Longhorn CSI on K3s
In this section, you’ll learn how to install Longhorn on a K3s Kubernetes cluster. K3s is a fully compliant Kubernetes distribution that is easy to install, using half the memory, all in a binary of less than 50mb.
iscsiadminstalled on the node.
Longhorn v0.7.0 and above support k3s v0.10.0 and above only by default.
If you want to deploy these new Longhorn versions on versions before k3s v0.10.0, you need to set
<data-dir>/agent/kubelet for the Deployment
data-dir is a
k3s arg and it can be set when you launch a k3s server. By default it is
This error is due to Longhorn cannot detect where is the root dir setup for Kubelet, so the CSI plugin installation failed.
You can override the root-dir detection by setting environment variable
KUBELET_ROOT_DIR in https://github.com/longhorn/longhorn/blob/v1.4.0/deploy/longhorn.yaml.
For K3S prior to v0.10.0
ps aux | grep k3s and get argument
-d on k3s node.
$ ps uax | grep k3s root 4160 0.0 0.0 51420 3948 pts/0 S+ 00:55 0:00 sudo /usr/local/bin/k3s server --data-dir /opt/test/kubelet root 4161 49.0 4.0 259204 164292 pts/0 Sl+ 00:55 0:04 /usr/local/bin/k3s server --data-dir /opt/test/kubelet
You will find
data-dir in the cmdline of proc
k3s. By default it is not set and
/var/lib/rancher/k3s will be used. Then joining
/agent/kubelet you will get the
root-dir. So the default
root-dir for K3S is
If K3S is using a configuration file, you would need to check the configuration file to locate the
For K3S v0.10.0+
It is always
K3S now sets its kubelet directory to
/var/lib/kubelet. See the K3S release comment for details.
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