Azure Container Instances (ACI) for simple runs - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ service_behavior

intermediate

Understanding ACI container restart behavior

You deploy an Azure Container Instance (ACI) with a container that runs a script and then exits. What will happen to the container after the script finishes?

A The container will stop and remain in a stopped state.

B The container will pause and wait for manual restart.

C The container will be deleted automatically after the script finishes.

D The container will restart automatically and run the script again.

💡 Hint

Think about the default restart policy of ACI containers.

By default, ACI containers stop after the process inside finishes. They do not restart unless configured with a restart policy.

❓ Configuration

intermediate

Specifying CPU and memory for an ACI container

You want to deploy an Azure Container Instance with 2 CPUs and 3.5 GB of memory. Which of the following Azure CLI commands correctly specifies these resources?

A az container create --resource-group myGroup --name myContainer --image myImage --cpu 2 --memory 3.5GB

B az container create --resource-group myGroup --name myContainer --image myImage --cpu 2 --memory 3.5

C az container create --resource-group myGroup --name myContainer --image myImage --cpu-count 2 --memory 3.5

D az container create --resource-group myGroup --name myContainer --image myImage --cpu 2 --memory 3.5g

💡 Hint

Check the official Azure CLI parameter names for CPU and memory.

The correct parameters are --cpu for CPU cores and --memory for memory in GB without units.

❓ Architecture

advanced

Choosing ACI for batch job architecture

You need to run a batch job that processes files uploaded to Azure Blob Storage. The job runs for about 10 minutes per file and should scale automatically based on the number of files. Which architecture best uses Azure Container Instances?

A Use an Azure Function triggered by Blob Storage events to start a new ACI container for each file.

B Deploy a single ACI container that polls Blob Storage every minute and processes all files sequentially.

C Use Azure Logic Apps to run the batch job inside a single ACI container on a schedule.

D Deploy multiple ACI containers manually and assign files to each container by hand.

💡 Hint

Think about event-driven scaling and automation.

Using Azure Functions triggered by Blob Storage events to start ACI containers allows automatic scaling and parallel processing per file.

❓ security

advanced

Securing environment variables in ACI

You want to pass sensitive data like API keys to your Azure Container Instance securely. Which method is the best practice to provide these secrets to the container?

A Pass secrets as plain text environment variables in the container definition.

B Send secrets as command-line arguments when starting the container.

C Store secrets in Azure Key Vault and reference them in the container environment variables using managed identities.

D Hardcode secrets inside the container image before deployment.

💡 Hint

Consider secure secret storage and access methods in Azure.

Azure Key Vault with managed identities allows secure secret injection without exposing secrets in plain text.

✅ Best Practice

expert

Optimizing cost for short-lived ACI containers

You run many short-lived containers in Azure Container Instances that complete tasks in under 5 minutes. What is the best practice to minimize cost while ensuring fast startup?

A Use large CPU and memory sizes to reduce runtime, even if it increases per-second cost.

B Use Azure Container Apps instead of ACI for better cost optimization on short tasks.

C Use the smallest CPU and memory sizes possible to reduce per-second cost, accepting longer runtimes.

D Pre-warm containers by keeping them running idle to avoid startup delays.

💡 Hint

Think about balancing startup time and billing granularity.

Pre-warming containers avoids startup delays and can reduce total cost by minimizing idle billed time during startup.