Questions

To assess your understanding of the topics discussed in this chapter, please answer the following questions:

1. Explain to an interested layman in a few simple sentences what zero downtime deployment means.
2. How does SwarmKit achieve zero downtime deployments?
3. Contrary to traditional (non-containerized) systems, why does a rollback in Docker Swarm just work? Explain in a few short sentences.
4. Describe two to three characteristics of a Docker secret.
5. You need to roll out a new version of the inventory service. What does your command look like?  Here is some more information:
   1. The new image is called acme/inventory:2.1.
   2. We want to use a rolling update strategy with a batch size of two tasks.
   3. We want the system to wait for one minute after each batch.

6. You need to update an existing service named inventory with a new password that is provided through a Docker secret. The new secret is called MYSQL_PASSWORD_V2. The code in the service expects the secret to be called MYSQL_PASSWORD. What does the update command look like? (Note: we do not want the code of the service to be changed!)