Unable to connect to AWS ElastiCache cluster

[hudda10]

Bug Report

Current Behavior

I am using Spring cloudgateway and Spring data redis LettuceConnectionFactory
I have created a RedisMessageListenerContainer Bean like this below to listen to Key expiry events

   @Bean
    public RedisMessageListenerContainer redisMessageListenerContainer(LettuceConnectionFactory lettuceConnectionFactory) {
        RedisMessageListenerContainer container = new RedisMessageListenerContainer();
        container.setConnectionFactory(lettuceConnectionFactory);
        return container;
    }

My bean creation is failing because i am getting Connection related error with the AWS ElastiCache cluster using LettuceConnectionFactory.

Stacktrace below

Stack trace

io.netty.resolver.dns.DnsResolveContext$SearchDomainUnknownHostException: Failed to resolve 'test-cache-xxx-0001-002.test-cache-xxxx.cache.amazonaws.com' [A(1)] and search domain query for configured domains failed as well: [ai-ml-core.svc.cluster.local, svc.cluster.local, cluster.local, ec2.internal]
	at io.netty.resolver.dns.DnsResolveContext.finishResolve(DnsResolveContext.java:1151)
	at io.netty.resolver.dns.DnsResolveContext.tryToFinishResolve(DnsResolveContext.java:1098)
	at io.netty.resolver.dns.DnsResolveContext.query(DnsResolveContext.java:457)
	at io.netty.resolver.dns.DnsResolveContext.access$700(DnsResolveContext.java:69)
	at io.netty.resolver.dns.DnsResolveContext$2.operationComplete(DnsResolveContext.java:526)
	at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:590)
	at io.netty.util.concurrent.DefaultPromise.notifyListeners0(DefaultPromise.java:583)
	at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:559)
	at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:492)
	at io.netty.util.concurrent.DefaultPromise.setValue0(DefaultPromise.java:636)
	at io.netty.util.concurrent.DefaultPromise.setFailure0(DefaultPromise.java:629)
	at io.netty.util.concurrent.DefaultPromise.tryFailure(DefaultPromise.java:118)
	at io.netty.resolver.dns.DnsQueryContext.finishFailure(DnsQueryContext.java:380)
	at io.netty.resolver.dns.DnsQueryContext$5.run(DnsQueryContext.java:315)
	at io.netty.util.concurrent.PromiseTask.runTask(PromiseTask.java:98)
	at io.netty.util.concurrent.ScheduledFutureTask.run(ScheduledFutureTask.java:153)
	at io.netty.util.concurrent.AbstractEventExecutor.runTask(AbstractEventExecutor.java:173)
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:166)
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:469)
	at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:408)
	at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:994)
	at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	at java.base/java.lang.Thread.run(Unknown Source)
Caused by: io.netty.resolver.dns.DnsNameResolverTimeoutException: [7551: /172.20.0.10:53] DefaultDnsQuestion(test-cache-xxx-0001-002.test-cache-xxxx.cache.amazonaws.com. IN A) query '7551' via UDP timed out after 5000 milliseconds (no stack trace available)

Can somebody please help ?

additonal message

logger - io.lettuce.core.protocol.ConnectionWatchdog

Cannot reconnect to [test-cache-xxx-0001-002.test-cache-xxxx.cache.amazonaws.com/:6379]: Failed to resolve 'test-cache-xxx-0001-002.test-cache-xxxx.cache.amazonaws.com' [A(1)] and search domain query for configured domains failed as well: [ai-ml-core.svc.cluster.local, svc.cluster.local, cluster.local, ec2.internal]

And deleting the pod sometimes fixes the issue and the connection works just fine.

Environment

• spring data redis version - 3.3.2

[hudda10]

hi Team, can somebody please suggest what can be done here to resolve the issue ?

[tishun]

Hey @hudda10 ,

I would be happy to help, but this seems like a connectivity issue on the side of your application, in particular - DNS resolve issue.

Failed to resolve 'test-cache-xxx-0001-002.test-cache-xxxx.cache.amazonaws.com'

All the Lettuce driver could do is use the connection string provided to attempt to connect, but if the OS says that the address provided could not be resolved then:
a) either the address is wrong / misspelled
b) the container / physical machine could not resolve the domain name to an IP address (network settings)

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