How to Install CRI-O on Ubuntu For Kubernetes?

In this article, I will help you to install CRI-O on Ubuntu for Kubernetes by following the simple steps I have mentioned below.

CRI-O is a lightweight container runtime used with the Kubernetes Container Runtime Interface (CRI).

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Here are the steps to install CRI-O on Ubuntu.

Step 1: Update Your System

To begin, you need first to verify that your system is up to date by performing the following commands:

sudo apt update
sudo apt upgrade -y

Step 2: Install Required Packages

Install the important CRI-O packages using this command:

sudo apt install -y software-properties-common
sudo add-apt-repository ppa:projectatomic/ppa
sudo apt update

Step 3: Install CRI-O

Use the command apt-get to install CRI-O

sudo apt install -y cri-o-1.19

You need to replace version 1.19 with your desired one for CRI-O. Use the command apt-cache policy cri-o to check all the available versions available.

Step 4: Start and Enable CRI-O

You need to start the CRI-O service and set it to start automatically on boot:

sudo systemctl start crio
sudo systemctl enable crio

Step 5: Configure Kubernetes to Use CRI-O

To use CRI-O as the container runtime, you need to modify the Kubernetes configuration file. Generally, this is done on each node in your Kubernetes cluster. Add the –container-runtime=remote parameter to the /etc/systemd/system/kubelet.service.d/10-kubeadm.conf file and specify the CRI-O socket:

sudo nano /etc/systemd/system/kubelet.service.d/10-kubeadm.conf

Include the following lines in the file:

Environment="KUBELET_EXTRA_ARGS=--container-runtime=remote --container-runtime-endpoint=/var/run/crio/crio.sock"

It’s time to save the file and exit the text editor.

Step 6: Restart Kubelet

Restart the kubelet service to apply the changes you have made:

sudo systemctl daemon-reload
sudo systemctl restart kubelet

Step 7: Verify Installation

You can check that CRI-O is up and running by running the following command:

sudo crictl info

And now It should display information about CRI-O in the JSON format.

{
  "status": {
    "conditions": [
      {
        "type": "RuntimeReady",
        "status": true,
        "reason": "",
        "message": ""
      },
      {
        "type": "NetworkReady",
        "status": false,
        "reason": "NetworkPluginNotReady",
        "message": "Network plugin returns error: No CNI configuration file in /etc/cni/net.d/. Has your network provider started?"
      }
    ]
  }
}

The CRI-O should be installed successfully and configured on your Ubuntu machine. Now, you can proceed further with configuring your Kubernetes cluster that can be used in CRI-O as the container runtime.

Read the Kubernetes tutorial for beginners guide for more information.

Conclusion

I hope this guide was helpful for you to install CRI-O on Ubuntu for Kubernetes. You can also refer to the official documentation for more details.

Let me know if you have any questions in the comment below.

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