Setup rsync module per object server drive

This PR sets up rsync module per drive for swift object servers. This
improves resource distribution, and also allows us to utilise rsync
module changes to prevent disk writes to specific drives when they begin
filling up.

Enable this option by setting "swift_rsync_module_per_drive: True", this
will still default to False to match upstream defaults. Additionally the
rsync max connections has been increased to match upstream defaults.

Additionally we include rsync.d/*.conf files by default and set this
directory up, so that we can add individual configuration to disable
specific drives.

Change-Id: I2019cade5bf5f2878497d30ce738dff07786fa64

defaults/main.yml

@@ -217,11 +217,14 @@ swift: {}
 #         default: True
 
 # Set rsync max_connections vars
-swift_max_rsync_connections: 2
+swift_max_rsync_connections: 4
 swift_account_max_rsync_connections: "{{ swift_max_rsync_connections }}"
 swift_container_max_rsync_connections: "{{ swift_max_rsync_connections }}"
 swift_object_max_rsync_connections: "{{ swift_max_rsync_connections }}"
 
+# Set Swift to use rsync module per object server drive
+swift_rsync_module_per_drive: False
+
 # Set the managed regions as a list of swift regions to manage
 # Use for global clusters, default when not set is all regions.
 # swift_managed_regions:

releasenotes/notes/swift-rsync-module-per-drive-79b05af8276e7d6e.yaml

@@ -0,0 +1,12 @@
+---
+features:
+  - Enable rsync module per object server drive by setting
+    the ``swift_rsync_module_per_drive`` setting to ``True``.
+    Set this to configure rsync and swift to utilise individual
+    configuration per drive. This is required when disabling
+    rsyncs to individual disks. For example, in a disk full
+    scenario.
+upgrade:
+  - The ``swift_max_rsync_connections`` default value has
+    changed from 2 to 4 in order to match the OpenStack swift
+    documented value.

tasks/swift_pre_install.yml

@@ -69,6 +69,7 @@
     - { path: "/openstack/log/{{ inventory_hostname }}", owner: "{{ swift_syslog_user_name }}", group: "{{ swift_syslog_group_name }}" }
     - { path: "/var/cache/swift" }
     - { path: "{{ swift_system_home_folder }}" }
+    - { path: "/etc/rsync.d", owner: "root", group: "root" }
   tags:
     - swift-dirs
 

templates/object-server-replicator.conf.j2

@@ -23,3 +23,6 @@ replication_server = True
 log_facility = LOG_LOCAL4
 concurrency = 6
 reclaim_age = {{ reclaim_age | default(604800) }}
+{% if swift_rsync_module_per_drive %}
+rsync_module = {replication_ip}::object_{device}
+{% endif %}

templates/object-server.conf.j2

@@ -39,6 +39,9 @@ recon_lock_path = /var/lock
 log_facility = LOG_LOCAL4
 concurrency = 6
 reclaim_age = {{ reclaim_age | default(604800) }}
+{%   if swift_rsync_module_per_drive %}
+rsync_module = {replication_ip}::object_{device}
+{%   endif %}
 {% endif %}
 
 [object-updater]

templates/rsyncd.conf.j2

@@ -18,8 +18,46 @@ path = {{ swift_vars.mount_point | default(swift.mount_point) }}
 read only = false
 lock file = /var/lock/container.lock
 
+{% if swift_rsync_module_per_drive %}
+{### Set up per drive rsync modules #}
+{### Lets get the default groups for drives and find the default storage_policy #}
+{%   set def_groups = [ 'account', 'container' ] %}
+{%   for policy in swift.storage_policies %}
+{%     if policy.policy.default is defined and policy.policy.default == True %}
+{%       set _update = def_groups.append(policy.policy.name) %}
+{%     endif %}
+{%   endfor %}
+{### swift_vars needs to exist for swift_vars[setting] checks to work #}
+{%   if swift_vars is not defined %}
+{%     set swift_vars = {} %}
+{%   endif %}
+{%   set drives = swift_vars.drives | default(swift.drives | default([])) %}
+{### Loop through the drives to determine if they are in the object group #}
+{%   for drive in drives %}
+{%   set devAdded = False %}
+{### Check if groups is defined per host or drive #}
+{%     set groups = drives.groups | default(swift_vars.groups | default(swift.groups | default(def_groups))) %}
+{%     for group in groups %}
+{%       if group not in ['account', 'container'] %}
+{### We only want to add a device once so check if it was added already #}
+{%         if not devAdded | bool %}
+[object_{{ drive.name }}]
+max connections = {{ swift_object_max_rsync_connections }}
+path = {{ swift_vars.mount_point | default(swift.mount_point) }}
+read only = false
+lock file = /var/lock/object_{{ drive.name }}.lock
+
+{%         endif %}
+{%         set devAdded = True %}
+{%       endif %}
+{%     endfor %}
+{%   endfor %}
+{% else %}
 [object]
 max connections = {{ swift_object_max_rsync_connections }}
 path = {{ swift_vars.mount_point | default(swift.mount_point) }}
 read only = false
 lock file = /var/lock/object.lock
+
+{% endif %}
+&include /etc/rsync.d