Lightsail container - connect to ElastiCache

Hello, and thank you for using Amazon Lightsail.

To do this, you'd want to use Lightsail's VPC Peering feature: https://lightsail.aws.amazon.com/ls/docs/en_us/articles/lightsail-how-to-set-up-vpc-peering-with-aws-resources

You would need the ElastiCache Redis cluster to be created in your account's default VPC. Then, after enabling VPC peering in the region within Lightsail, you should be able to connect to your Redis cluster, assuming your cluster's security group rules allow it.

I hope this helps!
-Max

I think the answer given by Max doesn't consider you're using Lightsail Container Service. What you probably need to do is make use of the peer-vpc cli command (see: https://awscli.amazonaws.com/v2/documentation/api/latest/reference/lightsail/peer-vpc.html) to peer the lightsail vpc with your default vpc. then add the lightsail cidr to the security group inbound rule as allowed source.