Configuring Redis using a ConfigMap
This page provides a real world example of how to configure Redis using a ConfigMap and builds upon the Configure Containers Using a ConfigMap task.
Objectives
- Create a ConfigMap.
- Create a pod specification using the ConfigMap.
- Create the pod.
- Verify that the configuration was correctly applied.
Before you begin
You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using Minikube, or you can use one of these Kubernetes playgrounds:
To check the version, enter kubectl version.
- Understand Configure Containers Using a ConfigMap.
Real World Example: Configuring Redis using a ConfigMap
You can follow the steps below to configure a Redis cache using data stored in a ConfigMap.
- Create a ConfigMap from the
docs/tutorials/configuration/configmap/redis/redis-configfile:
kubectl create configmap example-redis-config --from-file=https://k8s.io/docs/tutorials/configuration/configmap/redis/redis-config
kubectl get configmap example-redis-config -o yaml apiVersion: v1
data:
redis-config: |
maxmemory 2mb
maxmemory-policy allkeys-lru
kind: ConfigMap
metadata:
creationTimestamp: 2016-03-30T18:14:41Z
name: example-redis-config
namespace: default
resourceVersion: "24686"
selfLink: /api/v1/namespaces/default/configmaps/example-redis-config
uid: 460a2b6e-f6a3-11e5-8ae5-42010af00002- Create a pod specification that uses the config data stored in the ConfigMap:
apiVersion: v1
kind: Pod
metadata:
name: redis
spec:
containers:
- name: redis
image: kubernetes/redis:v1
env:
- name: MASTER
value: "true"
ports:
- containerPort: 6379
resources:
limits:
cpu: "0.1"
volumeMounts:
- mountPath: /redis-master-data
name: data
- mountPath: /redis-master
name: config
volumes:
- name: data
emptyDir: {}
- name: config
configMap:
name: example-redis-config
items:
- key: redis-config
path: redis.conf- Create the pod:
kubectl create -f https://k8s.io/docs/tutorials/configuration/configmap/redis/redis-pod.yamlIn the example, the config volume is mounted at /redis-master.
It uses path to add the redis-config key to a file named redis.conf.
The file path for the redis config, therefore, is /redis-master/redis.conf.
This is where the image will look for the config file for the redis master.
- Use
kubectl execto enter the pod and run theredis-clitool to verify that the configuration was correctly applied:
kubectl exec -it redis redis-cli
127.0.0.1:6379> CONFIG GET maxmemory
1) "maxmemory"
2) "2097152"
127.0.0.1:6379> CONFIG GET maxmemory-policy
1) "maxmemory-policy"
2) "allkeys-lru"What's next
- Learn more about ConfigMaps.