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How to call Redis inside Kubernetes? Problems removing Old Redis service

Previously I had been experimenting with this command on Docker for Desktop Kubernetes

helm install my-release --set password=password bitnami/redis

I had issued the command helm uninstall my-release.

Now I am trying to make my todolistclient work inside (Docker for Desktop) Kubernetes with redis:

kubectl run redis --image=bitnami/redis:latest --replicas=1 --port=6379 --labels="ver=1,app=todo,env=proto" --env="REDIS_PASSWORD=password" --env="REDIS_REPLICATION_MODE=master" --env="REDIS_MASTER_PASSWORD=password"
kubectl run todolistclient --image=siegfried01/todolistclient:latest --replicas=3 --port=5000 --labels="ver=1,app=todo,env=proto"

When I look at the log for ToDoListClient, I see a stack trace indicating that it is failing to connect to the redis server with this error message:

System.AggregateException: One or more errors occurred. (No connection is available to service this operation: EVAL; SocketFailure on my-release-redis-master.default.svc.cluster.local:6379/Subscription, origin: Error, input-buffer: 0, outstanding: 0, last-read: 0s ago, last-write: 0s ago, unanswered-write: 9760s ago, keep-alive: 60s, pending: 0, state: Connecting, last-heartbeat: never, last-mbeat: -1s ago, global: 0s ago)

What is this my-release-redis-master.default.svc.cluster.local? This has been uninstalled and I’m not running that any more.

My C# code is connecting to Redis with

.AddDistributedRedisCache(options => { options.InstanceName = "OIDCTokens"; options.Configuration = "redis,password=password"; })

Just to be certain that I was indeed using the above code and specifically "redis", I recompiled my code and pushed to DockerHub again and I am getting the same error again.

So apparently there is something left over from the helm version of redis that is translating "redis" into "my-release-redis-master". How do I remove this so I can connect to my current redis?

Thanks

Siegfried

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2

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  1. Chosen as BEST ANSWER
    0

    The problem was that I had originally changed my source code to accommodate the name generated by helm: my-release-redis-master and later restored the code to just use the domain name redis.

    The confusion was from the fact that even though I was intending to compile and deploy (to Kubernetes) a debug version (which is the setting I had for Visual Studio), Visual studio was continuing to recompile the debug version but deploying that ancient release version with the bad domain name.

    The GUI for the Visual Studio 2019 publish dialog apparently is broken and won't let you deploy in debug mode. (I wish I could find the file where that publish dialog stored its settings so I could correct it with notepad). It would have been nice if I had received a warning indicating that it was not deploying my latest build.

    Arghya Sadhu's response was helpful because it gave me the confidence to say that this was not some weird feature of Kubernetes that causing my domain name to translated to the bogus my-release-redis-master.

    Thank you Arghya.

    So the solution was simple: recompile in release mode and deploy.

    Siegfried


  2. 0

    In the todolistclient application you are using my-release-redis-master.default.svc.cluster.local:6379/Subscription. This is the url of a service exposing redis pod. This is automatically created by helm release.

    If that is not desired then you need to change that url in todolistclient application to your redis service.
    You have deployed redis but have not created any service to expose redis, Hence you can not use a service url to connect to it unless you create it.

    So you have two options

    1. Use redis pod IP in the todolistclient application. This is not recomended because Pod IP changes when restarted.
    2. Create a service and then use that service url in todolistclient application.
    apiVersion: v1
kind: Service
metadata:
  name: redis-master
  labels:
    run: redis
spec:
  ports:
  - port: 6379
    targetPort: 6379
  selector:
    run: redis

    Here is a guide on how to deploy a guestbook application on kubernetes and connect to redis.

    One suggestion don’t use same labels for both todolistclient and redis

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