To install Longhorn in an air gapped environment, refer to this section.
For information on customizing Longhorn’s default settings, refer to this section.
For information on deploying Longhorn on specific nodes and rejecting general workloads for those nodes, refer to the section on taints and tolerations.
Each node in the Kubernetes cluster where Longhorn is installed must fulfill the following requirements:
A container runtime compatible with Kubernetes (Docker v1.13+, containerd v1.3.7+, etc.)
By default Longhorn installation requires a three-nodes cluster since the default replica count is 3 and the node level soft anti-affinity is disabled.
open-iscsi is installed, and the iscsid daemon is running on all the nodes. This is necessary, since Longhorn relies on iscsiadm on the host to provide persistent volumes to Kubernetes. For help installing open-iscsi, refer to this section.
The host filesystem supports the file extents feature to store the data. Currently we support:
curl, findmnt, grep, awk, blkid, lsblk must be installed.
waiting for pods to become ready (0/3)
all pods ready (3/3)
MountPropagation is enabled!
daemonset.apps "longhorn-environment-check" deleted
clean up complete
Pod Security Policy
Starting with v1.0.2, Longhorn is shipped with a default Pod Security Policy that will give Longhorn the necessary privileges to be able to run properly.
No special configuration is needed for Longhorn to work properly on clusters with Pod Security Policy enabled.
Notes on Mount Propagation
If your Kubernetes cluster was provisioned by Rancher v2.0.7+ or later, the MountPropagation feature is enabled by default.
If MountPropagation is disabled, Base Image feature will be disabled.
The command used to install open-iscsi differs depending on the Linux distribution.
For GKE, we recommend using Ubuntu as the guest OS image since it containsopen-iscsi already.
You may need to edit the cluster security group to allow SSH access.
For SUSE and openSUSE, use this command:
zypper install open-iscsi
For Debian and Ubuntu, use this command:
apt-get install open-iscsi
For RHEL, CentOS, and EKS with EKS Kubernetes Worker AMI with AmazonLinux2 image, use this command:
yum install iscsi-initiator-utils
Checking the Kubernetes Version
Use the following command to check your Kubernetes server version