Describe the Tenets of the "12-Factor App" 350-901 Practice Questions (Page 6)

Questions 26–30

1. 26foundation · easy

   According to the 12-factor app methodology, how should administrative tasks (e.g., database migrations) be executed?

   • AAs separate scripts that are not part of the app's codebase.
   • BAs interactive commands executed on a developer's local machine.
   • CAs scheduled jobs that run automatically without manual intervention.
   • DAs one-off processes in the same environment as the app, using the same codebase and configuration.
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2. 27foundation · easy

   Why is it important to strictly separate the build, release, and run stages in a 12-factor app?

   • ATo allow each stage to be performed by a different team.
   • BTo reduce the number of servers needed.
   • CTo enable rollback to a previous release easily.
   • DTo make the build process faster.
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4. 28application · medium

   A company runs a web application that uses a PostgreSQL database and an SMTP service for email. They are migrating from a self-hosted PostgreSQL instance to a managed cloud database service. The application code currently has the database host, port, and credentials hardcoded in a configuration file. The team wants to make the swap without changing application code. What is the 12-factor compliant approach?

   • AStore the database URL and SMTP credentials in environment variables and update only the environment variables when switching providers.
   • BUpdate the configuration file with the new managed database credentials and redeploy the application.
   • CCreate a new deployment of the application with the managed database and keep the old deployment running until the migration is verified.
   • DRefactor the application to use a database abstraction layer so it can support both self-hosted and managed PostgreSQL.
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5. 29application · medium

   A company is designing a new microservice that handles user sessions. Currently, the service stores session data in memory on the application server. The team is planning to scale the service horizontally to handle increased load. What change is required to make the service 12-factor compliant?

   • ASerialize the session data to a file on the local disk of each server and read it back on request.
   • BUse sticky sessions on the load balancer so each user always hits the same server.
   • CMove session storage to a shared backing service like Redis or a database, and keep the application processes stateless.
   • DIncrease the memory of each server so all sessions can be held in memory even under peak load.
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6. 30application · medium

   A team is developing a Node.js application. A developer manually installed a package globally on their laptop using `npm install -g` and the application works locally. When the team deploys to a fresh CI/CD pipeline, the application fails because the global package is missing. The team wants to ensure the application builds and runs identically in all environments. What should the team do?

   • AUse a shell script that checks if the package is installed and installs it if missing, running it before the application starts.
   • BDocument the required global package in the README and ask each developer to install it manually before running the app.
   • CCopy the `node_modules` folder from the developer's laptop into the repository so the dependency is always available.
   • DAdd the package to the `dependencies` section of `package.json` and use a lockfile to pin the exact version, then run `npm ci` in the build stage.
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