<p>I have installed containerd 1.5.4 by following below steps in CentOS 7.9:</p>
<pre><code>wget -c https://github.com/containerd/containerd/releases/download/v1.5.4/containerd-1.5.4-linux-amd64.tar.gz
tar -zxvf containerd-1.5.4-linux-amd64.tar.gz -C /
mkdir -p /etc/containerd
containerd config default &gt; /etc/containerd/config.toml
</code></pre>
<p>I have followed the docs from <a href="https://kubernetes.io/docs/setup/production-environment/container-runtimes/" rel="nofollow noreferrer">here</a> and also created the config according to them. But when I try to start containerd:</p>
<pre><code>[root@iZuf62lgwih3vksz3640gnZ sysctl.d]# systemctl start containerd
Failed to start containerd.service: Unit not found.
</code></pre>
<p>What should I do to fix this problem?</p>

Dolphin
<p>The main issue is that you are only copying binary files, you are not creating any systemd service.</p>
<p>Be careful when using <code>-C /</code> flag with the <code>tar</code> command. On my CentOS 7 machine, two first commands:</p>
<pre><code>wget -c https://github.com/containerd/containerd/releases/download/v1.5.4/containerd-1.5.4-linux-amd64.tar.gz
tar -zxvf containerd-1.5.4-linux-amd64.tar.gz -C /
</code></pre>
<p>led to overwrite the <code>/bin</code> directory which destroyed the OS.</p>
<p>Back to the question, it seems like you are mixing two different instructions for installing <code>containerd</code> package. The <a href="https://kubernetes.io/docs/setup/production-environment/container-runtimes/" rel="nofollow noreferrer">instructions</a> from official Kubernetes wiki that you mentioned in your question are pretty-forward and good to follow. Try them:</p>
<p>Step 1. Install the containerd.io package from the official Docker repositories:</p>
<pre><code>yum install -y yum-utils
yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
yum install -y containerd.io
</code></pre>
<p>Step 2. Configure containerd:</p>
<pre><code>sudo mkdir -p /etc/containerd
containerd config default | sudo tee /etc/containerd/config.toml
</code></pre>
<p>Step 3. Restart containerd:</p>
<pre><code>systemctl restart containerd
</code></pre>
