Handle reboot if kernel changed.

README.md

@@ -10,15 +10,14 @@ Requirements
 
 The role requires to be run as root on the target host.
 
-The system requires to be rebooted to apply the kernel change.
-
 The specified Kernel version must be supported by OS repositories (This include "Vault" repositories for Red hat based distributions).
 
 Role Variables
 --------------
 
 * **install_kernel_headers**: If True, also install matching kernel headers. Default to `true`.
 * **kernel_version**: Install the most recent kernel version available that start by this value. Default to `''`.
+* **reboot_on_kernel_update**: If True, reboot the system if the kernel was updated. Default to `true`.
 
 Example Playbook
 ----------------
@@ -30,16 +29,6 @@ Example Playbook
      - role: accelize.linux_kernel
   vars:
      kernel_version: 3.10.0-693
-
-  tasks:
-    # Reboot to apply the kernel change
-    - name: Ensure system is rebooted
-      reboot:
-    # If kernel version is required in a following step, update facts to get
-    # the new kernel version
-    - name: Ensure Ansible facts are up to date
-      setup:
-
 ```
 
 Dependencies

defaults/main.yml

@@ -4,3 +4,6 @@ install_kernel_headers: true
 
 # Kernel version to install (Default to latest available)
 kernel_version: ''
+
+# Reboot if kernel was updated
+reboot_on_kernel_update: true

filter_plugins/main.py

@@ -59,7 +59,7 @@ def rhel_repo(packages, kernel_version):
     return _rhel_kernel_info(packages, kernel_version)['repo']
 
 
-def _deb_kernel_info(packages, kernel_version):
+def deb_kernel(packages, kernel_version):
     """
     Return best matching kernel version.
 
@@ -133,7 +133,7 @@ def _deb_kernel_package(kernel, dist, arch, name):
     return '-'.join((name, kernel, suffix))
 
 
-def deb_kernel(packages, kernel_version, dist, arch, name):
+def deb_kernel_pkg(packages, kernel_version, dist, arch, name):
     """
     Return kernel package to install.
 
@@ -148,7 +148,7 @@ def deb_kernel(packages, kernel_version, dist, arch, name):
        str: kernel package to install.
     """
     return _deb_kernel_package(
-        _deb_kernel_info(packages, kernel_version), dist, arch, name)
+        deb_kernel(packages, kernel_version), dist, arch, name)
 
 
 def deb_installed_kernel(installed, packages, kernel_version):
@@ -164,7 +164,7 @@ def deb_installed_kernel(installed, packages, kernel_version):
        list of str: Kernel packages to remove.
     """
     # Filter installed package to keep
-    to_keep = _deb_kernel_info(packages, kernel_version)
+    to_keep = deb_kernel(packages, kernel_version)
 
     # Return installed package to remove
     to_remove = []
@@ -182,6 +182,20 @@ def deb_installed_kernel(installed, packages, kernel_version):
     return to_remove
 
 
+def kernel_match(kernel, kernel_spec):
+    """
+    Check if kernel version match.
+
+    Args:
+        kernel (str): Kernel
+        kernel_spec (str): Kernel to match.
+
+    Returns:
+        bool: True if Kernel match.
+    """
+    return kernel.startswith(kernel_spec)
+
+
 class FilterModule(object):
     """Return filter plugin"""
 
@@ -191,4 +205,6 @@ def filters():
         return {'rhel_kernel': rhel_kernel,
                 'rhel_repo': rhel_repo,
                 'deb_kernel': deb_kernel,
-                'deb_installed_kernel': deb_installed_kernel}
+                'deb_kernel_pkg': deb_kernel_pkg,
+                'deb_installed_kernel': deb_installed_kernel,
+                'kernel_match': kernel_match}

handlers/main.yml

@@ -0,0 +1,3 @@
+---
+- name: Update facts
+  setup:

molecule/default/playbook.yml

@@ -3,3 +3,5 @@
   hosts: all
   roles:
     - role: ansible-role-linux-kernel
+  vars:
+    reboot_on_kernel_update: false

tasks/main.yml

@@ -10,9 +10,13 @@
     - ansible_distribution_major_version == "7"
   register: yum_kernel_list
 
-- name: Install kernel with YUM
+- name: Set target YUM kernel version
+  set_fact: _kernel="{{ yum_kernel_list | rhel_kernel(kernel_version) }}"
+  when: yum_kernel_list is not skipped
+
+- name: Ensure kernel packages versions with YUM
   yum:
-    name: "{{ item.name }}-{{ yum_kernel_list | rhel_kernel(kernel_version) }}"
+    name: "{{ item.name }}-{{ _kernel }}"
     enablerepo: "{{ yum_kernel_list | rhel_repo(kernel_version) }}"
     allow_downgrade: true
   when:
@@ -37,9 +41,13 @@
     - ansible_distribution_major_version != "7"
   register: dnf_kernel_list
 
-- name: Install kernel with DNF
+- name: Set target DNF kernel version
+  set_fact: _kernel="{{ dnf_kernel_list | rhel_kernel(kernel_version) }}"
+  when: dnf_kernel_list is not skipped
+
+- name: Ensure kernel packages versions with DNF
   dnf:
-    name: "{{ item.name }}-{{ dnf_kernel_list | rhel_kernel(kernel_version) }}"
+    name: "{{ item.name }}-{{ _kernel }}"
     enablerepo: "{{ dnf_kernel_list | rhel_repo(kernel_version) }}"
     allow_downgrade: true
   when:
@@ -74,9 +82,13 @@
     - ansible_os_family == 'Debian'
   register: apt_packages_list
 
-- name: Install kernel with APT
+- name: Set target APT kernel version
+  set_fact: _kernel="{{ apt_kernel_list | deb_kernel(kernel_version) }}"
+  when: apt_kernel_list is not skipped
+
+- name: Ensure kernel packages versions with APT
   apt:
-    name: "{{ apt_kernel_list | deb_kernel(
+    name: "{{ apt_kernel_list | deb_kernel_pkg(
            kernel_version, ansible_distribution, ansible_architecture,
            item.name) }}"
   when:
@@ -88,10 +100,30 @@
     - name: linux-headers
       when: install_kernel_headers | bool
 
-- name: Remove previous kernels with APT
+- name: Ensure any other kernel packages are removed with APT
   apt:
     name: "{{ apt_packages_list | deb_installed_kernel(
            apt_kernel_list, kernel_version) }}"
     state: absent
     purge: true
   when: ansible_os_family == 'Debian'
+
+- name: Get /var/run/reboot-required stat
+  # Note: Should exist on Debian based OS if reboot is required
+  stat:
+    path: /var/run/reboot-required
+  register: reboot_flag
+
+- name: Notify about Kernel update and reboot requierement
+  debug:
+    msg: 'REBOOT REQUIRED, kernel version changed
+          from {{ ansible_kernel }} to {{ _kernel }}.'
+  when:
+    - (not (ansible_kernel | kernel_match(_kernel)) or reboot_flag.stat.exists)
+
+- name: Ensure the new kernel is enabled by rebooting
+  reboot:
+  when:
+    - reboot_on_kernel_update | bool
+    - (not (ansible_kernel | kernel_match(_kernel)) or reboot_flag.stat.exists)
+  notify: 'Update facts'