DevOps Use Case: Performing Redis maintenance in Kubernetes

Jul 23, 2018, by Karolis Rusenas

debug devops kubernetes maintenance redis tunnels

Nowadays it’s easy to run pretty much anything in Kubernetes clusters. But what about debugging these services? What if you need to quickly access a service that is normally not exposed to the internet or your intranet and is only accessible from within the cluster? Your service is like:

no loadbalancer

In this short article, I will demonstrate how to connect to a running Redis instance with an excellent and powerful Redis Commander GUI.

TL;DR

Prerequisites

Action!

Let’s deploy Redis (skip if you already have it running), from the cloned repository deploy it:

kubectl apply -f redis.yaml

It will create:

Now, install our tunnel based ingress controller into your cluster:

relay ingress init

This command:

You can check whether it’s running by:

$ kubectl get pods -n webrelay-ingress
NAME READY STATUS RESTARTS AGE
webrelay-69996f8d7c-522z8 1/1 Running 0 10s

Configure Redis Commander

Now, open redis-commander.yaml in your favorite code editor (mine is VSCode :) and edit several details.

If you are on a free tier, unfortunately, you won’t be able to choose a subdomain for your tunnel so you will need to create one first. Also, if you have chosen some different name for your Redis service, then update REDIS_HOSTS environment variable.

To create a tunnel, run:

$ relay tunnel create --group webrelay-ingress hello-ingress
2p4ptkh9vutgm8tqavigja.webrelay.io<---->http://127.0.0.1

Now, copy 2p4ptkh9vutgm8tqavigja.webrelay.io into the last, ingress section and to replace [REPLACE THIS WITH YOUR TUNNEL NAME]

apiVersion: v1
kind: Service
metadata:
labels:
name: redis-commander
name: redis-commander
spec:
ports:
- port: 8081
protocol: TCP
targetPort: 8081
selector:
app: redis-commander
type: NodePort
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: redis-commander
spec:
replicas: 1
selector:
matchLabels:
app: redis-commander
template:
metadata:
labels:
app: redis-commander
tier: backend
spec:
containers:
- name: redis-commander
image: rediscommander/redis-commander:latest
env:
- name: REDIS_HOSTS
value: redis:redis:6379
- name: REDIS_PORT
value: ""
ports:
- name: redis-commander
containerPort: 8081
---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
annotations:
kubernetes.io/ingress.class: webrelay # other ingress classes will be ignored
name: relay-ingress
spec:
rules:
- host: [REPLACE THIS WITH YOUR TUNNEL NAME]
http:
paths:
- path: /
backend:
serviceName: redis-commander
servicePort: 8081

Once you have finished editing, create it:

kubectl apply -f redis-commander.yaml

It should now be accessible from your browser:

Redis commander

Cool, yeah? Good luck with your other experiments!

cool? yeah

./wrap_up

To wrap up, the same strategy can be applied to other services like Prometheus or Grafana. You can create tunnels only when you need them, for example, while Grafana can always be connected, you would only want to have a look at Prometheus when you are not sure if service discovery is missing something or want to use raw queries.