Allow setting the number of workers to be used.

Environments with large numbers of CPUs will create a large
number of workers which can have an unnecessarily large
impact on memory usage, particular where you know how many
workers are needed.

Change-Id: Ie4bb075310a61a0873c9e56e4974600dbb4794a1

lib/cinder

@@ -307,6 +307,9 @@ function configure_cinder {
     iniset $CINDER_CONF keystone_authtoken admin_tenant_name $SERVICE_TENANT_NAME
     iniset $CINDER_CONF keystone_authtoken admin_password $SERVICE_PASSWORD
 
+    if [ -n "$API_WORKERS" ]; then
+        iniset $CINDER_CONF DEFAULT osapi_volume_workers "$API_WORKERS"
+    fi
 }
 
 # create_cinder_accounts() - Set up common required cinder accounts

lib/glance

@@ -131,6 +131,10 @@ function configure_glance {
     # sections.
     iniset $GLANCE_API_CONF glance_store filesystem_store_datadir $GLANCE_IMAGE_DIR/
 
+    if [ -n "$API_WORKERS" ]; then
+        iniset $GLANCE_API_CONF DEFAULT workers "$API_WORKERS"
+    fi
+
     # Store the images in swift if enabled.
     if is_service_enabled s-proxy; then
         iniset $GLANCE_API_CONF DEFAULT default_store swift

lib/nova

@@ -516,6 +516,12 @@ function create_nova_conf {
     iniset $NOVA_CONF DEFAULT ec2_dmz_host "$EC2_DMZ_HOST"
     iniset_rpc_backend nova $NOVA_CONF DEFAULT
     iniset $NOVA_CONF glance api_servers "$GLANCE_HOSTPORT"
+
+    if [ -n "$API_WORKERS" ]; then
+        iniset $NOVA_CONF DEFAULT osci_compute_workers "$API_WORKERS"
+        iniset $NOVA_CONF DEFAULT ec2_workers "$API_WORKERS"
+        iniset $NOVA_CONF DEFAULT metadata_workers "$API_WORKERS"
+    fi
 }
 
 function init_nova_cells {

stackrc

@@ -505,6 +505,11 @@ UNDO_REQUIREMENTS=${UNDO_REQUIREMENTS:-True}
 # Allow the use of an alternate protocol (such as https) for service endpoints
 SERVICE_PROTOCOL=${SERVICE_PROTOCOL:-http}
 
+# Sets the maximum number of workers for various services and can restrict
+# the memory used where there are a large number of CPUs present
+# (the default number of workers for many services is the number of CPUs)
+# API_WORKERS=4
+
 # Local variables:
 # mode: shell-script
 # End: