# CRI-O crictl Tutorial

This tutorial will walk you through the creation of [Redis](https://redis.io/) server running in a [Pod](http://kubernetes.io/docs/user-guide/pods/) using [crictl](https://github.com/kubernetes-sigs/cri-tools/blob/master/docs/crictl.md)

It assumes you've already downloaded and configured `CRI-O`. If not, see [here for CRI-O](/install.md).
It also assumes you've set up CNI, and are using the default plugins as described [here](/contrib/cni/README.md). If you are using a different configuration, results may vary.

## Installation

This section will walk you through installing the following components:

* crictl - The CRI client for testing.

#### Get crictl

```
go get github.com/kubernetes-sigs/cri-tools/cmd/crictl
```

#### Ensure the CRI-O service is running

```
sudo crictl --runtime-endpoint unix:///var/run/crio/crio.sock version
```
```
Version:  0.1.0
RuntimeName:  cri-o
RuntimeVersion:  1.20.0-dev
RuntimeApiVersion:  v1alpha1
```

> to avoid setting `--runtime-endpoint` when calling crictl,
> you can run `export CONTAINER_RUNTIME_ENDPOINT=unix:///var/run/crio/crio.sock`
> or `cp crictl.yaml /etc/crictl.yaml` from this repo


## Pod Tutorial

Now that the `CRI-O` components have been installed and configured we are ready to create a Pod. This section will walk you through launching a Redis server in a Pod. Once the Redis server is running we'll use telnet to verify it's working, then we'll stop the Redis server and clean up the Pod.

### Creating a Pod

First we need to setup a Pod sandbox using a Pod configuration, which can be found in the `CRI-O` source tree:

```
cd $GOPATH/src/github.com/cri-o/cri-o
```

In case the file `/etc/containers/policy.json` does not exist on your filesystem, make sure that skopeo has been installed correctly. You can use a policy template provided in the CRI-O source tree, but it is insecure and it is not to be used on production machines:

```
sudo mkdir /etc/containers/
sudo cp test/policy.json /etc/containers
```


Next create the Pod and capture the Pod ID for later use:

```
POD_ID=$(sudo crictl runp test/testdata/sandbox_config.json)
```


Use the `crictl` command to get the status of the Pod:

```
sudo crictl inspectp --output table $POD_ID
```

Output:

```
ID: 3cf919ba84af36642e6cdb55e157a62407dec99d3cd319f46dd8883163048330
Name: podsandbox1
UID: redhat-test-crio
Namespace: redhat.test.crio
Attempt: 1
Status: SANDBOX_READY
Created: 2020-11-12 12:53:41.345961219 +0100 CET
IP Addresses: 10.85.0.7
Labels:
	group -> test
	io.kubernetes.container.name -> POD
Annotations:
	owner -> hmeng
	security.alpha.kubernetes.io/seccomp/pod -> unconfined
Info: # Redacted
```

### Create a Redis container inside the Pod

Use the `crictl` command to pull the Redis image, create a Redis container from a container configuration and attach it to the Pod created earlier, while capturing the container ID:

```
CONTAINER_ID=$(sudo crictl create $POD_ID test/testdata/container_redis.json test/testdata/sandbox_config.json)
```

The `crictl create` command  will take a few seconds to return because the Redis container needs to be pulled.

Start the Redis container:

```
sudo crictl start $CONTAINER_ID
```

Get the status for the Redis container:

```
sudo crictl inspect $CONTAINER_ID
```

Output:

```
ID: f70e2a71239c6724a897da98ffafdfa4ad850944098680b82d381d757f4bcbe1
Name: podsandbox1-redis
State: CONTAINER_RUNNING
Created: 32 seconds ago
Started: 16 seconds ago
Labels:
	tier -> backend
Annotations:
	pod -> podsandbox1
Info: # Redacted
```

### Test the Redis container

Fetch the Pod IP (can also be obtained via the `inspectp` output above):

```
POD_IP=$(sudo crictl inspectp --output go-template --template '{{.status.network.ip}}' $POD_ID)
```

Verify the Redis server is responding to `MONITOR` commands:

```
echo MONITOR | ncat $POD_IP 6379
```

Output:

```
+OK
```

#### Viewing the Redis logs

The Redis logs are logged to the stderr of the crio service, which can be viewed using `journalctl`:

```
sudo journalctl -u crio --no-pager
```

### Stop and delete the Redis container

```
sudo crictl stop $CONTAINER_ID
sudo crictl rm $CONTAINER_ID
```

Verify the container is gone via:

```
sudo crictl ps
```

### Stop and delete the Pod

```
sudo crictl stopp $POD_ID
sudo crictl rmp $POD_ID
```

Verify the pod is gone via:

```
sudo crictl pods
```
