I just setup a new EKS cluster (latest version available, using three default AMI).

I deployed a Redis instance in it as a Kubernetes service and exposed it. I can access the Redis database through internal DNS like : mydatabase.redis (it's deployed in the redis namespace). In another pod I can connect to my Redis database, however sometimes the connection takes more than 10 seconds.

It's doesn't seem to be a DNS resolution issue as host mydatabase.redis responds immediately with the service IP address. However when I try to connect to it, for example: nc mydatabase.redis 6379 -v it sometimes connects instantly and sometimes takes more than 10 seconds.

All my services are impacted, I don't know why. I didn't change any settings in my cluster this a basic EKS cluster.

How can I debug this?