Make prometheus the default devstack example

Change the devstack local.conf samples and devstack multinode
contributor doc to demonstrate deploying watcher with prometheus as
datasource instead of gnocchi. Keep the gnocchi as an alternative
deployment example.

Depends-On: https://review.opendev.org/c/openstack/watcher/+/946230
Depends-On: https://review.opendev.org/c/openstack/devstack-plugin-prometheus/+/946254

Change-Id: I721b550a03f9e5350a3f1ab10292faa1c50049a7

devstack/local.conf.controller

@@ -8,6 +8,11 @@ DATABASE_PASSWORD=stackdb
 RABBIT_PASSWORD=stackqueue
 SERVICE_PASSWORD=$ADMIN_PASSWORD
 SERVICE_TOKEN=azertytoken
+# Disable sg_core prometheus config copy
+PROMETHEUS_ENABLE=false
+# PROMETHEUS_CONFIG_FILE var conflicts with sg_core var
+# to avoid issue, set PROMETHEUS_CONF_DIR
+PROMETHEUS_CONF_DIR="${DEST}"
 
 HOST_IP=192.168.42.1 # Change this to your controller node IP address
 #HOST_IPV6=2001:db8::7
@@ -18,6 +23,10 @@ NETWORK_GATEWAY=10.254.1.1 # Change this for your network
 
 MULTI_HOST=1
 
+CEILOMETER_ALARM_THRESHOLD="6000000000"
+CEILOMETER_BACKENDS="sg-core"
+CEILOMETER_PIPELINE_INTERVAL="15"
+
 
 #Set this to FALSE if do not want to run watcher-api behind mod-wsgi
 #WATCHER_USE_MOD_WSGI=TRUE
@@ -40,8 +49,10 @@ disable_service ceilometer-acompute
 # Enable the ceilometer api explicitly(bug:1667678)
 enable_service ceilometer-api
 
-# Enable the Gnocchi plugin
-enable_plugin gnocchi https://github.com/gnocchixyz/gnocchi
+enable_service prometheus
+enable_plugin aodh https://opendev.org/openstack/aodh
+enable_plugin devstack-plugin-prometheus https://opendev.org/openstack/devstack-plugin-prometheus
+enable_plugin sg-core https://github.com/openstack-k8s-operators/sg-core main
 
 LOGFILE=$DEST/logs/stack.sh.log
 LOGDAYS=2
@@ -55,3 +66,42 @@ compute_monitors=cpu.virt_driver
 # can change this to just versioned when ceilometer handles versioned
 # notifications from nova: https://bugs.launchpad.net/ceilometer/+bug/1665449
 notification_format=both
+
+[[post-config|$WATCHER_CONF]]
+[prometheus_client]
+host = 127.0.0.1
+port = 9090
+
+[watcher_cluster_data_model_collectors.baremetal]
+period = 120
+
+[watcher_cluster_data_model_collectors.compute]
+period = 120
+
+[watcher_cluster_data_model_collectors.storage]
+period = 120
+
+[watcher_datasources]
+datasources = prometheus
+
+[[test-config|$TEMPEST_CONFIG]]
+[optimize]
+datasource = prometheus
+
+[service_available]
+sg_core = True
+
+[telemetry]
+ceilometer_polling_interval = 15
+disable_ssl_certificate_validation = True
+
+[telemetry_services]
+metric_backends = prometheus
+
+[compute]
+min_compute_nodes = 2
+min_microversion = 2.56
+
+[compute-feature-enabled]
+block_migration_for_live_migration = True
+live_migration = True