AWS architect Interview Questions and Answers for 2025

EC2 stands for Elastic Cloud Compute. This technology is widely used to scale up computing capacities while eliminating the need for hardware architecture. The Amazon EC2 technology can launch multiple servers and manage security, networking, and storage all at once. Besides, while using EC2, the need for traffic forecast reduces as there are options to scale up and scale down as per the requirements.

Identity and Access Management (IAM) is a specialized web service dedicated to securing access to AWS resources. The IAM web service is vital to manage AWS users, access key credentials, and access permissions for AWS resources and applications.

A must-know for anyone heading into an AWS architect interview, this question is frequently asked in AWS architecture interview questions.  

The features of IAM are as follows: 

• Shared Access to our Account helps in sharing resources with the help of the shared access features. 
• Free of cost - AWS IAM is free to use, and also all the charges are added when we access other Amazon web services using IAM users. 
• Centralized control over your Aws account - Helps in the new creation of users and groups of any form of cancellation. 
• Grant permission to the user - It holds administrative rights, and the users can grant permission to access. 
• Multifactor Authentication - It adds layers of security implemented on our account by a third party. 

AWS policies are of two types:  

• Identity-based policies: This is the policy that binds with AWS identities, such as a user's, group or role. IAM policies are an example of that. These policies can be either Amazon Web Services managed or customer-managed.   
• Resource-based policies: AWS resource-based policies are the ones that can be tied directly to Amazon Resources, like a bucket policy (S3). Resource-based policies are only available for certain services.  

A common question in AWS solution architect interview questions for freshers, don't miss this one. 

• Do not use root accounts: Since root accounts have access to all the AWS resources and services, it is not a good idea to share or use them.  
• Use Groups: Create groups, grant access to them, and add users to them – so that all users within the group have the same access.  
• Enable Multi-factor Authentication (MFA): MFA should be enabled for privileged users such as admins. MFA adds an additional layer of security.  
• Grant least privileges: Only grant permissions that are necessary for the user or group.

Different types of load-balancers used in Amazon EC2 are: 

• Application Load Balancer: Used to make routing decisions at the application layer 
• Network Load Balancer: Used to make routing decisions at the transport layer 
• Classic Load Balancer: Used within the EC2-Classic network to balance load at varying EC2 instances.

A.9. AWS disaster recovery system enables businesses to quickly recover their critical IT systems without extra investment in a second infrastructure. The AWS cloud supports several disaster recovery architectures, including small customer workload data center failures to rapid failover at scale. Amazon has data centers worldwide, providing disaster recovery services to recover the business IT infrastructure quickly.

• Create a snapshot of the unencrypted root volume 
• Make a copy of the snapshot and select the encrypt option 
• Create an AMI from this encrypted snapshot 
• Now use this AMI to launch a new instance with encrypted volumes 

EC2 metadata is data about your EC2 instance. Let’s see an example to understand how we can use metadata in our cloud formation template script. 

View categories of instance metadata from within a running instance using the following IPv4 or IPv6 URIs. 

IPv4 

http://169.254.169.254/latest/meta-data/ 

IPv6 

http://[fd00:ec2::254]/latest/meta-data/ 
UserData: !Base64  
  'Fn::Sub': 
    - > 
      #!/bin/bash -x 
  
      # Installing packages and files using metadata 
  
      /opt/aws/bin/cfn-init -v --stack ${AWS::StackName} --resource TestInstance 
      --region ${AWS::Region} 
  
  
      # Send the status as signal from cfn-init 
  
      /opt/aws/bin/cfn-signal -e $? --stack ${AWS::StackName} --resource 
      TestInstance --region ${AWS::Region} 
    - {}

EC2 Userdata is a bootstrap script that gets executed once when the EC2 instance gets launched. Suppose we want to install an apache web server on our Linux instance; we can add the below script in our user data.

#! /bin/bash 
    sudo su 
    sudo yum update 
    sudo yum install -y httpd 
    sudo chkconfig httpd on 
    sudo service httpd start 
    echo "<h1>Deployed EC2 With Terraform</h1>" | sudo tee /var/www/html/index.html

Here is a list of default security features. 

• Security groups - This controls inbound and outgoing traffic at the instance level for EC2 instances, acting as a firewall. 
• Network access control lists – They serve as a subnet-level firewall, regulating inbound and outbound traffic.

VPC Flow Logs: The inbound and outbound traffic from the network interfaces in your VPC is recorded in flow logs.

• Authentication: It is how you sign into AWS using your credentials. As a principal, you must be authenticated (signed into AWS) using an entity (root user, IAM user, or IAM role) to send a request to AWS. An IAM user can have long-term credentials such as a username and password or a set of access keys. 
• Authorization: It is the security process that determines a user or service's level of access. In technology, we use authorization to give users or services permission to access some data or perform a particular action.

There are two models that you can use to run your containers: 

• Fargate launch type - This is a serverless pay-as-you-go option. You can run containers without needing to manage your Infrastructure. 
• EC2 launch type - Configure and deploy EC2 instances in your cluster to run your containers.

• S3 is object storage, and latency is higher than EBS and EFS; we can host/install OS or application on it 
• EBS is block storage, and it is the default storage with an Ec2 instance. We can attach 1 EBS with 1 instance.  
• EFS is Elastic File Storage. It is shared storage provided by AWS. We can attach 1 EFS with multiple Ec2 instances. 

Amazon is Amazon DAAS (Database as a Service) supports various databases like  

1. MSSql(Mysql Server) 
2. Oracle 
3. Postgres 
4. Aurora(serverless and provisioned) 
5. Maria DB 

It is similar to Aurora Database(MySQL and Postgres compatible). It's an on-demand database. In this database, we don’t have to manage/control database instances, and we need not pay the higher compute cost. It assigns compute power as required. In serverless compute capacity denote as ACU(Aurora Capacity unite) we can use mn 1 ACU(2BG RAM) to 256ACU(488GB RAM).

Internet gateways allow AWS resources/instances to connect to public internet on a public subnet, and it provides inbound and outbound traffic on AWS resources. Nat Gateway provides a connection under a private gateway; only inbound traffic is allowed on the NAT gateway.

• Network ACL: NACL stands for Network Access Control Lists. It is a security layer that works on VPC. It controls inbound and outbound internet on one or more subnets. 
• Security Group: It acts as a virtual firewall. It controls inbound and outbound traffic in instances 
• Difference: Network ACL works on the subnet level, and Security Group works on the Instance/machine level. 

In default monitoring, it monitors on a 5-minute span, and it’s free; when we enable detailed monitoring, it will start monitoring every 1-minute span. For detailed monitoring, we have to pay for this monitoring.

No, one subnet means the chunk of IP address, the pool of IP addresses that cannot expand across the availability zone. Multiple subnets can be in a single subnet. For example, there are two subnets, 10.0.1.0 and 10.0.2.0. So, these two subnets can be in EU West one B. But if there is a subnet which is 10.0.1.0, that cannot expand across a single availability zone. It means that it cannot be available within one within us East us West, one B and one A both. 

One of the most frequently posed solution architect AWS interview questions, be ready for it.  

AWS Route53 is a DNS service provided by AWS, it’s a highly scalable and highly available DNS management system, and it also provides a health-check web service. 

AWS route53 components are: 

1. DNS management 
2. Traffic management 
3. Availability monitoring 
4. Domain Registration

Route53 key features are: 

1. Resolver 
2. Traffic flow 
3. Latency-based routing 
4. Geo DNS 
5. Private DNS for Amazon VPC 
6. NS Failover 
7. Health Checks and Monitoring 
8. Domain Registration 
9. CloudFront Zone Apex Support 
10. S3 Zone Apex Support 
11. Amazon ELB Integration 
12. Management Console 
13. Weighted Round Robin 

No, both are different processes altogether. EC2 performs a regular shutdown when it is stopped. While it is in a stopped state, entire EBS volumes remain associated, so it is possible to start the instance anytime again when you want. When EC2 remains in the stopped state, users don’t need to pay for that particular time. Upon EC2 termination, the instance performs a regular shutdown and starts deleting EBS, which is associated with it. To save this kind of unwanted EBS loss, you can stop them from deleting simply by setting the “Delete on Termination” to false. Because the instance gets deleted, it is not possible to run it again in the future.

A staple in AWS SA interview questions, be prepared to answer this one.  

Migrating applications and data to the AWS cloud involve the following steps:   

• Planning Phase: Before starting the migration process, it is important to plan out the migration strategy. This includes identifying the applications and data that will be migrated, assessing their dependencies and requirements, and determining the target environment in AWS.   
• Pre-discovery and discovery phase: As part of this phase, the AWS migration specialist from AWS reviews the pre-confirmation application questionnaire as per the line of business. The AWS specialist also conducts interviews with application owners to validate the server inventory by going through a series of discovery-related questions to understand network and storage dependency requirements, high availability/disaster recovery (HA/DR) data points etc. 
• Migration path: There are several different approaches to migrating applications and data to AWS, depending on the specific needs and requirements of the applications and data. Some common approaches include  
  • Relocate: Containers/VMware Cloud on AWS 
  • Rehosting: Lift and shift 
  • Replatforming: Lift and reshape 
  • Repurchasing: Replace- drop and shop 
  • Refactoring: Rewriting or decoupling applications 
  • Retain/move 
  • Retire/decommission 
• Testing & Deployment: After the on-premises applications and data have been migrated, it is important to test them to ensure they function correctly in the AWS environment, which is taken care of by the application migration service, which is part of the AWS Migration hub.

Migrating applications and data to AWS involves careful planning, preparation, and testing to ensure a smooth and successful transition to the cloud.  

Different types of routing policies in Route53 are:  

• Simple Routing Policy: When there is only one resource performing the required function for the domain, a basic routing policy, which is a straightforward round-robin strategy, may be used. Based on the values in the resource record set, Route 53 answers DNS queries.  
• Weighted Routing Policy: Traffic is sent to separate resources according to predetermined weights, such as 75% to one server and 25% to the other, with the aid of a weighted routing policy.  
• Latency-based Routing Policy: To respond to a DNS query, a latency-based routing policy determines which data center provides us with the least amount of network latency.  
• Failover Routing Policy: In an active-passive failover arrangement, one resource (the primary) receives all traffic when it is functioning normally, and the other resource (the secondary) receives all traffic when the main is malfunctioning, which is permitted by failover routing rules.  
• Geolocation Routing Policy: To reply to DNS requests based on the users' geographic locations or the location from which the DNS requests originate, a geolocation routing policy is used.  
• Geoproximity Routing Policy: Based on the physical locations of the users and the resources, proximity routing assists in directing traffic to those locations.  
• Multivalue Routing Policy: Multiple values can be returned in answer to DNS requests thanks to multivalue routings, such as the IP addresses of the web servers. 

Create a service control policy in the root organizational unit to deny access to the services or actions. 

Service Control Policy concepts - 

• Service Control Policies offer centrally managed access controls for overall IAM entities in targeted accounts. You can use them to make sure to enforce the permissions you want everyone in your business to adhere to. Using Service Control Policies, you can give your proficient developers more freedom to manage their own permissions because you know they can now only operate within the boundaries you have defined for them. 
• You create and apply Service Control Policies through Amazon web services Organizations. When you create an organization, an AWS Organization automatically creates a root first, which forms the parent container for all the accounts in your organization. Inside the root account, you can group accounts in your organization into organizational units (OUs) to simplify the management of these targeted accounts. You can create multiple organizational units within a single organization, and you can create organizational units within other OUs to form a hierarchical structure. You can attach Service Control Policies to the organization's root, organizational units, and individual accounts. Service Control Policies attached to the root and OUs apply to all OUs and accounts inside of them. 
• SCPs use the AWS Identity and Access Management (IAM) policy language; however, they do not grant permissions. Service Control Policies enable you to set permission guardrails by defining the maximum available permissions for IAM entities in an account. If a Service Control Policies denies an action for an account, none of the entities in the account can take that action, even if their IAM permissions allow them to do so. The guardrails set in Service Control Policies apply to all 
• IAM entities in the account, which include all users, roles, and the account root user. 

Create a snapshot of the database. Copy it to an encrypted snapshot. Restore the database from the encrypted snapshot.

However, because you can encrypt a copy of an unencrypted DB snapshot, you can effectively add encryption to an unencrypted DB instance. That is, you can create a snapshot of your DB instance and then create an encrypted copy of that snapshot. You can then restore a DB instance from the encrypted snapshot, and thus you have an encrypted copy of your original DB instance.

• DB instances that are encrypted can't be modified to disable encryption.
• You can't have an encrypted read replica of an unencrypted DB instance or an unencrypted read replica of an encrypted DB instance.
• Encrypted read replicas must be encrypted with the same key as the source DB instance when both are in the same AWS Region.
• You can't restore an unencrypted backup or snapshot to an encrypted DB instance.
• To copy an encrypted snapshot from one AWS Region to another, you must specify the KMS key identifier of the destination AWS Region. This is because KMS encryption keys are specific to the AWS Region that they are created.

With target-tracking scaling policies, you select a scaling metric and set a target value. Amazon EC2 Autoscaling creates and manages the CloudWatch alarms that trigger the scaling policy and calculates the scaling adjustments based on the metric and the target value. The scaling policy adds or removes capacity as required to keep the metric at, or close to, the specified target value. In addition to keeping the metric close to the target value, a target tracking scaling policy also adjusts to changes in the metric due to a changing load pattern. For example, you can use target tracking scaling to Configure a target tracking scaling policy to keep the average aggregate CPU utilization of your Auto Scaling group at 40 percent. Configure a target tracking scaling policy to keep the request count per target of your Application Load Balancer target group at 1000 for your Autoscaling group.

With target-tracking scaling policies, you select a scaling metric and set a target value. Amazon EC2 Autoscaling creates and manages the CloudWatch alarms that trigger the scaling policy and calculates the scaling adjustments based on the metric and the target value. The scaling policy adds or removes capacity as required to keep the metric at, or close to, the specified target value. In addition to keeping the metric close to the target value, a target tracking scaling policy also adjusts to changes in the metric due to a changing load pattern. For example, you can use target tracking scaling to Configure a target tracking scaling policy to keep the average aggregate CPU utilization of your Auto Scaling group at 40 percent. Configure a target tracking scaling policy to keep the request count per target of your Application Load Balancer target group at 1000 for your Autoscaling group.

Use AWS Directory Service to create a managed Active Directory. Uninstall Active Directory on the current EC2 instance. 

Amazon Web Service Directory lets you run Microsoft Active Directory (AD) as a managed service. Amazon Web Service Directory for Microsoft Active Directory, also referred to as Amazon Web Service Managed Microsoft AD, is powered by Windows Server 2012 R2. When you target and launch this directory type, it creates a highly available pair of domain controllers connected to your AWS virtual private cloud (VPC). The domain controllers run in different AWS Availability Zones in an AWS region of your choice. Host monitoring and recovery, data replication, snapshots, and software updates are automatically configured and managed for you.

Install an Amazon web service Storage Gateway - file gateway hardware appliance on-premises to replicate the data to Amazon S3.

The perfect answer to this use case would be that we should opt for our very new Amazon FSx for Lustre. Amazon FSx for Lustre is a newly launched, fully managed service AWS based on the very well-known Lustre file system. 

This AWS Amazon FSx for Lustre provides you with a high-performance filesystem optimized for fast processing of your workloads, such as machine learning[ML], high-performance computing (HPC), video processing, financial modeling, and electronic design automation (EDA), which is very popular nowadays. 

AWS Amazon FSx for Lustre allows customers to create a Lustre filesystem on their demand and associate them to an Amazon S3(Simple Storage Service) bucket. As part of this filesystem creation, this Lustre reads the objects in the Amazon S3 buckets and adds that to the file system metadata. Any Lustre client in your AWS virtual private cloud is then able to access data, which gets cached on the high-speed Lustre filesystem. This is an ideal use case for HPC workloads because you can get the speed of an optimized and high-performant Lustre file system without having to manually manage the complexity of its deployments, optimization, and management of the Lustre cluster.

Amazon web services offer multiple options allowing you to choose based on your application or infrastructure needs.  

1. On-Demand EC2 Instances: Very popularly known as pay-as-you-go, it depends on the Amazon EC2 instance we select, there are no upfront costs, and we only pay for computing capacity per hour or per second. 
2. Spot EC2 Instances:  AWS Spot EC2 Instances can be purchased for up to 90% less than on-demand rates, and these are used to host workloads that are not business-critical. 
3. Reserved EC2 Instances: Here, we can reserve our instances based on our application or new application implementation roadmaps, where we can save up to 75% on AWS EC2 Reserved Instances when compared to the cost of On-Demand Instances.  
4. Dedicated Hosts:  With a dedicated host option, you purchase a whole physical host from AWS, and this host comes to you on an hourly basis billing manner similar to ec2 times are billed. 

Amazon S3 is one of the most popular and fully managed services by Amazon web service with below outstanding benefits it offers

• Simple data transfer 
• Scalability 
• Low cost 
• Flexibility 
• Security 
• Availability 
• Durability

To ensure data privacy and protection - 

• Use Encryption: Encrypt data at rest (e.g., S3, EBS) and in transit (e.g., TLS). 
• Implement IAM Policies: Apply the principle of least privilege. 
• Use VPC Security Features: Implement Security Groups and Network ACLs. 
• Enable Logging and Monitoring: Use AWS CloudTrail and CloudWatch to monitor and log activities. 
• Regularly Audit: Perform regular security assessments and audits using AWS Trusted Advisor and AWS Security Hub. 

AWS Lambda: Serverless compute service that runs code in response to events without provisioning or managing servers. It is ideal for short-duration tasks and supports automatic scaling. 

AWS Fargate: Serverless compute engine for containers that allows running Docker containers without managing servers. It is suitable for long-running applications and microservices architectures.