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AWS Certified Solutions Architect Exam Guide – Chapter-10

April 29, 2021 comments off

Know how to use Amazon ElastiCache.
Improve the performance of your application by deploying Amazon ElastiCache cluster as part of your application and offloading read requests for frequently accessed data, Use the cache-aside pattern in your application first to check the cache for your query results before checking the database.

Understand when to use a specific cache engine.
Amazon ElastiCache gives you the Choice of cache engine to suit your requirements. Use Memcached when you need a simple, in-memory object store that can be easily partitioned and scaled horizontally. Use Redis when you need to back up and restore your data, need many clones or read replicas, or are looking for advanced functionality like sort and rank or leaderboards that Redis natively supports.

Understand how to scale a Redis cluster horizontally.
An Amazon ElastiCache cluster running Redis can be scaled horizontally first by creating a replication group, then by creating additional clusters and adding them to the replication group.

Understand how to scale a Memcached cluster horizontally.
An Amazon ElastiCache cluster running Memcached can be scaled horizontally by adding or removing additional cache nodes to the cluster. The Amazon ElastiCache client library supports Auto Discovery and can discover new nodes added or removed from the cluster without having to hardcode the list of nodes.

Know how to back up your Amazon ElastiCache cluster.
You can create a snapshot to back up your Amazon ElastiCache clusters running the Redis engine. Snapshots can be created automatically on a daily basis or manually on demand. Amazon ElastiCache clusters running Memcached do not support backup and restore natively.
 
Exercises
In this section, you will create a cache cluster using Amazon ElastiCache, expand the cluster with additional nodes, and finally create a replication group with an Amazon ElastiCache Radis cluster.

EXERCISE 10.1
Create an Amazon ElastiCache Cluster Running Memcached
In this exercise, you will create an Amazon ElastiCache cluster using the Memcached engine.

  1. While signed into the AWS Management Console, open the Amazon ElastiCache service dashboard.
  2. Begin the launch and configuration process to create a new Amazon ElastiCache cluster.
  3. Select the Memcached cache engine, and configure the cluster name, number of nodes, and node type.
  4. Optionally configure the security group and maintenance window as needed.
  5. Review the cluster configuration, and begin provisioning the cluster.
  6. Connect to the cluster with any Memcached client using the DNS name of the cluster.
    You have now created your first Amazon ElastiCache cluster.

EXERCISE 10.2
Expand the Size of a Memcached Cluster
In this exercise, you will expand the size of an existing Amazon ElastiCache Memcached cluster.

  1. Launch a Memcached cluster using the steps defined in Exercise 10.1.
  2. Go to the Amazon ElastiCache dashboard, and view the details of your existing cluster.
  3. View the list of nodes currently provisioned, and then add one additional node by increasing the number of nodes.
  4. Apply the configuration change, and wait for the new node to finish the provisioning process.
  5. Verify that the new node has been created, and connect to the node using a Memcached client.
    In this exercise, you have horizontally scaled an existing Amazon ElastiCache cluster by adding a cache node.

EXERCISE 10.3
Create an Amazon ElastiCache Cluster and Redis Replication Group
In this exercise, you will create an Amazon ElastiCache cluster using Redis nodes, create replication group, and set up a read replica.

  1. Sign in to the AWS Management Console, and navigate to the Amazon ElastiCache service dashboard.
  2. Begin the configuration and launch process for a new Amazon ElastiCache cluster.
  3. Select the Redis cache engine, and then configure a replication group and the node type.
  4. Configure a read replica by setting the number of read replicas to 1, and verify that Enable Replication and Multi-AZ are selected.
  5. Adjust the Availability Zones for the primary and read replica’ clusters, security groups, and maintenance window, as needed.
  6. Review the cluster configuration, and begin provisioning the cluster.
  7. Connect to the primary node and the read replica node with a Redis client library. Perform a simple set operation on the primary node, and then perform a get operation with the same key on the replica.
    You have now created an Amazon ElastiCache cluster using the Redis engine and configured a read replica.
     
    Review Questions
    Which of the following objects are good candidates to store in a cache? (Choose 3 answers)
  • Session state
  • Shopping cart
  • Product catalog
  • Bank account balance

Which of the following cache engine are supported by Amazon ElastiCache? (Choose 2 answers)

  • MySQL
  • Memcached
  • Redis
  • Couchbase

How many nodes can you add to an Amazon ElastiCache cluster running Memcached?

  • 1
  • 5
  • 20
  • 100

How many nodes can you add to an Amazon ElastiCache cluster running Redis?

  • 1
  • 5
  • 20
  • 100

An application currently uses Memcached to cache frequently used database queries. Which steps are required to migrate the application to use Amazon ElastiCache with minimal changes? (Choose 2 answers)

  • Recompile the application to use the Amazon ElastiCache libraries.
  • Update the configuration file with the endpoint for the Amazon ElastiCache cluster.
  • Configure a security group to allow access from the application servers.
  • Connect to the Amazon ElastiCache nodes using Secure Shell (SSH) and install the latest version of Memcached.

HOW can you back up data stored in Amazon ElastiCache running Redis? (Choose 2 answers)

  • Create an image of the Amazon Elastic Compute Cloud (Amazon EC2) instance.
  • Configure automatic snapshots to back up the cache environment every night.
  • Create a snapshot manually.
  • Redis clusters cannot be backed up.

How can you secure an Amazon ElastiCache cluster? (Choose 3 answers)

  • Change the Memcached root password.
  • Restrict Application Programming Interface (API) actions using AWS Identity and Access Management (IAM) policies.
  • Restrict network access using security groups.
  • Restrict network access using a network Access Control List (ACL).

You are working on a mobile gaming application and are building the leaderboard feature to track the top scores across millions of users. Which AWS services are best suited for this use case?

  • Amazon Redshift
  • Amazon ElastiCache using Memcached
  • Amazon ElastiCache using Redis
  • Amazon Simple Storage Service (S3)

You have built a large web application that uses Amazon ElastiCache using Memcached to store frequent query results. You plan to expand both the web fleet and the cache fleet multiple times over the next year to accommodate increased user traffic. How do you minimize the amount of changes required when a scaling event occurs?

  • Configure AutoDiscovery on the client side
  • Configure AutoDiscovery on the server side
  • Update the configuration file each time a new cluster
  • Use an Elastic Load Balancer to proxy the requests

Which cache engines does Amazon ElastiCache support? (Choose 2 answers)

  • Memcached
  • Redis
  • Membase
  • Couchbase
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