Fix linux_reboot: use /proc/1/environ container=lxc for reliable LXC detection across all distros

playbooks/linux_reboot.yml

@@ -12,18 +12,17 @@
       changed_when: false
 
     - name: Detect if running inside an LXC container
+      # Works on both Debian and Alpine — checks /proc/1/environ for container=lxc
+      # This is set by the Proxmox LXC runtime and is reliable across distros
       ansible.builtin.shell: |
-        grep -q 'lxc' /proc/1/environ 2>/dev/null \
-          || systemd-detect-virt --quiet --container 2>/dev/null \
-          || [ -f /run/.containerenv ] \
-          && echo "lxc" || echo "not-lxc"
+        cat /proc/1/environ | tr '\0' '\n' | grep -q '^container=lxc' && echo "lxc" || echo "none"
       register: virt_detect
       changed_when: false
       failed_when: false
 
     - name: Set is_lxc fact
       ansible.builtin.set_fact:
-        is_lxc: "{{ 'lxc' in virt_detect.stdout }}"
+        is_lxc: "{{ virt_detect.stdout | trim == 'lxc' }}"
 
     # ── Debian/Ubuntu ──────────────────────────────────────────────────────────
     - name: Get installed kernel version (Debian/Ubuntu)
@@ -36,8 +35,6 @@
       when: ansible_os_family == "Debian"
 
     - name: Normalize installed kernel version (Debian/Ubuntu)
-      # dpkg reports e.g. "6.12.74-2", uname -r reports "6.12.74+deb13+1-amd64"
-      # Extract just the base X.Y.Z for comparison
       ansible.builtin.set_fact:
         installed_kernel_version: "{{ installed_kernel_deb.stdout | trim }}"
         installed_kernel_base: "{{ installed_kernel_deb.stdout | trim | regex_replace('^(\\d+\\.\\d+\\.\\d+).*', '\\1') }}"
@@ -76,8 +73,8 @@
         running_kernel_base: "{{ running_kernel.stdout | trim | regex_replace('^(\\d+\\.\\d+\\.\\d+).*', '\\1') }}"
       when: ansible_os_family == "RedHat"
 
-    # ── Fallbacks ──────────────────────────────────────────────────────────────
-    - name: Set fallback for unknown/LXC hosts
+    # ── Fallback ───────────────────────────────────────────────────────────────
+    - name: Set fallback for unknown hosts
       ansible.builtin.set_fact:
         installed_kernel_version: "unknown"
         installed_kernel_base: "unknown"
@@ -101,6 +98,7 @@
           {{ inventory_hostname }}:
           running={{ running_kernel.stdout | trim }} (base={{ running_kernel_base }}),
           installed={{ installed_kernel_version }} (base={{ installed_kernel_base }}),
+          virt={{ virt_detect.stdout | trim }},
           is_lxc={{ is_lxc }},
           reboot_needed={{ reboot_needed }},
           force_reboot={{ force_reboot }}