# Redis Save Migrate & Resume (SMR) on Kubernetes

{% hint style="warning" %}
This example is outdated. Please look at our other examples.
{% endhint %}

## Setup

Let's first set up a sample redis database on k8s. Create a namespace called `cedana-examples` and install `redis-example.yaml` , which can be found here: <https://github.com/cedana/cedana-helm-charts/tree/main/examples>.

```bash
kubectl create namespace cedana-examples
kubectl apply -f redis-example.yaml
```

Now let's port-forward the service on 127.0.0.1 and connect to the database:

```bash
kubectl port-forward service/redis -n cedana-examples 6379:6379
redis-cli -h 127.0.0.1
```

Lets store some data in the db:

```bash
HSET 'user:001' first_name 'John' last_name 'doe' dob '12-JUN-1970'
HSET 'user:002' first_name 'David' last_name 'Bloom' dob '03-MAR-1981'
```

Listing all the pods in the `cedana-examples` namespace using the `/list` endpoint gives us all the information we need to do a checkpoint and restore.

```bash
curl -X GET -H 'Content-Type: application/json' -d '{
  "root": "'$ROOT'"
}' $CONTROLLER_URL:1324/list/cedana-examples
```

Great! Now its time to checkpoint the container. Lets set the necessary environment variables before we proceed, which were present in the output of the `/list` endpoint. The following variables should work on most default containerd clusters.

```bash
export CHECKPOINT_CONTAINER=redis \
export CHECKPOINT_SANDBOX=redis-6b5bcbb6b6-tdb4p \
export RESTORE_CONTAINER=redis-restore \
export RESTORE_SANDBOX=redis-restore-c6c794b64-h7ccs \
export NAMESPACE=cedana-examples \
export CONTROLLER_URL=localhost \
export ROOT=/run/containerd/runc/k8s.io \
export CHECKPOINT_PATH=/tmp/ckpt-redis
```

## Checkpoint

```bash
curl -X POST -H "Content-Type: application/json" -d '{
  "checkpoint_data": {
    "container_name": "'$CHECKPOINT_CONTAINER'",
    "sandbox_name": "'$CHECKPOINT_SANDBOX'",
    "namespace": "'$NAMESPACE'",
    "checkpoint_path": "'$CHECKPOINT_PATH'",
    "root": "'$ROOT'"
  }
}' http://$CONTROLLER_URL:1324/checkpoint
```

## Restore

Once this completes, we need a new pod to restore the redis checkpoint into - effectively acting as a sleeping pod that we morph into a restored redis pod. We do this to avoid colliding with Kubernetes' scheduling and state management, so the users have full control over when pods are being restored.

```bash
k apply -f redis-restore-example.yaml
```

Then, performing a restore is as simple as another `curl` call:

```bash
curl -X POST -H "Content-Type: application/json" -d '{
  "checkpoint_data": {
    "container_name": "'$RESTORE_CONTAINER'",
    "sandbox_name": "'$RESTORE_SANDBOX'",
    "namespace": "'$NAMESPACE'",
    "checkpoint_path": "'$CHECKPOINT_PATH'",
    "root": "'$ROOT'"
  }
}' http://$CONTROLLER_URL:1324/restore
```

Finally connect to redis-cli once again to check if the new restored container has the previously set data:

```bash
HGETALL user:001
HGETALL user:002
```


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