Add IPv6 check

src/playbooks/checks/check.yaml

@@ -0,0 +1,10 @@
+---
+- name: Run preflight checks
+  hosts: localhost
+  gather_facts: false
+  tasks:
+    - name: Run IPv6 check script
+      command: "{{ playbook_dir }}/../../roles/ipv6_check/files/foreman_ipv6_check"
+      register: ipv6_check
+      failed_when: ipv6_check.rc != 0
+

src/roles/ipv6_check/files/foreman_ipv6_check

@@ -0,0 +1,13 @@
+#!/bin/sh
+
+RED=$(tput setaf 1 2>/dev/null)
+RESET=$(tput sgr0 2>/dev/null)
+
+if grep -q "ipv6.disable=1" /proc/cmdline ; then
+  echo "${RED}FAIL${RESET}: The kernel contains ipv6.disable=1 which breaks installation and upgrade."
+  echo "Remove this boot parameter and reboot before continuing."
+  exit 2
+fi
+
+echo "IPv6 check: OK"
+exit 0

tests/unit/test_foreman_ipv6_check.py

@@ -0,0 +1,28 @@
+import subprocess
+import pytest
+import os
+
+TEST_DIR = os.path.dirname(os.path.abspath(__file__))
+SCRIPT_PATH = os.path.abspath(os.path.join(TEST_DIR, "..", "..", "src", "roles", "ipv6_check", "files", "foreman-ipv6-check"))
+
+if not os.path.exists(SCRIPT_PATH):
+    pytest.fail(f"Script not found at: {SCRIPT_PATH}")
+
+def run_script_with_mocked_cmdline(cmdline_content):
+    """Helper to mock /proc/cmdline using subprocess input."""
+    return subprocess.run(
+        ["bash", "-c", f'echo "{cmdline_content}" | {SCRIPT_PATH}'],
+        text=True,
+        capture_output=True,
+        shell=False,
+    )
+
+def test_ipv6_check_passes_on_valid_cmdline():
+    result = run_script_with_mocked_cmdline("quiet splash")
+    assert result.returncode == 0
+    assert "IPv6 check: OK" in result.stdout
+
+def test_ipv6_check_fails_on_disabled_ipv6():
+    result = run_script_with_mocked_cmdline("quiet splash ipv6.disable=1")
+    assert result.returncode == 2
+    assert "FAIL" in result.stdout or result.stderr