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LH can be installed on a Kubernetes cluster in several ways: Rancher catalog app, kubectl or Helm. In this guide we will focus on the installation via Helm chart, which must of course be installed. However, for further details, please refer to the official guide.

Requirements

Each node in the Kubernetes cluster where LH is installed must fulfill the following requirements:

  1. A container runtime compatible with Kubernetes (Docker v1.13+, containerd v1.3.7+, etc.).
  2. Kubernetes v1.1618+ (recommend Kubernetes v1.17+).

  3. open-iscsi is installed, and the iscsid daemon is running on all the nodes. This is necessary, since LH relies on iscsiadm on the host to provide persistent volumes to Kubernetes.

    Code Block
    languagebash
    titleInstall iscsi
    collapsetrue
    # If not present, launch the command
$ sudo yum --setopt=tsflags=noscripts install iscsi-initiator-utils -y
# Then enable and start the daemon
$ sudo systemctl enable iscsid
$ sudo systemctl start iscsid


  4. RWX support requires that each node has a NFSv4 client installed.

    Code Block
    languagebash
    titleInstall nfs-utils
    collapsetrue
    # If not present, launch the command
$ sudo yum install nfs-utils -y


  5. The host filesystem supports the file extents feature to store the data. Currently we support ext4 and XFS.

    Code Block
    languagebash
    titleFilesystem type
    collapsetrue
    # Check that the database type is "xfs" or "ext4"
$ df -T
$ df -ThTh | grep /dev/vd
Filesystem     Type      Size  Used Avail Use% Mounted on
/dev/vda1      xfs        80G  5.0G   76G   7% /


  6. curl, findmnt, grep, awk, blkid, lsblk must be installed.

  7. Mount propagation must be enabled.

    Code Block
    languagebash
    titleMount propagation
    collapsetrue
    # Insert the following lines into the file "/etc/systemd/system/docker.service.d/mount_propagation_flags.conf"
[Service]
MountFlags=shared

# Then restart the service
$ sudo systemctl daemon-reload
$ sudo systemctl restart docker.service


A script has been written to help you gather enough information about the factors (note jq maybe required to be installed locally prior to running env check script). To run script

Code Block
languagebash
titleCheck Script
collapsetrue
curl -sSfL https://raw.githubusercontent.com/longhorn/longhorn/v1.3.0/scripts/environment_check.sh | bash
[INFO]  Required dependencies are installed.
[INFO]  Waiting for longhorn-environment-check pods to become ready (0/0)...
[INFO]  All longhorn-environment-check pods are ready (3/3).
[INFO]  Required packages are installed.
[INFO]  MountPropagation is enabled.
[INFO]  Cleaning up longhorn-environment-check pods...
[INFO]  Cleanup completed.

Installation with Helm

Add the LH Helm repository and Fetch and fetch the latest charts from the repository

...

Code Block
languagebash
titleInstall LH
kubectl create namespace# Use the --create-namespace flag, if the namespace does not exist
$ helm install longhorn longhorn/longhorn --namespace longhorn-system [--create-namespace]

# Upgrade or uninstall chart
$ helm upgrade <chart_name> longhorn/longhorn -n longhorn-system
$ helm uninstall <chart_name> -n longhorn-system

The initial settings for Longhorn can be customized using Helm options or by editing the deployment configuration file. To obtain a copy of the values.yaml file

Code Block
languagebash
titleCustomize LH
collapsetrue
$ helm show values longhorn/longhorn > values.yaml
# Modify the default settings in the YAML file and then add flag "--values values.yaml" in the install command
$ helm install longhorn longhorn/longhorn --namespace longhorn-system --values values.yaml

To confirm that the deployment succeeded, run

Code Block
languagebash
titleVerify installation
collapsetrue
$ kubectl -n longhorn-system get pod
NAME                                        READY   STATUS    RESTARTS   AGE
csi-attacher-5f46994f7-4t8dn                1/1     Running   RESTARTS0          AGE82s
compatible-csi-attacher-d9fb48bcf5f46994f7-2rzmbl6gjl      1/1     Running     1/1     Running   0          8m58s81s
csi-attacher-78bf9b98985f46994f7-grn2ctkz4p                1/1     Running   0          81s
csi-provisioner-6ccbfbf86f-78gvc            1/1     Running   0          32s81s
csi-attacherprovisioner-78bf9b9898-lfzvq   6ccbfbf86f-psrt2            1/1     Running   0          81s
csi-provisioner-6ccbfbf86f-zccxt            1/1     Running   0          81s
csi-resizer-6dd8bd4c97-462sd                1/1     Running   0          8m59s81s
csi-attacherresizer-78bf9b98986dd8bd4c97-r64svjls9w                1/1     Running   0          81s
csi-resizer-6dd8bd4c97-kn5bb                1/1     Running   0          33s81s
csi-provisionersnapshotter-8599d5bf9786f65d8bc-c8r792968g             1/1     Running   0          81s
csi-snapshotter-86f65d8bc-8ptsr             1/1     Running   0          33s81s
csi-provisionersnapshotter-8599d5bf9786f65d8bc-fc5pzvgrr4             1/1     Running   0          81s
engine-image-ei-fa2dfbf0-fd4kj              1/1     Running   0          33s109s
csiengine-image-provisionerei-8599d5bf97fa2dfbf0-p9pslhcv8p              1/1     Running   0          109s
engine-image-ei-fa2dfbf0-q7qdt              1/1     Running   0          8m59s109s
csiinstance-resizermanager-586665f745e-b7p6h23cd97d9                 1/1     Running   0          109s
instance-manager-e-275b5e10                 1/1     Running   0          8m59s100s
csiinstance-resizermanager-586665f745e-kgdxsfdd447fd                 1/1     Running   0          105s
instance-manager-r-17584df4                 1/1     Running   0          33s109s
csiinstance-resizermanager-586665f745r-vsvvq2a170a69                 1/1     Running   0          100s
instance-manager-r-544a80b6                 1/1     Running   0          33s104s
enginelonghorn-imagecsi-ei-e10d6bf5-pv2s6plugin-5qmqv                   12/12     Running   0          80s
longhorn-csi-plugin-hqpcm                   2/2     Running   0          9m30s80s
instancelonghorn-managercsi-eplugin-379373afsb5nf                   12/12     Running   0          80s
longhorn-driver-deployer-6db849975f-cjjnj   1/1     Running   0          8m41s2m15s
instancelonghorn-manager-r-101f13ba4k7p7                      1/1     Running   1          2m15s
longhorn-manager-pvd2b                      1/1     Running   0          8m40s2m15s
longhorn-csi-plugin-7v2dcmanager-rh99r                      41/41     Running   1          2m15s
longhorn-ui-6f547c964-7vbl4                 1/1     Running   0          2m15s

Accessing the UI

Info
titlePrerequisites

These instructions assume that LH and a ingress controller (i.e. Nginx, Traefik) are installed, of course.

Once LH has been installed in your Kubernetes cluster, you can access the UI dashboard. First let's see which service we need to connect our ingress controller to. So let's use

Code Block
languagebash
titleLonghorn service
collapsetrue
# The service we are interested in is 8m59s
"longhorn-driver-deployer-775897bdf6-k4sfdfrontend"
$ kubectl -n longhorn-system get svc
NAME          1/1     Running TYPE        CLUSTER-IP    0  EXTERNAL-IP   PORT(S)     10mAGE
longhorn-manager-79xgjbackend    ClusterIP   10.233.28.215   <none>        9500/TCP    1/124h
longhorn-frontend   ClusterIP  Running 10.233.63.167   <none>        80/TCP 0     24h

At this point we can build the ingress resource, as usual

Code Block
languageyml
titleIngress resource
collapsetrue
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: 9m50s
longhorn-ui-9fbb5445-httqflonghorn-ingress
  namespace: longhorn-system
spec:
#  tls:		# Uncomment this part if you have the secret
#  - hosts:
#    - <host>
#    secretName: <secret>
  rules:
  - host: <host>
    http:
      paths:
      - path: 0/1/
        pathType: Prefix
        backend:
          service:
             Runningname: longhorn-frontend
            port:
  0             33snumber: 80

LH dashboardImage Added