redis-cli connection to Amazon ElastiCache Redis cluster hangs up
I have installed and compiled Redis from source and am attempting to connect to an Amazon ElastiCache (Redis) cluster.
I can connect to the default localhost with no problem, but attempting to connect to an AWS endpoint causes what seems to be an infinite hangup.
With defaults:
$ redis-server /etc/redis.conf # daemonized, uses localhost
$ redis-cli ping
PONG
$ sudo service redis_6379 status
Redis is running (12919)
$ redis-cli shutdown # or sudo service redis_6379 stop
Now, here is an attempt to connect to the endpoint, copies from AWS documentation on the topic:
redis-cli -c -h my_example_endpoint_name.eaogs8.ng.0001.use1.cache.amazonaws.com -p 6379 ping
This hangs up infinitely without anything being issued to stderr/stdout.
(Please note this is an example endpoint name; I have verified I am using the primary endpoint listed at the AWS console.)
I suspect this may be related to the security group settings for the cluster on the AWS side but am not sure specifically what could/should be modified. I appreciate suggestions of what could be blocking the connection and can provide info on the cluster itself as needed.
Answer
I was also seeing the call to redis-cli hang up infinitely, but in my case it did not stem from incorrectly-configured security groups.
Instead, it occurred because I had created my Redis cluster with the 'Encryption in-transit' option set to 'Yes'. This meant my database endpoint needed to be accessed through an SSL tunnel, which redis-cli does not do.
For my application, encryption in-transit wasn't actually necessary so I created a new Redis cluster with that option not selected. More details on what you need to do differently when using in-transit encryption can be found here: https://aws.amazon.com/premiumsupport/knowledge-center/elasticache-connect-redis-node/