Skip to content

aws_notes.md

Latest commit

 

History

History
100 lines (52 loc) · 7.41 KB

aws_notes.md

File metadata and controls

100 lines (52 loc) · 7.41 KB
Raw

What are some different types of Routes available in AWS?

In Amazon Web Services (AWS), a route table is used to control the flow of network traffic within a Virtual Private Cloud (VPC) or a subnet. A route table contains a set of rules, called routes, that specify where network traffic should be directed. There are several different types of routes that can be added to a route table, including:

  • Local route: This is the default route that is automatically added to a route table. It directs all traffic for the VPC or subnet to the local network interface.

  • Internet gateway route: This route directs all traffic for the VPC or subnet to the Internet gateway, allowing instances in the VPC or subnet to access the Internet.

  • Virtual private gateway route: This route directs all traffic for the VPC or subnet to a virtual private gateway, allowing instances in the VPC or subnet to access a VPN connection.

  • Peering connection route: This route directs all traffic for the VPC or subnet to a VPC peering connection, allowing instances in the VPC or subnet to access another VPC.

  • NAT gateway route: This route directs all traffic for the VPC or subnet to a NAT gateway, allowing instances in a private subnet to access the Internet while preserving their private IP addresses.

  • VPN connection route: This route directs all traffic for the VPC or subnet to a VPN connection, allowing instances in the VPC or subnet to access another network over a VPN.

  • Transit Gateway route: This route directs all traffic for the VPC or subnet to a Transit Gateway, allowing instances in the VPC or subnet to access multiple VPCs and on-premises networks.

It is important to note that the traffic flow to each of these destinations, can be further fine-tuned via CIDR block, IP address or security group filtering

What are some different types of record that can be added to a DNS Zone?

There are several different types of records that can be added to a DNS zone, including:

  • A record (Address record): This record maps a hostname to an IPv4 address.

  • AAAA record (IPv6 address record): This record maps a hostname to an IPv6 address.

  • CNAME record (Canonical Name record): This record maps a hostname to another hostname.

  • MX record (Mail eXchange record): This record maps a domain name to a list of mail servers responsible for handling email for that domain.

  • NS record (Name Server record): This record maps a domain name to a list of name servers responsible for that domain.

  • PTR record (Pointer record): This record maps an IP address to a hostname.

  • SOA record (Start of Authority record): This record contains information about the DNS zone, including the primary name server, the email address of the domain administrator, and various settings for the zone.

  • TXT record (Text record): This record is used to store any text-based information, such as SPF data, DKIM, DMARC, etc.

It is important to note that each record type has different attributes and is used for specific purposes, and depending on the DNS provider there can be more record types available.

Explain CNAME record.

A CNAME (Canonical Name) record is a type of DNS record that maps an alias hostname to the true or canonical hostname. It is used to resolve a domain name to another domain name, rather than to an IP address.

When a client makes a request for the alias hostname, the DNS server returns the canonical hostname to the client, and the client then makes a request for the canonical hostname. This allows multiple hostnames to point to the same IP address or resource, which can be useful in several ways:

  • Redirection of traffic: By using a CNAME record, you can redirect traffic from one hostname to another without having to change the IP address of the server.
  • Load balancing: By using multiple CNAME records, you can distribute traffic across multiple servers for load balancing.
  • Service migration: By using a CNAME record, you can change the IP address of the server without affecting the hostname.
  • Separation of concerns: By using CNAME records, you can separate the management of the domain names from the management of the IP addresses.

It is important to note that CNAME records must always point to a hostname, never to an IP address. Also, CNAME records can not coexist with any other record types such as A, AAAA, MX, etc. on the same hostname.

CNAME records also have a few limitations:

  • They can not be used at the root of a domain.
  • They can not be used with certain services such as email servers (MX records)
  • Some providers or software may have additional limitations

CNAME records are used to create an alias for a domain or subdomain, pointing to another domain or subdomain. This allows you to use the same IP address and server resources for multiple domain names. This can be useful in situations such as load balancing, service migration, and separation of concerns.

What is AWS ELB? How does it work in Enterprise applications?

Amazon Web Services (AWS) Elastic Load Balancer (ELB) is a service that automatically distributes incoming traffic across multiple Amazon Elastic Compute Cloud (EC2) instances. It allows you to increase the availability and scalability of your application.

ELB can be used in several different ways to balance the load of incoming traffic:

  • Application Load Balancer (ALB): This type of ELB routes incoming traffic based on the content of the request, such as the hostname or the path. It is best suited for routing HTTP and HTTPS traffic.

  • Network Load Balancer (NLB): This type of ELB routes incoming traffic based on the IP protocol data, such as the IP address and the port. It is best suited for routing TCP and UDP traffic.

  • Classic Load Balancer: This is the original type of ELB and it routes incoming traffic based on either the IP protocol data or the application-level data. It is best suited for routing both HTTP and TCP traffic.

ELB can be used in high-traffic enterprise applications in several ways:

  • High availability: ELB automatically distributes incoming traffic across multiple instances, which can increase the availability of your application by providing failover capabilities.

  • Scalability: ELB can automatically scale the number of instances based on the incoming traffic, which can help to ensure that your application can handle high traffic loads.

  • Security: ELB can be integrated with AWS security services such as Amazon Certificate Manager (ACM) and AWS Identity and Access Management (IAM) to provide secure access to your application.

  • Monitoring and logging: ELB provides monitoring and logging capabilities, allowing you to track the performance of your application and to troubleshoot issues.

  • Autoscaling: ELB can be integrated with AWS Auto Scaling, which allows you to automatically scale the number of instances based on the incoming traffic and the performance of your application.

In summary, ELB is an AWS service that allows you to distribute incoming traffic across multiple instances to increase the availability and scalability of your application. It can be used in high-traffic enterprise applications to provide high availability, scalability, security, monitoring, and logging capabilities. Additionally, it can be integrated with other AWS services to provide additional functionality such as autoscaling and security.