
+# Periodic timer that pre-pulls CI runner images into the local Docker cache.
+# Prevents thundering-herd registry timeouts when all runners start jobs
+# simultaneously with empty/stale caches. Runs every 6 hours (configurable).
+# The prune timer removes dangling images but NOT tagged ones, so pre-pulled
+# images persist between runs.
+
+- name: Create docker-pull-images user service file
+  ansible.builtin.template:
+    src: docker-pull-images.service.j2
+    dest: "{{ gitea_runner_home }}/.config/systemd/user/docker-pull-images.service"
+    owner: "{{ gitea_runner_service_user }}"
+    group: "{{ gitea_runner_service_user }}"
+    mode: "0644"
+  register: gitea_runner_pre_cache_service
+
+- name: Create docker-pull-images user timer file
+  ansible.builtin.template:
+    src: docker-pull-images.timer.j2
+    dest: "{{ gitea_runner_home }}/.config/systemd/user/docker-pull-images.timer"
+    owner: "{{ gitea_runner_service_user }}"
+    group: "{{ gitea_runner_service_user }}"
+    mode: "0644"
+  register: gitea_runner_pre_cache_timer
+
+- name: Reload systemd user daemon for pre-cache timer
+  ansible.builtin.command: systemctl --user daemon-reload
+  become: true
+  become_user: "{{ gitea_runner_service_user }}"
+  environment:
+    XDG_RUNTIME_DIR: "/run/user/{{ gitea_runner_uid }}"
+    DBUS_SESSION_BUS_ADDRESS: "unix:path=/run/user/{{ gitea_runner_uid | default(0) }}/bus"
+  changed_when: true
+  when:
+    - gitea_runner_systemd_available.stat.exists
+    - gitea_runner_docker_rootless_setup
+    - gitea_runner_pre_cache_service is changed or gitea_runner_pre_cache_timer is changed
+    - gitea_runner_pre_cache_schedule | length > 0
+    - gitea_runner_pre_cache_images | length > 0
+
+- name: Enable and start docker-pull-images user timer
+  ansible.builtin.command: systemctl --user enable --now docker-pull-images.timer
+  become: true
+  become_user: "{{ gitea_runner_service_user }}"
+  environment:
+    XDG_RUNTIME_DIR: "/run/user/{{ gitea_runner_uid }}"
+    DBUS_SESSION_BUS_ADDRESS: "unix:path=/run/user/{{ gitea_runner_uid | default(0) }}/bus"
+  changed_when: true
+  when:
+    - gitea_runner_systemd_available.stat.exists
+    - gitea_runner_docker_rootless_setup
+    - gitea_runner_pre_cache_schedule | length > 0
+    - gitea_runner_pre_cache_images | length > 0
+
+- name: Disable and stop docker-pull-images timer (no images or schedule)
+  ansible.builtin.command: systemctl --user disable --now docker-pull-images.timer
+  become: true
+  become_user: "{{ gitea_runner_service_user }}"
+  environment:
+    XDG_RUNTIME_DIR: "/run/user/{{ gitea_runner_uid }}"
+    DBUS_SESSION_BUS_ADDRESS: "unix:path=/run/user/{{ gitea_runner_uid | default(0) }}/bus"
+  changed_when: true
+  failed_when: false
+  when:
+    - gitea_runner_systemd_available.stat.exists
+    - gitea_runner_docker_rootless_setup
+    - gitea_runner_pre_cache_schedule | length == 0 or gitea_runner_pre_cache_images | length == 0

ansible/roles/gitea_runner/templates/docker-pull-images.service.j2

@@ -0,0 +1,14 @@
+[Unit]
+Description=Pre-pull Docker images for CI runner cache
+After=docker.service
+Wants=docker.service
+
+[Service]
+Type=oneshot
+Environment=DOCKER_HOST=unix:///run/user/{{ gitea_runner_uid }}/docker.sock
+Environment=XDG_RUNTIME_DIR=/run/user/{{ gitea_runner_uid }}
+# Pull each image quietly. docker pull exits 0 if image is already up-to-date,
+# so this is idempotent. Errors are non-fatal (image may already be cached).
+{% for image in gitea_runner_pre_cache_images %}
+ExecStart=/usr/bin/docker pull -q {{ image }}
+{% endfor %}

ansible/roles/gitea_runner/templates/docker-pull-images.timer.j2

@@ -0,0 +1,10 @@
+[Unit]
+Description=Periodic Docker image pre-cache for CI runner
+
+[Timer]
+OnCalendar={{ gitea_runner_pre_cache_schedule }}
+Persistent=true
+RandomizedDelaySec=300
+
+[Install]
+WantedBy=timers.target

ansible/roles/gitea_runner/templates/gitea-runner-config.yaml.j2

@@ -9,3 +9,13 @@ runner:
 container:
   label: "{{ gitea_runner_container_label }}"
   docker_host: "unix:///run/user/{{ gitea_runner_uid }}/docker.sock"
+  force_pull: {{ gitea_runner_force_pull | lower }}
+{% if gitea_runner_container_options | length > 0 %}
+  options: "{{ gitea_runner_container_options }}"
+{% endif %}
+{% if gitea_runner_valid_volumes | length > 0 %}
+  valid_volumes:
+{% for volume in gitea_runner_valid_volumes %}
+    - "{{ volume }}"
+{% endfor %}
+{% endif %}

pyproject.toml

@@ -36,7 +36,7 @@ ci = [
     "build==1.5.1",
     "twine==6.2.0",
     # Reusable CI/CD and dev tools (auto-merge, pr-review, pre-push checks, etc.)
-    "devx @ git+https://git.oblachno.oblachno.fyi/oblachno-oss/devx.git@v0.50.0",
+    "devx @ git+https://git.oblachno.oblachno.fyi/oblachno-oss/devx.git@v0.50.1",
 ]
 # Lint and type-checking tools (validate job)
 lint = [
@@ -56,7 +56,7 @@ molecule = [
 dev = [
     "grm[ci,lint,molecule]",
     # Reusable CI/CD and dev tools (pre-push hooks, create-task, create-pr)
-    "devx @ git+https://git.oblachno.oblachno.fyi/oblachno-oss/devx.git@v0.50.0",
+    "devx @ git+https://git.oblachno.oblachno.fyi/oblachno-oss/devx.git@v0.50.1",
     # Non-Python dev dependency: checkmake (Makefile linter)
     # Install via: go install github.com/checkmake/checkmake/cmd/checkmake@latest
 ]