# Configuring Redis using a ConfigMap
LLMS index: [llms.txt](/llms.txt)
---
This page provides a real world example of how to configure Redis using a ConfigMap and builds upon the [Configure a Pod to Use a ConfigMap](/docs/tasks/configure-pod-container/configure-pod-configmap/) task.
## Objectives
* Create a ConfigMap with Redis configuration values
* Create a Redis Pod that mounts and uses the created ConfigMap
* 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. It is recommended to run this tutorial on a cluster with at least two nodes that are not acting as control plane hosts. 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.
* The example shown on this page works with `kubectl` 1.14 and above.
* Understand [Configure a Pod to Use a ConfigMap](/docs/tasks/configure-pod-container/configure-pod-configmap/).
## Real World Example: Configuring Redis using a ConfigMap
Follow the steps below to configure a Redis cache using data stored in a ConfigMap.
First create a ConfigMap with an empty configuration block:
```shell
cat <./example-redis-config.yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: example-redis-config
data:
redis-config: ""
EOF
```
Apply the ConfigMap created above, along with a Redis pod manifest:
```shell
kubectl apply -f example-redis-config.yaml
kubectl apply -f https://raw.githubusercontent.com/kubernetes/website/main/content/en/examples/pods/config/redis-pod.yaml
```
Examine the contents of the Redis pod manifest and note the following:
* A volume named `config` is created by `spec.volumes[1]`
* The `key` and `path` under `spec.volumes[1].configMap.items[0]` exposes the `redis-config` key from the
`example-redis-config` ConfigMap as a file named `redis.conf` on the `config` volume.
* The `config` volume is then mounted at `/redis-master` by `spec.containers[0].volumeMounts[1]`.
This has the net effect of exposing the data in `data.redis-config` from the `example-redis-config`
ConfigMap above as `/redis-master/redis.conf` inside the Pod.
apiVersion: v1
kind: Pod
metadata:
name: redis
spec:
containers:
- name: redis
image: redis:8.0.2
command:
- redis-server
- "/redis-master/redis.conf"
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
Examine the created objects:
```shell
kubectl get pod/redis configmap/example-redis-config
```
You should see the following output:
```
NAME READY STATUS RESTARTS AGE
pod/redis 1/1 Running 0 8s
NAME DATA AGE
configmap/example-redis-config 1 14s
```
Recall that we left `redis-config` key in the `example-redis-config` ConfigMap blank:
```shell
kubectl describe configmap/example-redis-config
```
You should see an empty `redis-config` key:
```shell
Name: example-redis-config
Namespace: default
Labels:
Annotations:
Data
====
redis-config:
```
Use `kubectl exec` to enter the pod and run the `redis-cli` tool to check the current configuration:
```shell
kubectl exec -it pod/redis -- redis-cli
```
Check `maxmemory`:
```shell
127.0.0.1:6379> CONFIG GET maxmemory
```
It should show the default value of 0:
```shell
1) "maxmemory"
2) "0"
```
Similarly, check `maxmemory-policy`:
```shell
127.0.0.1:6379> CONFIG GET maxmemory-policy
```
Which should also yield its default value of `noeviction`:
```shell
1) "maxmemory-policy"
2) "noeviction"
```
Now let's add some configuration values to the `example-redis-config` ConfigMap:
apiVersion: v1
kind: ConfigMap
metadata:
name: example-redis-config
data:
redis-config: |
maxmemory 2mb
maxmemory-policy allkeys-lru
Apply the updated ConfigMap:
```shell
kubectl apply -f example-redis-config.yaml
```
Confirm that the ConfigMap was updated:
```shell
kubectl describe configmap/example-redis-config
```
You should see the configuration values we just added:
```shell
Name: example-redis-config
Namespace: default
Labels:
Annotations:
Data
====
redis-config:
----
maxmemory 2mb
maxmemory-policy allkeys-lru
```
Check the Redis Pod again using `redis-cli` via `kubectl exec` to see if the configuration was applied:
```shell
kubectl exec -it pod/redis -- redis-cli
```
Check `maxmemory`:
```shell
127.0.0.1:6379> CONFIG GET maxmemory
```
It remains at the default value of 0:
```shell
1) "maxmemory"
2) "0"
```
Similarly, `maxmemory-policy` remains at the `noeviction` default setting:
```shell
127.0.0.1:6379> CONFIG GET maxmemory-policy
```
Returns:
```shell
1) "maxmemory-policy"
2) "noeviction"
```
The configuration values have not changed because the Pod needs to be restarted to grab updated
values from associated ConfigMaps. Let's delete and recreate the Pod:
```shell
kubectl delete pod redis
kubectl apply -f https://raw.githubusercontent.com/kubernetes/website/main/content/en/examples/pods/config/redis-pod.yaml
```
Now re-check the configuration values one last time:
```shell
kubectl exec -it pod/redis -- redis-cli
```
Check `maxmemory`:
```shell
127.0.0.1:6379> CONFIG GET maxmemory
```
It should now return the updated value of 2097152:
```shell
1) "maxmemory"
2) "2097152"
```
Similarly, `maxmemory-policy` has also been updated:
```shell
127.0.0.1:6379> CONFIG GET maxmemory-policy
```
It now reflects the desired value of `allkeys-lru`:
```shell
1) "maxmemory-policy"
2) "allkeys-lru"
```
Clean up your work by deleting the created resources:
```shell
kubectl delete pod/redis configmap/example-redis-config
```
## What's next
* Learn more about [ConfigMaps](/docs/tasks/configure-pod-container/configure-pod-configmap/).
* Follow an example of [Updating configuration via a ConfigMap](/docs/tutorials/configuration/updating-configuration-via-a-configmap/).
