Which method most efficiently prevents the application from starting before the database?

A blueprint was developed for deploying a standard 3-tier hosting environment for a company’s applications. The blueprint includes a load balancer, multiple web servers, a database server, and a small test application.

During testing of the blueprint, the application fails to connect to the database. The cause is found to be the database software is still installing when the application starts.

Which method most efficiently prevents the application from starting before the database?
A . Use a local install instead of downloading
B . Create a loop to retry connection
C . Create a service dependency
D . Use a sleep statement in a start script

View Answer

Answer: C

Explanation:

A service dependency is a feature of Nutanix Calm that allows you to define the order of execution and the conditions for starting and stopping services in a blueprint. By creating a service dependency between the application and the database, you can ensure that the application will not start until the database is fully installed and ready. This avoids the need for manual intervention or inefficient workarounds like loops or sleep statements.

Reference: Nutanix Multicloud Automation Administration (NMCAA), page 41; Nutanix Certified Professional – Multicloud Automation (NCP-MCA), section 2.

Reference: https://portal.nutanix.com/page/documents/details?targetId=Nutanix-Calm-Admin-Operations-Guide-v3_2_7:Nutanix-Calm-Admin-Operations-Guide-v3_2_7