Add support for changing libvirt socket and pid path (#8)

Add support for changing libvirt socket and pid path

This allows you to use an uncontainerised libvirtd alongside
a containerised instance which has bind mounted /var/run/libvirt
into the container.

Author: jovial

README.md

@@ -37,11 +37,35 @@ default value is `true`.
 
 `libvirt_host_qemu_emulators`: List of architectures for which to install QEMU
 system emulators, e.g.  `x86`. The default value is `['x86']` if
+
 `libvirt_host_require_vt` is `false`, otherwise the default value is an empty
 list.
+
 `libvirt_host_enable_efi_support`: Whether to enable EFI support. This defaults 
 to false as extra packages need to be installed.
 
+`libvirt_host_var_prefix`: This determines The directory under /var/run that libvirt
+uses to store state, e.g unix domain sockets, as well as the default name of the 
+PID file. Override this if you have a conflict with the default socket e.g it 
+could be in use by the nova_libvirt container. Defaults to `""`.
+
+`libvirt_host_socket_dir`: Where the libvirtd socket is created. Defaults to
+`/var/run/{{ libvirt_host_var_prefix }}` if `libvirt_host_var_prefix` is set,
+otherwise `""`.
+
+`libvirt_host_pid_path`: Path to PID file which prevents multiple instances of
+the daemon from spawning. Defaults to `/var/run/{{ libvirt_host_var_prefix }}.pid` 
+if `libvirt_host_var_prefix` is set, otherwise `""`.
+
+`libvirt_host_libvirtd_args`: Command line arguments passed to libvirtd by the
+init system when libvirtd is started - quotes will be added
+
+`libvirt_host_uri`: The libvirt connnection URI. Defaults to 
+`qemu+unix:///system?socket={{ libvirt_host_socket_dir }}/libvirt-sock` if
+`libvirt_host_var_prefix` is set, otherwise `""`. If set to a falsey value,
+an explicit connection URI will not be set when calling virsh or any of
+the virt_ ansible modules.
+
 Dependencies
 ------------
 

defaults/main.yml

@@ -29,3 +29,35 @@ libvirt_host_qemu_emulators: "{{ [] if libvirt_host_require_vt | bool else ['x86
 # Whether or not to enable UEFI support. In some cases this requires installing
 # extra packages.
 libvirt_host_enable_efi_support: false
+
+# This determines The directory under /var/run that libvirt uses to store state,
+# e.g unix domain sockets, as well as the default name of the PID file. Override
+# this if you have a conflict with the default socket e.g it could be in use by the
+# nova_libvirt container
+libvirt_host_var_prefix: ""
+
+# Where the Unix Domain sockets are stored
+libvirt_host_socket_dir: >-
+  {%- if libvirt_host_var_prefix -%}
+  /var/run/{{ libvirt_host_var_prefix }}
+  {%- endif -%}
+
+# Path to PID file which prevents mulitple instances of the daemon from
+# spawning
+libvirt_host_pid_path: >-
+  {%- if libvirt_host_var_prefix -%}
+  /var/run/{{ libvirt_host_var_prefix }}.pid
+  {%- endif -%}
+
+# Command line arguments passed to libvirtd by the init system when
+# libvirtd is started - quotes will be added
+libvirt_host_libvirtd_args: >-
+  {%- if libvirt_host_pid_path -%}
+  -p {{ libvirt_host_pid_path }}
+  {%- endif %}
+
+# The libvirt connnection URI
+libvirt_host_uri: >-
+  {%- if libvirt_host_socket_dir -%}
+  qemu+unix:///system?socket={{ libvirt_host_socket_dir }}/libvirt-sock
+  {%- endif %}

handlers/main.yml

@@ -0,0 +1,7 @@
+---
+
+- name: restart libvirt
+  service:
+    name: libvirtd
+    state: restarted
+  become: true

tasks/config.yml

@@ -0,0 +1,42 @@
+---
+# Configure services - runs after the install stage
+
+- name: Set socket directory in libvirtd.conf
+  lineinfile:
+    path: /etc/libvirt/libvirtd.conf
+    insertafter: '^#unix_sock_dir ='
+    regexp: '^unix_sock_dir ='
+    line: unix_sock_dir = "{{ libvirt_host_socket_dir }}"
+  become: true
+  when: libvirt_host_socket_dir != ""
+  notify: restart libvirt
+
+- name: Create directory for libvirt socket
+  file:
+    state: directory
+    path: "{{ libvirt_host_socket_dir }}"
+    owner: root
+    group: root
+    mode: 0755
+  become: true
+  when: libvirt_host_socket_dir != ""
+
+- name: Process lineinfile rules
+  lineinfile: "{{ rule.args }}"
+  become: true
+  loop: "{{ libvirt_host_lineinfile_extra_rules | default([]) }}"
+  loop_control:
+    loop_var: rule
+  when: rule.condition
+  notify:
+    - restart libvirt
+
+- name: Flush handlers
+  meta: flush_handlers
+
+- name: Ensure the libvirt daemon is started and enabled
+  service:
+    name: libvirtd
+    state: started
+    enabled: yes
+  become: True

tasks/install.yml

@@ -1,13 +1,4 @@
 ---
-
-- name: gather os specific variables
-  include_vars: "{{ item }}"
-  with_first_found:
-    - "{{ ansible_distribution }}-{{ ansible_distribution_major_version}}.yml"
-    - "{{ ansible_distribution }}.yml"
-    - "{{ ansible_os_family }}.yml"
-  tags: vars
-
 - name: Install custom yum repositories
   # Although argument splatting is marked as deprecated:
   #
@@ -46,10 +37,3 @@
   become: True
   vars:
     package: "qemu-system-{{ item }}"
-
-- name: Ensure the libvirt daemon is started and enabled
-  service:
-    name: libvirtd
-    state: started
-    enabled: yes
-  become: True

tasks/main.yml

@@ -1,5 +1,16 @@
 ---
+- include: prelude.yml
 - include: validate.yml
 - include: install.yml
+- name: Run post-install stage
+  include: "{{ post_install_path }}"
+  with_first_found:
+    - files:
+        - post-install-{{ ansible_distribution }}.yml
+        - post-install-{{ ansible_os_family }}.yml
+      skip: true
+  loop_control:
+    loop_var: post_install_path
+- include: config.yml
 - include: pools.yml
 - include: networks.yml

tasks/networks.yml

@@ -4,19 +4,22 @@
     name: "{{ item.name }}"
     command: define
     xml: "{{ item.xml | default(lookup('template', 'network.xml.j2')) }}"
+    uri: "{{ libvirt_host_uri | default(omit, true) }}"
   with_items: "{{ libvirt_host_networks }}"
   become: True
 
 - name: Ensure libvirt networks are active
   virt_net:
     name: "{{ item.name }}"
     state: active
+    uri: "{{ libvirt_host_uri | default(omit, true) }}"
   with_items: "{{ libvirt_host_networks }}"
   become: True
 
 - name: Ensure libvirt networks are started on boot
   virt_net:
     name: "{{ item.name }}"
     autostart: yes
+    uri: "{{ libvirt_host_uri | default(omit, true) }}"
   with_items: "{{ libvirt_host_networks }}"
   become: True

tasks/pools.yml

@@ -15,19 +15,22 @@
     name: "{{ item.name }}"
     command: define
     xml: "{{ item.xml | default(lookup('template', 'pool.xml.j2')) }}"
+    uri: "{{ libvirt_host_uri | default(omit, true) }}"
   with_items: "{{ libvirt_host_pools }}"
   become: True
 
 - name: Ensure libvirt storage pools are active
   virt_pool:
     name: "{{ item.name }}"
     state: active
+    uri: "{{ libvirt_host_uri | default(omit, true) }}"
   with_items: "{{ libvirt_host_pools }}"
   become: True
 
 - name: Ensure libvirt storage pools are started on boot
   virt_pool:
     name: "{{ item.name }}"
     autostart: yes
+    uri: "{{ libvirt_host_uri | default(omit, true) }}"
   with_items: "{{ libvirt_host_pools }}"
   become: True

tasks/post-install-Debian.yml

@@ -0,0 +1,25 @@
+---
+
+- name: Determine path to libvirt environment file
+  # On Debian >= 8 and Ubuntu >= 16.04 the libvirt-bin package has been
+  # split into libvirt-daemon-system and libvirt-clients. They also seem
+  # to have changed to location to enviroment file. To prevent the need
+  # to hard code paths for every major version we determine these
+  # dynamically. This must be done after installing the package.
+  # You cannot guard the with_first_found with a condition without
+  # skip being set to true. This is undeseriable so we have to
+  # put it behind an include (a block doesn't work).
+  set_fact:
+    libvirt_host_lineinfile_extra_rules:
+      - args:
+          path: "{{ libvirt_env_path }}"
+          insertafter: '^#libvirtd_opts='
+          regexp: '^libvirtd_opts='
+          line: libvirtd_opts="{{ libvirt_host_libvirtd_args }}"
+        condition: "{{ libvirt_host_libvirtd_args != '' }}"
+  with_first_found:
+    - /etc/default/libvirt-bin
+    - /etc/default/libvirtd
+  loop_control:
+    loop_var: libvirt_env_path
+  tags: vars

tasks/prelude.yml

@@ -0,0 +1,10 @@
+---
+# This file is intended to be included at the beginning of a playbook.
+
+- name: gather os specific variables
+  include_vars: "{{ item }}"
+  with_first_found:
+    - "{{ ansible_distribution }}-{{ ansible_distribution_major_version}}.yml"
+    - "{{ ansible_distribution }}.yml"
+    - "{{ ansible_os_family }}.yml"
+  tags: vars