Que algoritmo o Amazon ELB usa para balancear a carga?

Question

Eu encontrei isso na documentação oficial do ELB

By default, a load balancer routes each request independently to the application instance with the smallest load.

mas um artigo no Newvem diz que o ELB suporta apenas o algoritmo Round Robin

Algorithms supported by Amazon ELB - Currently Amazon ELB only supports Round Robin (RR) and Session Sticky Algorithms.

Então qual é esse?

[1] link

[2] link

    

Answer 1

É uma contagem de pedidos baseada em HTTP (S), round robin para outros.

link

Before a client sends a request to your load balancer, it first resolves the load balancer's domain name with the Domain Name System (DNS) servers. The DNS server uses DNS round robin to determine which load balancer node in a specific Availability Zone will receive the request.

The selected load balancer node then sends the request to healthy instances within the same Availability Zone. To determine the healthy instances, the load balancer node uses either the round robin (for TCP connections) or the least outstanding request (for HTTP/HTTPS connections) routing algorithm. The least outstanding request routing algorithm favors back-end instances with the fewest connections or outstanding requests.

    

Answer 2

Depende do tipo de ELB usado. A AWS, ao longo do tempo, introduziu o ELB de aplicativos e o ELB de rede junto com o ELB clássico.

Application Load Balancers aplica regras de ouvinte e atribui a solicitação (HTTP / HTTPS) a um grupo de destino. Ele seleciona um alvo daquele grupo alvo usando o round robin routing algorithm

O nó

Network Load Balancers que recebe a conexão seleciona um destino de seu grupo de destino usando flow hash routing algorithm

Classic Load Balancers usa round robin routing algorithm para ouvintes TCP e least outstanding requests routing algorithm para ouvintes HTTP e HTTPS

.

TLDR;

The modern ELBs use round robin routing algorithm for HTTP/HTTPS requests and flow hash routing algorithm for TCP requests.

Classic ELB used round robin routing algorithm for TCP requests and least outstanding requests routing algorithm for HTTP and HTTPS requests

Fonte / Leitura adicional: link