Redis deployed in AWS - Connection time out from localhost SpringBoot app - amazon-web-services

Question

Small question regarding Redis deployed in AWS (not AWS Elastic Cache) and an issue connecting to it.
Here is the setup of the Redis deployed in AWS: (pasting only the Kubernetes StatefulSet and Service)
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: redis
spec:
serviceName: redis
replicas: 3
selector:
matchLabels:
app: redis
template:
metadata:
labels:
app: redis
spec:
initContainers:
- name: config
image: redis:7.0.5-alpine
command: [ "sh", "-c" ]
args:
- |
cp /tmp/redis/redis.conf /etc/redis/redis.conf
echo "finding master..."
MASTER_FDQN=`hostname -f | sed -e 's/redis-[0-9]\./redis-0./'`
if [ "$(redis-cli -h sentinel -p 5000 ping)" != "PONG" ]; then
echo "master not found, defaulting to redis-0"
if [ "$(hostname)" = "redis-0" ]; then
echo "this is redis-0, not updating config..."
else
echo "updating redis.conf..."
echo "slaveof $MASTER_FDQN 6379" >> /etc/redis/redis.conf
fi
else
echo "sentinel found, finding master"
MASTER="$(redis-cli -h sentinel -p 5000 sentinel get-master-addr-by-name mymaster | grep -E '(^redis-\d{1,})|([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})')"
echo "master found : $MASTER, updating redis.conf"
echo "slaveof $MASTER 6379" >> /etc/redis/redis.conf
fi
volumeMounts:
- name: redis-config
mountPath: /etc/redis/
- name: config
mountPath: /tmp/redis/
containers:
- name: redis
image: redis:7.0.5-alpine
command: ["redis-server"]
args: ["/etc/redis/redis.conf"]
ports:
- containerPort: 6379
name: redis
volumeMounts:
- name: data
mountPath: /data
- name: redis-config
mountPath: /etc/redis/
volumes:
- name: redis-config
emptyDir: {}
- name: config
configMap:
name: redis-config
volumeClaimTemplates:
- metadata:
name: data
spec:
accessModes: [ "ReadWriteOnce" ]
storageClassName: nfs-1
resources:
requests:
storage: 50Mi
---
apiVersion: v1
kind: Service
metadata:
name: redis
spec:
ports:
- port: 6379
targetPort: 6379
name: redis
selector:
app: redis
type: LoadBalancer
The pods are healthy, I can exec into it and perform operations fine. Here is the get all:
NAME READY STATUS RESTARTS AGE
pod/redis-0 1/1 Running 0 22h
pod/redis-1 1/1 Running 0 22h
pod/redis-2 1/1 Running 0 22h
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/redis LoadBalancer 192.168.45.55 10.51.5.2 6379:30315/TCP 26h
NAME READY AGE
statefulset.apps/redis 3/3 22h
Here is the describe of the service:
Name: redis
Namespace: Namespace
Labels: <none>
Annotations: <none>
Selector: app=redis
Type: LoadBalancer
IP Family Policy: SingleStack
IP Families: IPv4
IP: 192.168.22.33
IPs: 192.168.22.33
LoadBalancer Ingress: 10.51.5.2
Port: redis 6379/TCP
TargetPort: 6379/TCP
NodePort: redis 30315/TCP
Endpoints: 192.xxx:6379,192.xxx:6379,192.xxx:6379
Session Affinity: None
External Traffic Policy: Cluster
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal IPAllocated 68s metallb-controller Assigned IP ["10.51.5.2"]
Normal nodeAssigned 58s (x5 over 66s) metallb-speaker announcing from node "someaddress.com" with protocol "bgp"
Normal nodeAssigned 58s (x5 over 66s) metallb-speaker announcing from node "someaddress.com" with protocol "bgp"
I then try to connect to it, i.e. inserting some data with a very straightforward Spring Boot application. The application has no business logic, just trying to insert data.
Here are the relevant parts:
#Configuration
public class RedisConfiguration {
#Bean
public ReactiveRedisConnectionFactory reactiveRedisConnectionFactory() {
return new LettuceConnectionFactory("10.51.5.2", 30315);
}
#Repository
public class RedisRepository {
private final ReactiveRedisOperations<String, String> reactiveRedisOperations;
public RedisRepository(ReactiveRedisOperations<String, String> reactiveRedisOperations) {
this.reactiveRedisOperations = reactiveRedisOperations;
}
public Mono<RedisPojo> save(RedisPojo redisPojo) {
return reactiveRedisOperations.opsForValue().set(redisPojo.getInput(), redisPojo.getOutput()).map(__ -> redisPojo);
}
Each time I am trying to write the data, I am getting this exception:
2022-12-02T20:20:08.015+08:00 ERROR 1184 --- [ctor-http-nio-3] a.w.r.e.AbstractErrorWebExceptionHandler : [8f16a752-1] 500 Server Error for HTTP POST "/save"
org.springframework.data.redis.RedisConnectionFailureException: Unable to connect to Redis
at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory$ExceptionTranslatingConnectionProvider.translateException(LettuceConnectionFactory.java:1602) ~[spring-data-redis-3.0.0.jar:3.0.0]
Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException:
Error has been observed at the following site(s):
*__checkpoint ⇢ Handler com.redis.controller.RedisController#test(RedisRequest) [DispatcherHandler]
*__checkpoint ⇢ HTTP POST "/save" [ExceptionHandlingWebHandler]
Original Stack Trace:
at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory$ExceptionTranslatingConnectionProvider.translateException(LettuceConnectionFactory.java:1602) ~[spring-data-redis-3.0.0.jar:3.0.0]
Caused by: io.lettuce.core.RedisConnectionException: Unable to connect to 10.51.5.2/<unresolved>:30315
at io.lettuce.core.RedisConnectionException.create(RedisConnectionException.java:78) ~[lettuce-core-6.2.1.RELEASE.jar:6.2.1.RELEASE]
at io.lettuce.core.RedisConnectionException.create(RedisConnectionException.java:56) ~[lettuce-core-6.2.1.RELEASE.jar:6.2.1.RELEASE]
at io.lettuce.core.AbstractRedisClient.getConnection(AbstractRedisClient.java:350) ~[lettuce-core-6.2.1.RELEASE.jar:6.2.1.RELEASE]
at io.lettuce.core.RedisClient.connect(RedisClient.java:216) ~[lettuce-core-6.2.1.RELEASE.jar:6.2.1.RELEASE]
Caused by: io.netty.channel.ConnectTimeoutException: connection timed out: /10.51.5.2:30315
at io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe$1.run(AbstractNioChannel.java:261) ~[netty-transport-4.1.85.Final.jar:4.1.85.Final]
at io.netty.util.concurrent.PromiseTask.runTask(PromiseTask.java:98) ~[netty-common-4.1.85.Final.jar:4.1.85.Final]
This is particularly puzzling, because I am quite sure the code of the Spring Boot app is working. When I change the IP of return new LettuceConnectionFactory("10.51.5.2", 30315);: to
a regular Redis on my laptop ("localhost", 6379),
a dockerized Redis on my laptop,
a dockerized Redis on prem, all are working fine.
Therefore, I am quite puzzled what did I do wrong with the setup of this Redis in AWS.
What should I do in order to connect to it properly.
May I get some help please?
Thank you

Answer 1

By default, Redis binds itself to the IP addresses 127.0.0.1 and ::1 and does not accept connections against non-local interfaces. Chances are high that this is your main issue and you may want to review your redis.conf file to bind Redis to the interface you need or to the generic * -::*, as explained in the comments of the config file itself (which I have linked above).
With that being said, Redis also does not accept connections on non-local interfaces if the default user has no password - a security layer named Protected mode. Thus you should either give your default user a password or disable protected mode in your redis.conf file.
Not sure if this applies to your case but, as a side note, I would suggest to always avoid exposing Redis to the Internet.

Answer 2

You are mixing 2 things.
To enable this service for pods in different namespaces you do not need external load balancer, you can just try to use redis.namespace-name:6379 dns name and it will just work. Such dns is there for every service you create (but works only inside kubernetes)
Kubernetes will make sure that your traffic will be routed to proper pods (assuming there is more than one).
If you want to expose redis from outside of kubernetes then you need to make sure there is connectivity from the outside and then you need network load balancer that will forward traffic to your kubernetes service (in your case node port, so you need NLB with eks worker nodes: 30315 as a targets)
If your worker nodes have public IP and their SecurityGroups allow connecting to them directly, you could try to connect to worker node's IP directly just to test things out (without LB).
And regardless off yout setup you can always create proxy via kubectl
kubectl port-forward -n redisNS svc/redis 6379:6379
and connect from spring boot app to localhost:6379
How do you want to connect from app to redis in a final setup?