Introduction to Certificates

ELB supports two types of certificates. If you need an HTTPS listener, you need to bind a server certificate to it. To enable mutual authentication, you also need to bind a CA certificate to the listener.

Server certificate: used for SSL handshake negotiations if an HTTPS listener is used. Both the certificate content and private key are required.
CA certificate: issued by a certificate authority (CA) and used to verify the certificate issuer. If HTTPS mutual authentication is required, HTTPS connections can be established only when the client provides a certificate issued by a specific CA.

Precautions

A certificate can be used by multiple load balancers but only needs to be uploaded to each load balancer once.
You must specify a domain name for an SNI certificate. The domain name must be the same as that in the certificate. .
For each certificate type, a listener can have only one certificate by default, but a certificate can be bound to more than one listener. If SNI is enabled for the listener, multiple server certificates can be bound.
Only original certificates are supported. That is to say, you cannot encrypt your certificates.
You do not need to configure certificates for both shared load balancers and associated backend servers. If you configure a certificate for backend servers, HTTPS listeners cannot be added to the load balancer. In this case, you can add a TCP listener to transparently transmit HTTPS traffic to backend servers. This restriction does not apply to dedicated load balancers.
You can use self-signed certificates. However, note that self-signed certificates pose security risks. Therefore, it is recommended that you use certificates issued by third parties.
ELB supports certificates only in PEM format. If you have a certificate in any other format, you must convert it to a PEM-encoded certificate.
If a certificate has expired, you need to manually replace or delete it.