[cloud] Make ec2_vpc_route_table wait for the route to propagate (#35975)

* Stabilize ec2_vpc_route_table

Wait for route table to be present before attempting to use it

Sleep before getting the final state of the route table in case modifications are incomplete

* Conditionally wait if changes were made

* Simplify logic

lib/ansible/modules/cloud/amazon/ec2_vpc_route_table.py

@@ -224,6 +224,7 @@ route_table:
 '''
 
 import re
+from time import sleep
 from ansible.module_utils.aws.core import AnsibleAWSModule
 from ansible.module_utils.ec2 import ec2_argument_spec, boto3_conn, get_aws_connection_info
 from ansible.module_utils.ec2 import ansible_dict_to_boto3_filter_list
@@ -647,6 +648,12 @@ def ensure_route_table_present(connection, module):
         if not module.check_mode:
             try:
                 route_table = connection.create_route_table(VpcId=vpc_id)['RouteTable']
+                # try to wait for route table to be present before moving on
+                for attempt in range(5):
+                    if not get_route_table_by_id(connection, module, route_table['RouteTableId']):
+                        sleep(2)
+                    else:
+                        break
             except (botocore.exceptions.ClientError, botocore.exceptions.BotoCoreError) as e:
                 module.fail_json_aws(e, msg="Error creating route table")
         else:
@@ -678,6 +685,9 @@ def ensure_route_table_present(connection, module):
                                             purge_subnets=purge_subnets)
         changed = changed or result['changed']
 
+    if changed:
+        # pause to allow route table routes/subnets/associations to be updated before exiting with final state
+        sleep(5)
     module.exit_json(changed=changed, route_table=get_route_table_info(connection, module, route_table))