Merge pull request #21 from dinusha92/master

ECS cluster auto scaling down script

auto-scaling-ecs/scale_down_ecs.py

@@ -0,0 +1,83 @@
+'''
+/*
+ * Copyright (c) 2017, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
+ *
+ * WSO2 Inc. licenses this file to you under the Apache License,
+ * Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+'''
+
+
+#---------------Auto Scaling Down Instances When There Are No Running Containers---------------------
+import boto3
+import datetime 
+import math
+import time
+
+#Method to get the unix time
+def unix_time(time_stamp):
+    return time.mktime(time_stamp.timetuple())
+
+#Method to scale down the instances 
+def scale_down(containerInstance, container_instances_count):
+    print "\nContainer Instance ID: " + containerInstance['ec2InstanceId']
+    #Check if the instance state has running task or pending tasks and number of instances in the cluster is greater than 1
+    if (containerInstance['runningTasksCount'] == 0 and containerInstance['pendingTasksCount']== 0 and container_instances_count > 1):
+        #registration time of the container instance
+        time_reg = containerInstance['registeredAt']
+	#current time of the instance
+        current_time = datetime.datetime.now()
+        #next billing hour of the instance
+        hours_difference = (unix_time(current_time) - unix_time(time_reg))/(60*60)
+        next_billing_hour = time_reg + datetime.timedelta(hours=math.ceil(hours_difference))
+	print ("Next billing hour begins: %s" % next_billing_hour )
+        #check if the current time close to 45 minutes of the current billing hour
+        threshold_time = next_billing_hour - datetime.timedelta(minutes=15)
+        print ("Threshold time to kill: %s" % threshold_time )
+        print ("Current time: %s" % current_time )
+        if unix_time(threshold_time) < unix_time(current_time):
+            #Terminate the instance and number of available container instances would be decreased by 1
+            print "Terminating instance " + containerInstance['ec2InstanceId'] 
+            asgClient.terminate_instance_in_auto_scaling_group(InstanceId=containerInstance['ec2InstanceId'], ShouldDecrementDesiredCapacity=True)
+	    container_instances_count -= 1
+	    print ("Size of the cluster after termination %s\n" %container_instances_count)
+    #if there are running/pending containers inside the instances
+    else :
+        print ("Running Containers {} \nPending tasks {} \nCluster size {} \n ".format(containerInstance['runningTasksCount'],containerInstance['pendingTasksCount'],container_instances_count))
+
+
+#choose the aws user which to access the resources
+session = boto3.Session(profile_name='account2')
+
+#ecs client and auto scaling group resource generation
+ecsClient = session.client(service_name='ecs')
+asgClient = session.client(service_name='autoscaling')
+
+#list container instances of the cluster
+clusterListResp = ecsClient.list_container_instances(cluster='Jenkins-ECS')
+
+#details of each container
+containerDetails = ecsClient.describe_container_instances(cluster='Jenkins-ECS', containerInstances=clusterListResp['containerInstanceArns'])
+
+#Get the instances count in the cluster
+container_instances_count = len(containerDetails['containerInstances'])
+
+#loop through every instances to check if it should be terminated
+for containerInstance in containerDetails['containerInstances']:
+    scale_down(containerInstance, container_instances_count)
+
+
+
+
+