Elastic Load Balancer u0026 Auto Scaling Essentials Quiz Quiz

Assess your understanding of Elastic Load Balancing and Auto Scaling principles, including traffic distribution, scalability, health checks, and high availability. This quiz covers key concepts and best practices for building robust, automatically scalable systems to handle variable workloads.

1. Basic Function of an Elastic Load Balancer

   Which primary function does an Elastic Load Balancer perform for web applications handling multiple user requests?

   1. Encrypts all application data at rest
   2. Analyzes user activity for security threats
   3. Distributes incoming network traffic across multiple servers
   4. Stores backup copies of user data

   Explanation: An Elastic Load Balancer's main job is to distribute incoming network traffic across several servers, ensuring no single server becomes overwhelmed. This helps improve application availability and reliability. Storing backups, encrypting at rest, and analyzing security threats are important tasks but are handled by different system components. Choosing the incorrect options would conflate traffic management with unrelated security or storage features.

2. Auto Scaling Group Purpose

   What is the main benefit of using an Auto Scaling Group when demand on your web service fluctuates unexpectedly?

   1. It permanently increases all server resources
   2. It automatically adjusts the number of running servers based on demand
   3. It schedules server reboots at a fixed interval
   4. It blocks all traffic during maintenance windows

   Explanation: Auto Scaling Groups help maintain performance and cost efficiency by increasing or decreasing the number of servers according to traffic. Permanently raising server resources would not optimize for cost during low demand. Blocking traffic and scheduling reboots are administrative tasks unrelated to dynamic scaling. The correct option describes the key advantage of auto scaling.

3. Health Checks in Load Balancing

   How does a load balancer handle a server that fails its health checks during operation?

   1. It stops sending new traffic to that server until it recovers
   2. It increases the health check frequency to overload detection
   3. It redirects all traffic only to the failed server
   4. It permanently shuts down the failed server

   Explanation: When a server fails health checks, the load balancer directs traffic away from that server until it passes the checks again. It does not shut down servers, as that could disrupt recovery; redirecting all traffic to a failed server would worsen outages. Increasing health check frequency may not help if the server is already unhealthy. The correct option supports reliability and uptime.

4. Sticky Sessions Concept

   Which feature allows a load balancer to consistently send a returning user's requests to the same server for session continuity?

   1. Round robin forwarding
   2. Network firewalls
   3. Distributed backups
   4. Sticky sessions (session affinity)

   Explanation: Sticky sessions, also called session affinity, ensure a user's requests are sent to the same server, which is helpful for applications that store session data locally. Distributed backups relate to data storage, not request routing. Network firewalls help with security, not session management. Round robin forwarding distributes requests evenly and does not guarantee user continuity.

5. Auto Scaling Policy Types

   Which type of policy can an Auto Scaling Group use to increase resources when average CPU usage passes a certain threshold?

   1. Data replication policy
   2. Fixed termination policy
   3. Target tracking policy
   4. Error forwarding policy

   Explanation: A target tracking policy adjusts the size of the group based on a defined metric, such as average CPU usage. Fixed termination policies are not used for scaling based on metrics. Data replication and error forwarding policies do not control the number of resources in use based on performance data. Only the correct option relates to automatic scaling by monitoring particular metrics.

6. Scaling in Multiple Availability Zones

   Why is it recommended to distribute your Auto Scaling group across multiple Availability Zones?

   1. To reduce the number of health checks required
   2. To disable internet access for certain servers
   3. To improve fault tolerance and minimize downtime in case of zone failure
   4. To guarantee faster local backup operations

   Explanation: Spreading resources across zones ensures continued service in the event one zone becomes unavailable, supporting high availability. Fast backups are unrelated to zone distribution. The number of health checks is not typically affected by multi-zone deployment. Disabling internet access is a security measure unconnected to the distribution of Auto Scaling groups.

7. Load Balancer Types

   Which load balancer type operates at the transport layer and is commonly used for routing TCP traffic?

   1. Network load balancer
   2. Application load balancer
   3. Object router balancer
   4. Packet session balancer

   Explanation: Network load balancers work at the transport layer (Layer 4) and are best suited for TCP traffic management. Application load balancers work at the application layer (Layer 7). The terms 'Object router balancer' and 'Packet session balancer' do not describe standard types of load balancers. The distinction is important for choosing the right load balancing method for different traffic types.

8. Scaling Down

   What happens to servers in an Auto Scaling Group when the group scales down due to reduced traffic?

   1. Database backups are triggered on all servers
   2. Unneeded servers are terminated to save resources
   3. Traffic is rerouted directly to users
   4. All servers are rebooted simultaneously

   Explanation: When scaling down, unnecessary servers are terminated, which reduces costs and resources. Backup operations and simultaneous reboots are not automatically initiated by scaling down. Rerouting traffic directly to users would bypass the infrastructure which is not secure or practical. The correct answer represents efficient resource management.

9. Benefits of Load Balancing

   Which advantage does load balancing provide for applications experiencing a sudden surge in user traffic?

   1. Generates daily access logs automatically
   2. Prevents server overload and improves application availability
   3. Compresses all user data transmitted to the servers
   4. Disables low-priority services

   Explanation: By spreading traffic among multiple servers, load balancing helps prevent any single server from being overwhelmed, maintaining application stability and availability. Compressing user data and generating logs are unrelated to traffic distribution. Disabling services is a resource-saving measure but not directly linked to the core benefit of load balancing.

10. Cooldown Period Purpose

    What is the primary purpose of the cooldown period in an Auto Scaling Group after a scaling activity occurs?

    1. To prevent multiple scaling actions from happening too quickly in succession
    2. To reset all user sessions
    3. To apply new firewall settings
    4. To encrypt the server disk automatically

    Explanation: A cooldown period delays further scaling activities, allowing the system to stabilize and metrics to update after a scaling action. Disk encryption, session resets, and firewall settings are unrelated to the timing of scaling events. This prevents inefficient or excessive scaling based on outdated information, which could lead to resource wastage or instability.