library/roles/ganglia: Mess with the kernel rmem values when a huge UDP buffer is needed.

library/roles/couchbase/tasks/ganglia-plugin.yml: Big UDP buffer to store the internal couchdb data.

couchbase/tasks/ganglia-plugin.yml

@@ -29,3 +29,4 @@
   when: not couchbase_ganglia_plugin_enabled
   notify: Restart ganglia monitor
   tags: [ 'ganglia', 'couchbase' ]
+

ganglia/defaults/main.yml

@@ -5,7 +5,10 @@
 #ganglia_gmond_cluster_port: 8649
 #ganglia_gmond_mcast_addr: 239.2.11.71
 #ganglia_gmetad_host: ganglia-gmetad
-ganglia_gmond_send_metadata_interval: 30
+ganglia_gmond_send_metadata_interval: 600
+# Set it to yes if you need a buffer bigger than the default
+ganglia_set_rmem: False
+ganglia_udp_recv_buffer: 131070
 # Needed to build the correct firewall rules when jmxtrans is in use
 ganglia_gmond_use_jmxtrans: False
 # Used by other roles to install specific ganglia iptables rules or some specific ganglia plugins. Or not.

ganglia/tasks/main.yml

@@ -79,3 +79,9 @@
   notify: Restart ganglia monitor
   when: is_precise
   tags: [ 'monitoring', 'ganglia' ]
+
+- name: Set the kernel UDP buffer limits (net.core.rmem_max) to a value that is double of the ganglia udp buffer
+  sysctl: name=net.core.rmem_max value={{ ganglia_udp_recv_buffer *2 }} reload=yes state=present
+  when: ganglia_set_rmem
+  tags: [ 'monitoring', 'ganglia' ]
+

ganglia/templates/gmond.j2

@@ -43,7 +43,8 @@ udp_send_channel {
 /* You can specify as many udp_recv_channels as you like as well. */ 
 udp_recv_channel { 
   mcast_join = {{ ganglia_gmond_mcast_addr }}
-  port = {{ ganglia_gmond_cluster_port }} 
+  port = {{ ganglia_gmond_cluster_port }}
+  buffer = {{ ganglia_udp_recv_buffer }}
 } 
 
 {% else %}
@@ -183,7 +184,7 @@ collection_group {
    set significantly higher to reduce unneccessary network chatter. */ 
 collection_group { 
   collect_every = 20 
-  time_threshold = 180
+  time_threshold = 360
   /* CPU status */ 
   metric { 
     name = "cpu_user"