## Types of Load Balancers Security, Storage, Scaling, and High Availability in AWS In this article, I continue my AWS Certified Cloud Practitioner learning series by covering core AWS compute, storage, networking security, scalability, and availability concepts. These topics are extremely important from both exam and real‑world DevOps perspectives. Security Groups

Security Groups act as virtual firewalls that control inbound and outbound traffic for EC2 instances. Inbound RulesAllowing HTTP (TCP 80) from anywhere (0.0.0.0/0) enables users to view an EC2 instance in a web browser.If a Security Group is misconfigured, a timeout error typically occurs when trying to access the instance. Outbound RulesBy default, outbound rules allow IPv4 – All Traffic.This configuration gives the EC2 instance full outbound connectivity to anywhere. SSH AccessPort 22 (SSH) from anywhere is required to connect to the instance using any of the four AWS-supported connection methods after clicking Connect. Amazon EBS (Elastic Block Store)EBS volumes are network drives attached to EC2 instances. The data stored on them persists even after the instance is terminated.(Think of an EBS volume like a pen drive.) Root VolumeDelete on Termination is enabled by default.This can be checked under the instance’s storage settings. Additional EBS VolumesDelete on Termination is disabled by default (important for the exam).An EBS volume can be attached to only one instance at a time, but a single instance can have multiple EBS volumes attached. Availability Zone ScopeEBS volumes are AZ‑specific and can only be attached to EC2 instances in the same AZ. SnapshotsA snapshot is a backup of an EBS volume.Snapshots are used to move EBS volumes across AZs.Detaching the volume before taking a snapshot is not required, but it is recommended.Snapshots are stored at the region level, allowing movement across AZs.Snapshots can also be copied across regions for disaster recovery. Snapshot ArchiveSnapshots can be moved to an archive tier, which is 75% cheaper.Restoring archived snapshots takes 24–72 hours. Recycle Bin for EBS SnapshotsAllows recovery of accidentally deleted snapshots.Setup path:Recycle Bin → Create Retention Rule → Resource Type (EBS Snapshots) → Rule Lock Settings (Unlock)Retention period: 1 day to 1 year Fast Snapshot RestoreForces full initialization of a snapshot.Removes latency during first use.Example: Moving a Volume Across AZs Snapshots can also be copied to other regions for disaster recovery. EC2 Instance Store Used when high‑performance hardware disk is required.Delivers better I/O performance than EBS.Ephemeral storage – data is lost when the instance is stopped.Common use cases:BuffersCachesTemporary contentScratch data High risk of data loss.Backup and replication are the user’s responsibility. AMI (Amazon Machine Image)AMIs are customized images of EC2 instances. Purpose of AMIs:Include OS, software, configurations, monitoring, and licenses.New instances can be launched without repeated configuration.Helps to add your own software licenses (exam point).Faster boot and configuration time. AMI CharacteristicsTypes:Public AMIs (AWS-provided).Own AMIs (created and maintained by us).AWS Marketplace AMIs (third‑party, may be paid). AMI Creation FlowStart and customize instanceStop instance (for data integrity)Create AMI (EBS snapshots created automatically)Launch new instances from the AMI EC2 Image BuilderAutomatically builds, tests, and distributes AMIs.Automates image management.Used for VM or container image creation.Runs on a schedule.Free service. Flow:EC2 Image Builder → Builder EC2 Instance → New AMI → Test EC2 Instance → AMI distributed (multiple regions). Amazon EFS (Elastic File System)Fully managed network file system.Can be mounted on hundreds of EC2 instances.Works with Linux EC2 instances across multiple AZs.High availability and scalability.Expensive, pay‑per‑use, no capacity planning. EBS vs EFSEBS supports snapshots.EFS provides a shared file system across AZs. EFS‑IACost‑optimized storage class.Stores files that are infrequently accessed. Shared Responsibility Model – EC2 Storage AWS Responsibilities:InfrastructureData replication for EBS and EFSReplacing faulty hardwareZero‑day issues User Responsibilities:Backup and snapshot configurationData encryptionData stored on drivesUnderstanding risks of EC2 Instance Store AWS FSx (File Systems)Fully managed high‑performance file systems when EFS or S3 are not suitable.FSx for Windows File Server Native Microsoft Windows file systemSupports SMB and NTFSHighly reliable and scalableAccessible from AWS and on‑premises FSx for LustreHigh Performance Computing (HPC) Linux file systemUsed for ML, analytics, video processing, financial modelingScales to hundreds of GB/sMillions of IOPS with sub‑millisecond latency Scalability ConceptsVertical ScalabilityIncrease instance size (e.g., t2.micro → t2.small)Common for non‑distributed systems like databasesHardware limits apply Horizontal ScalabilityIncrease number of instancesUsed in distributed systemsCommon for web and modern applicationsImplemented using EC2 High AvailabilityApplication running in at least two AZs.Helps survive data lossTightly coupled with horizontal scaling Key DefinitionsScalability: Ability to handle increased load.Elasticity: Automatic scaling once system is scalable.Agility: Speed of resource provisioning. Load BalancersLoad Balancers distribute incoming traffic across multiple servers. BenefitsDistributes traffic evenly.Single DNS entry for applications.Health checks on instances.SSL termination.Managed by AWS (ELB). Load Balancers do not perform backend autoscaling — Auto Scaling Groups are required. Application Load Balancer:HTTP/HTTPS, gRPC, Layer 7, static DNSNetwork Load Balancer:TCP/UDP/TLS, high performance, static IP, Layer 4Gateway Load Balancer:GENEVE protocol, traffic inspection/firewalls, Layer 3Classic Load Balancer:Layer 4 and 7 (retired in 2023) Templates let you quickly answer FAQs or store snippets for re-use. as well , this person and/or