Elastic Load Balancing | Application Load Balancer

Question 1

Can I privately access Elastic Load Balancing APIs from my Amazon Virtual Private Cloud (VPC) without using public IPs?

Application Load Balancer

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Answer 1

Yes, you can privately access Elastic Load Balancing APIs from your Amazon Virtual Private Cloud (VPC) by creating VPC Endpoints. With VPC Endpoints, the routing between the VPC and Elastic Load Balancing APIs is handled by the AWS network without the need for an Internet gateway, NAT gateway, or VPN connection. The latest generation of VPC Endpoints used by Elastic Load Balancing are powered by AWS PrivateLink, an AWS technology enabling the private connectivity between AWS services using Elastic Network Interfaces (ENI) with private IPs in your VPCs. To learn more about AWS PrivateLink, visit the AWS PrivateLink documentation.

Question 2

Which operating systems does an Application Load Balancer support?

Application Load Balancer

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Answer 2

An Application Load Balancer supports targets with any operating system currently supported by the Amazon EC2 service.

Question 3

Which protocols does an Application Load Balancer support?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 3

An Application Load Balancer supports load balancing of applications using HTTP and HTTPS (Secure HTTP) protocols.

Question 4

Is HTTP/2 Supported on an Application Load Balancer?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 4

Yes. HTTP/2 support is enabled natively on an Application Load Balancer. Clients that support HTTP/2 can connect to an Application Load Balancer over TLS.

Question 5

What TCP ports can I use to load balance?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 5

You can perform load balancing for the following TCP ports: 1-65535

Question 6

Is WebSockets supported on an Application Load Balancer?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 6

Yes. WebSockets and Secure WebSockets support is available natively and ready for use on an Application Load Balancer.

Question 7

Is Request tracing supported on an Application Load Balancer?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 7

Yes. Request tracing is enabled by default on your Application Load Balancer.

Question 8

Will my existing load balancers (Classic Load Balancers) have the same features and benefits of an Application Load Balancer?

Application Load Balancer

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Answer 8

While there is some overlap, we do not plan to maintain feature parity between the two types of load balancers. Application Load Balancers are the foundation of our application layer load-balancing platform for the future.

Question 9

Can I configure my Amazon EC2 instances to accept traffic only from my Application Load Balancers?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 9

Yes.

Question 10

Can I configure a security group for the front-end of an Application Load Balancer?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 10

Yes.

Question 11

Can I use the existing APIs that I use with my Classic Load Balancer with an Application Load Balancer?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 11

No. Application Load Balancers require a new set of APIs.

Question 12

How do I manage both Application and Classic Load Balancers simultaneously?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 12

The ELB Console will allow you to manage Application and Classic Load Balancers from the same interface. If you are using the CLI or an SDK, you will use a different ‘service’ for Application Load Balancers. For example, in the CLI you will describe your Classic Load Balancers using aws elb describe-load-balancers and your Application Load Balancers using aws elbv2 describe-load-balancers.

Question 13

Can I convert my Classic Load Balancer to an Application Load Balancer (and vice versa)?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 13

No, you cannot convert one load balancer type into another.

Question 14

Can I migrate to Application Load Balancer from Classic Load Balancer?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 14

Yes. You can migrate to Application Load Balancer from Classic Load Balancer using one of the options listed in this document.

Question 15

Can I use an Application Load Balancer as a Layer-4 load balancer?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 15

No. If you need Layer-4 features, you should use Network Load Balancer.

Question 16

Can I use a single Application Load Balancer for handling HTTP and HTTPS requests?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 16

Yes, you can add listeners for HTTP port 80 and HTTPS port 443 to a single Application Load Balancer.

Question 17

Can I get a history of Application Load Balancing API calls made on my account for security analysis and operational troubleshooting purposes?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 17

Yes. To receive a history of Application Load Balancing API calls made on your account, use AWS CloudTrail.

Question 18

Does an Application Load Balancer support HTTPS termination?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 18

Yes, you can terminate HTTPS connection on the Application Load Balancer. You must install an SSL certificate on your load balancer. The load balancer uses this certificate to terminate the connection and then decrypt requests from clients before sending them to targets.

Question 19

What are the steps to get a SSL certificate?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 19

You can either use AWS Certificate Manager to provision an SSL/TLS certificate or you can obtain the certificate from other sources by creating the certificate request, getting the certificate request signed by a CA, and then uploading the certificate either using AWS Certification Manager or the AWS Identity and Access Management (IAM) service.

Question 20

How does an Application Load Balancer integrate with AWS Certificate Manager (ACM)?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 20

An Application Load Balancer is integrated with AWS Certificate Management (ACM). Integration with ACM makes it very simple to bind a certificate to the load balancer thereby making the entire SSL offload process very easy. Purchasing, uploading, and renewing SSL/TLS certificates is a time-consuming manual and complex process. With ACM integration with Application Load Balancer, this whole process has been shortened to simply requesting a trusted SSL/TLS certificate and selecting the ACM certificate to provision it with the load balancer.

Question 21

Is back-end server authentication supported with an Application Load Balancer?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 21

No, only encryption is supported to the back-ends with an Application Load Balancer.

Question 22

How can I enable Server Name Indication (SNI) for my Application Load Balancer?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 22

SNI is automatically enabled when you associate more than one TLS certificate with the same secure listener on a load balancer. Similarly, SNI mode for a secure listener is automatically disabled when you have only one certificate associated to a secure listener.

Question 23

Can I associate multiple certificates for the same domain to a secure listener?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 23

Yes, you can associate multiple certificates for the same domain to a secure listener. For example, you can asoociate

(a) ECDSA and RSA certificates
(b) Certificates with different key sizes (e.g. 2K and 4K) for SSL/TLS certificates
(c) Single-Domain, Multi-Domain (SAN) and Wildcard certificates

Question 24

Is IPv6 supported with an Application Load Balancer?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 24

Yes, IPv6 is supported with an Application Load Balancer.

Question 25

How do you set up rules on an Application Load Balancer?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 25

You can configure rules for each of your listeners you configure for the load balancer. The rules include a condition and a corresponding action if the condition is satisfied. The condition will be a path URL path of a service (e.g. /img) and action is forward. Once you have set this up, the load balancer will use the rules to determine the service to which the request must be routed.

Question 26

Are there limits on the resources for an Application Load Balancer?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 26

Your AWS account has these limits for an Application Load Balancer.

Question 27

How can I protect my web applications behind a load balancer from web attacks?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 27

You can integrate your Application Load Balancer with AWS WAF, a web application firewall that helps protect web applications from attacks by allowing you to configure rules based on IP addresses, HTTP headers, and custom URI strings. Using these rules, AWS WAF can block, allow, or monitor (count) web requests for your web application. Please see AWS WAF Developer Guide for more information.

Question 28

Can I load balance to any arbitrary IP address?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 28

You can use any IP address from the load balancer’s VPC CIDR for targets within load balancer’s VPC and any IP address from RFC 1918 ranges (10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16) or RFC 6598 range (100.64.0.0/10) for targets located outside the load balancer’s VPC (for example, targets in Peered VPC, EC2-Classic and on-premises locations reachable over AWS Direct Connect or VPN connection).

Question 29

How can I load balance applications distributed across a VPC and on-premises location?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 29

There are various ways to achieve hybrid load balancing. If an application runs on targets distributed between a VPC and an on-premises location, you can add them to the same target group using their IP addresses. To migrate to AWS without impacting your application, gradually add VPC targets to the target group and remove on-premises targets from the target group. If you have two different applications such that the targets for one application are in a VPC and the targets for other applications are in on-premises location, you can put the VPC targets in one target group and the on-premises targets in another target group and use content based routing to route traffic to each target group. You can also use separate load balancers for VPC and on-premises targets and use DNS weighting to achieve weighted load balancing between VPC and on-premises targets.

Question 30

How can I load balance to EC2-Classic instances?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 30

You cannot load balance to EC2-Classic Instances when registering their Instance IDs as targets. However if you link these EC2-Classic instances to the load balancer’s VPC using ClassicLink and use the private IPs of these EC2-Classic instances as targets, then you can load balance to the EC2-Classic instances. If you are using EC2 Classic instances today with a Classic Load Balancer, you can easily migrate to an Application Load Balancer.

Question 31

How do I enable cross-zone load balancing in Application Load Balancer?

Application Load Balancer

Elastic Load Balancing | Compute

Answer 31

Cross-zone load balancing is already enabled by default in Application Load Balancer.