Configuring Redis using a ConfigMap [page]deterministic
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.
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* 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.
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* 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 <<EOF >./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.
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: <none> Annotations: <none>
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:
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: <none> Annotations: <none>
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 hav …(trimmed)