Longhorn is a storage manager for kubernetes, based around local storage on the nodes. In that, it is somewhat like Hadoop, which is also designed for machines with both processing and storage.
https://longhorn.io/docs/1.7.2/deploy/install/#using-the-environment-check-script Firstly, Longhorn have provides a script to check if your system meets the requirements. So let us try to run this
[aabl@k8smaster1 ~]$ curl -sSfL https://raw.githubusercontent.com/longhorn/longhorn/v1.7.2/scripts/environment_check.sh | bash
[INFO] Required dependencies 'kubectl jq mktemp sort printf' are installed.
[INFO] All nodes have unique hostnames.
[INFO] Waiting for longhorn-environment-check pods to become ready (0/3)...
[INFO] Waiting for longhorn-environment-check pods to become ready (0/3)...
[INFO] All longhorn-environment-check pods are ready (3/3).
[INFO] MountPropagation is enabled
[INFO] Checking kernel release...
[INFO] Checking iscsid...
[ERROR] kernel module iscsi_tcp is not enabled on k8snode2.k8s.askov.net
[ERROR] Neither iscsid.service nor iscsid.socket is running on k8smaster1.k8s.askov.net
[ERROR] kernel module iscsi_tcp is not enabled on k8snode1.k8s.askov.net
[INFO] Checking multipathd...
[INFO] Checking packages...
[ERROR] nfs-utils is not found in k8snode2.k8s.askov.net.
[ERROR] nfs-utils is not found in k8smaster1.k8s.askov.net.
[ERROR] nfs-utils is not found in k8snode1.k8s.askov.net.
[INFO] Checking nfs client...
[INFO] Cleaning up longhorn-environment-check pods...
[INFO] Cleanup completed.
[aabl@k8smaster1 ~]$
So we lack the kernel module iscsi_tcp and the tool nfs-utils.
Lets install the nfs-util tool
[aabl@k8smaster1 ~]$ sudo dnf install nfs-utils
Last metadata expiration check: 0:10:50 ago on Sat Nov 2 12:22:14 2024.
Dependencies resolved.
===================================================================================================================================================================================================================================
Package Architecture Version Repository Size
===================================================================================================================================================================================================================================
Installing:
nfs-utils x86_64 1:2.5.4-26.el9_4 baseos 429 k
Installing dependencies:
gssproxy x86_64 0.8.4-6.el9 baseos 108 k
keyutils x86_64 1.6.3-1.el9 baseos 72 k
libev x86_64 4.33-5.el9 baseos 52 k
libnfsidmap x86_64 1:2.5.4-26.el9_4 baseos 59 k
libverto-libev x86_64 0.3.2-3.el9 baseos 13 k
rpcbind x86_64 1.2.6-7.el9 baseos 56 k
sssd-nfs-idmap x86_64 2.9.4-6.el9_4.1 baseos 41 k
Transaction Summary
===================================================================================================================================================================================================================================
Install 8 Packages
Total download size: 830 k
Installed size: 2.1 M
Is this ok [y/N]: y
Downloading Packages:
(1/8): libverto-libev-0.3.2-3.el9.x86_64.rpm 91 kB/s | 13 kB 00:00
(2/8): rpcbind-1.2.6-7.el9.x86_64.rpm 367 kB/s | 56 kB 00:00
(3/8): libev-4.33-5.el9.x86_64.rpm 323 kB/s | 52 kB 00:00
(4/8): sssd-nfs-idmap-2.9.4-6.el9_4.1.x86_64.rpm 969 kB/s | 41 kB 00:00
(5/8): gssproxy-0.8.4-6.el9.x86_64.rpm 2.3 MB/s | 108 kB 00:00
(6/8): nfs-utils-2.5.4-26.el9_4.x86_64.rpm 6.2 MB/s | 429 kB 00:00
(7/8): libnfsidmap-2.5.4-26.el9_4.x86_64.rpm 1.2 MB/s | 59 kB 00:00
(8/8): keyutils-1.6.3-1.el9.x86_64.rpm 1.8 MB/s | 72 kB 00:00
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Total 1.7 MB/s | 830 kB 00:00
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
Preparing : 1/1
Installing : libnfsidmap-1:2.5.4-26.el9_4.x86_64 1/8
Installing : keyutils-1.6.3-1.el9.x86_64 2/8
Installing : libev-4.33-5.el9.x86_64 3/8
Installing : libverto-libev-0.3.2-3.el9.x86_64 4/8
Installing : gssproxy-0.8.4-6.el9.x86_64 5/8
Running scriptlet: gssproxy-0.8.4-6.el9.x86_64 5/8
Running scriptlet: rpcbind-1.2.6-7.el9.x86_64 6/8
Installing : rpcbind-1.2.6-7.el9.x86_64 6/8
Running scriptlet: rpcbind-1.2.6-7.el9.x86_64 6/8
Created symlink /etc/systemd/system/multi-user.target.wants/rpcbind.service → /usr/lib/systemd/system/rpcbind.service.
Created symlink /etc/systemd/system/sockets.target.wants/rpcbind.socket → /usr/lib/systemd/system/rpcbind.socket.
Running scriptlet: nfs-utils-1:2.5.4-26.el9_4.x86_64 7/8
Installing : nfs-utils-1:2.5.4-26.el9_4.x86_64 7/8
Running scriptlet: nfs-utils-1:2.5.4-26.el9_4.x86_64 7/8
Installing : sssd-nfs-idmap-2.9.4-6.el9_4.1.x86_64 8/8
Running scriptlet: sssd-nfs-idmap-2.9.4-6.el9_4.1.x86_64 8/8
Verifying : libverto-libev-0.3.2-3.el9.x86_64 1/8
Verifying : rpcbind-1.2.6-7.el9.x86_64 2/8
Verifying : libev-4.33-5.el9.x86_64 3/8
Verifying : sssd-nfs-idmap-2.9.4-6.el9_4.1.x86_64 4/8
Verifying : gssproxy-0.8.4-6.el9.x86_64 5/8
Verifying : nfs-utils-1:2.5.4-26.el9_4.x86_64 6/8
Verifying : libnfsidmap-1:2.5.4-26.el9_4.x86_64 7/8
Verifying : keyutils-1.6.3-1.el9.x86_64 8/8
Installed:
gssproxy-0.8.4-6.el9.x86_64 keyutils-1.6.3-1.el9.x86_64 libev-4.33-5.el9.x86_64 libnfsidmap-1:2.5.4-26.el9_4.x86_64 libverto-libev-0.3.2-3.el9.x86_64 nfs-utils-1:2.5.4-26.el9_4.x86_64 rpcbind-1.2.6-7.el9.x86_64
sssd-nfs-idmap-2.9.4-6.el9_4.1.x86_64
Complete!
[aabl@k8smaster1 ~]$
And we are now missing iscsi-initiator-utils
[aabl@k8smaster1 ~]$ curl -sSfL https://raw.githubusercontent.com/longhorn/longhorn/v1.7.2/scripts/environment_check.sh | bash
[INFO] Required dependencies 'kubectl jq mktemp sort printf' are installed.
[INFO] All nodes have unique hostnames.
[INFO] Waiting for longhorn-environment-check pods to become ready (0/3)...
[INFO] All longhorn-environment-check pods are ready (3/3).
[INFO] MountPropagation is enabled
[INFO] Checking kernel release...
[INFO] Checking iscsid...
E1102 12:33:17.729236 44731 websocket.go:296] Unknown stream id 1, discarding message
[ERROR] kernel module iscsi_tcp is not enabled on k8snode2.k8s.askov.net
[ERROR] Neither iscsid.service nor iscsid.socket is running on k8smaster1.k8s.askov.net
[ERROR] kernel module iscsi_tcp is not enabled on k8snode1.k8s.askov.net
[INFO] Checking multipathd...
[INFO] Checking packages...
[ERROR] nfs-utils is not found in k8snode2.k8s.askov.net.
[ERROR] iscsi-initiator-utils is not found in k8smaster1.k8s.askov.net.
[ERROR] nfs-utils is not found in k8snode1.k8s.askov.net.
[INFO] Checking nfs client...
[INFO] Cleaning up longhorn-environment-check pods...
[INFO] Cleanup completed.
[aabl@k8smaster1 ~]$
So we install that.
[aabl@k8smaster1 ~]$ sudo dnf install iscsi-initiator-utils
Last metadata expiration check: 0:12:51 ago on Sat Nov 2 12:22:14 2024.
Dependencies resolved.
===================================================================================================================================================================================================================================
Package Architecture Version Repository Size
===================================================================================================================================================================================================================================
Installing:
iscsi-initiator-utils x86_64 6.2.1.9-1.gita65a472.el9 baseos 383 k
Installing dependencies:
iscsi-initiator-utils-iscsiuio x86_64 6.2.1.9-1.gita65a472.el9 baseos 80 k
isns-utils-libs x86_64 0.101-4.el9 baseos 100 k
Transaction Summary
===================================================================================================================================================================================================================================
Install 3 Packages
Total download size: 563 k
Installed size: 2.1 M
Is this ok [y/N]: y
Downloading Packages:
(1/3): iscsi-initiator-utils-iscsiuio-6.2.1.9-1.gita65a472.el9.x86_64.rpm 363 kB/s | 80 kB 00:00
(2/3): isns-utils-libs-0.101-4.el9.x86_64.rpm 446 kB/s | 100 kB 00:00
(3/3): iscsi-initiator-utils-6.2.1.9-1.gita65a472.el9.x86_64.rpm 1.4 MB/s | 383 kB 00:00
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Total 1.1 MB/s | 563 kB 00:00
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
Preparing : 1/1
Installing : isns-utils-libs-0.101-4.el9.x86_64 1/3
Installing : iscsi-initiator-utils-iscsiuio-6.2.1.9-1.gita65a472.el9.x86_64 2/3
Running scriptlet: iscsi-initiator-utils-iscsiuio-6.2.1.9-1.gita65a472.el9.x86_64 2/3
Created symlink /etc/systemd/system/sockets.target.wants/iscsiuio.socket → /usr/lib/systemd/system/iscsiuio.socket.
Installing : iscsi-initiator-utils-6.2.1.9-1.gita65a472.el9.x86_64 3/3
Running scriptlet: iscsi-initiator-utils-6.2.1.9-1.gita65a472.el9.x86_64 3/3
Created symlink /etc/systemd/system/sysinit.target.wants/iscsi-starter.service → /usr/lib/systemd/system/iscsi-starter.service.
Created symlink /etc/systemd/system/sockets.target.wants/iscsid.socket → /usr/lib/systemd/system/iscsid.socket.
Created symlink /etc/systemd/system/sysinit.target.wants/iscsi-onboot.service → /usr/lib/systemd/system/iscsi-onboot.service.
Verifying : isns-utils-libs-0.101-4.el9.x86_64 1/3
Verifying : iscsi-initiator-utils-iscsiuio-6.2.1.9-1.gita65a472.el9.x86_64 2/3
Verifying : iscsi-initiator-utils-6.2.1.9-1.gita65a472.el9.x86_64 3/3
Installed:
iscsi-initiator-utils-6.2.1.9-1.gita65a472.el9.x86_64 iscsi-initiator-utils-iscsiuio-6.2.1.9-1.gita65a472.el9.x86_64 isns-utils-libs-0.101-4.el9.x86_64
Complete!
[aabl@k8smaster1 ~]$ curl -sSfL https://raw.githubusercontent.com/longhorn/longhorn/v1.7.2/scripts/environment_check.sh | bash
[INFO] Required dependencies 'kubectl jq mktemp sort printf' are installed.
[INFO] All nodes have unique hostnames.
[INFO] Waiting for longhorn-environment-check pods to become ready (0/3)...
[INFO] All longhorn-environment-check pods are ready (3/3).
[INFO] MountPropagation is enabled
[INFO] Checking kernel release...
[INFO] Checking iscsid...
[ERROR] Neither iscsid.service nor iscsid.socket is running on k8smaster1.k8s.askov.net
[ERROR] kernel module iscsi_tcp is not enabled on k8snode2.k8s.askov.net
[ERROR] kernel module iscsi_tcp is not enabled on k8snode1.k8s.askov.net
[INFO] Checking multipathd...
[INFO] Checking packages...
[ERROR] nfs-utils is not found in k8snode2.k8s.askov.net.
[ERROR] nfs-utils is not found in k8snode1.k8s.askov.net.
[INFO] Checking nfs client...
[INFO] Cleaning up longhorn-environment-check pods...
[INFO] Cleanup completed.
[aabl@k8smaster1 ~]$
Then the iscsid.service needs to be started
[aabl@k8smaster1 ~]$ sudo systemctl enable iscsid.service --now
Created symlink /etc/systemd/system/multi-user.target.wants/iscsid.service → /usr/lib/systemd/system/iscsid.service.
[aabl@k8smaster1 ~]$
[aabl@k8smaster1 ~]$ sudo modprobe iscsi_tcp
[aabl@k8smaster1 ~]$ curl -sSfL https://raw.githubusercontent.com/longhorn/longhorn/v1.7.2/scripts/environment_check.sh | bash
[INFO] Required dependencies 'kubectl jq mktemp sort printf' are installed.
[INFO] All nodes have unique hostnames.
[INFO] Waiting for longhorn-environment-check pods to become ready (0/3)...
[INFO] All longhorn-environment-check pods are ready (3/3).
[INFO] MountPropagation is enabled
[INFO] Checking kernel release...
[INFO] Checking iscsid...
[ERROR] kernel module iscsi_tcp is not enabled on k8snode2.k8s.askov.net
[ERROR] kernel module iscsi_tcp is not enabled on k8snode1.k8s.askov.net
[INFO] Checking multipathd...
[INFO] Checking packages...
[ERROR] nfs-utils is not found in k8snode2.k8s.askov.net.
[ERROR] nfs-utils is not found in k8snode1.k8s.askov.net.
[INFO] Checking nfs client...
[INFO] Cleaning up longhorn-environment-check pods...
[INFO] Cleanup completed.
[aabl@k8smaster1 ~]$
So this takes care of the kernel module. Let's make the change permanent
[aabl@k8smaster1 ~]$ echo "iscsi_tcp" | sudo tee /etc/modules-load.d/longhorn.conf
iscsi_tcp
[aabl@k8smaster1 ~]$ sudo systemctl restart systemd-modules-load.service
[aabl@k8smaster1 ~]$ sudo systemctl status systemd-modules-load.service
● systemd-modules-load.service - Load Kernel Modules
Loaded: loaded (/usr/lib/systemd/system/systemd-modules-load.service; static)
Active: active (exited) since Sat 2024-11-02 12:51:30 CET; 1s ago
Docs: man:systemd-modules-load.service(8)
man:modules-load.d(5)
Process: 5565 ExecStart=/usr/lib/systemd/systemd-modules-load (code=exited, status=0/SUCCESS)
Main PID: 5565 (code=exited, status=0/SUCCESS)
CPU: 15ms
Nov 02 12:51:30 k8smaster1.k8s.askov.net systemd[1]: Stopped Load Kernel Modules.
Nov 02 12:51:30 k8smaster1.k8s.askov.net systemd[1]: Stopping Load Kernel Modules...
Nov 02 12:51:30 k8smaster1.k8s.askov.net systemd[1]: Starting Load Kernel Modules...
Nov 02 12:51:30 k8smaster1.k8s.askov.net systemd-modules-load[5565]: Inserted module 'iscsi_tcp'
Nov 02 12:51:30 k8smaster1.k8s.askov.net systemd[1]: Finished Load Kernel Modules.
[aabl@k8smaster1 modules-load.d]$
And the last test
[aabl@k8smaster1 ~]$ curl -sSfL https://raw.githubusercontent.com/longhorn/longhorn/v1.7.2/scripts/environment_check.sh | bash
[INFO] Required dependencies 'kubectl jq mktemp sort printf' are installed.
[INFO] All nodes have unique hostnames.
[INFO] Waiting for longhorn-environment-check pods to become ready (0/3)...
[INFO] All longhorn-environment-check pods are ready (3/3).
[INFO] MountPropagation is enabled
[INFO] Checking kernel release...
[INFO] Checking iscsid...
[ERROR] kernel module iscsi_tcp is not enabled on k8snode2.k8s.askov.net
[ERROR] kernel module iscsi_tcp is not enabled on k8snode1.k8s.askov.net
[INFO] Checking multipathd...
[INFO] Checking packages...
[ERROR] nfs-utils is not found in k8snode2.k8s.askov.net.
[ERROR] nfs-utils is not found in k8snode1.k8s.askov.net.
[INFO] Checking nfs client...
[INFO] Cleaning up longhorn-environment-check pods...
[INFO] Cleanup completed.
[aabl@k8smaster1 ~]$
So, to summarize, we need to do these things
sudo dnf install -y nfs-utils iscsi-initiator-utils
sudo systemctl enable iscsid.service --now
echo "iscsi_tcp" | sudo tee /etc/modules-load.d/longhorn.conf
sudo systemctl restart systemd-modules-load.service
And the check is now green
[aabl@k8smaster1 ~]$ curl -sSfL https://raw.githubusercontent.com/longhorn/longhorn/v1.7.2/scripts/environment_check.sh | bash
[INFO] Required dependencies 'kubectl jq mktemp sort printf' are installed.
[INFO] All nodes have unique hostnames.
[INFO] Waiting for longhorn-environment-check pods to become ready (0/3)...
[INFO] All longhorn-environment-check pods are ready (3/3).
[INFO] MountPropagation is enabled
[INFO] Checking kernel release...
[INFO] Checking iscsid...
[INFO] Checking multipathd...
[INFO] Checking packages...
[INFO] Checking nfs client...
[INFO] Cleaning up longhorn-environment-check pods...
[INFO] Cleanup completed.
[aabl@k8smaster1 ~]$
Longhorn does not support sharding, i.e. having one virtual drive span multiple drives. As I have multiple 1TB M.2 drives, I need to combine them to a common file system, if I want to be able to make Volumes bigger than 1TB.
LVM seems like the right choice for this.
The disks we have to work with
[root@k8snode2 ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
nvme4n1 259:0 0 931.5G 0 disk
nvme3n1 259:1 0 931.5G 0 disk
├─nvme3n1p1 259:6 0 600M 0 part /boot/efi
├─nvme3n1p2 259:7 0 1G 0 part /boot
└─nvme3n1p3 259:8 0 929.9G 0 part
└─rl_k8snode2-root 253:0 0 929.9G 0 lvm /
nvme5n1 259:2 0 931.5G 0 disk
nvme1n1 259:3 0 931.5G 0 disk
nvme2n1 259:4 0 931.5G 0 disk
nvme0n1 259:5 0 931.5G 0 disk
[root@k8snode2 ~]#
So let us create the physical volumes
[root@k8snode2 ~]# pvcreate /dev/nvme0n1
Physical volume "/dev/nvme0n1" successfully created.
[root@k8snode2 ~]# pvcreate /dev/nvme1n1
Physical volume "/dev/nvme1n1" successfully created.
[root@k8snode2 ~]# pvcreate /dev/nvme4n1
Physical volume "/dev/nvme4n1" successfully created.
[root@k8snode2 ~]# pvcreate /dev/nvme5n1
Physical volume "/dev/nvme5n1" successfully created.
[root@k8snode2 ~]#
We skip the nvme2n1 disk, as I have other plans for that one.
Then we create the volume group
[root@k8snode2 ~]# vgcreate vg_k8s /dev/nvme0n1 /dev/nvme1n1 /dev/nvme4n1 /dev/nvme5n1
Volume group "vg_k8s" successfully created
[root@k8snode2 ~]#
And then we can create the logical volume
[root@k8snode2 ~]# lvcreate --type raid5 --stripes 3 --extents 100%FREE vg_k8s --name longhorn
Let us see what we have created
[root@k8snode2 ~]# lvdisplay vg_k8s
--- Logical volume ---
LV Path /dev/vg_k8s/longhorn
LV Name longhorn
VG Name vg_k8s
LV UUID Z5KtkL-ak40-8xIz-iZdP-Nsrg-v5Wv-dz30hs
LV Write Access read/write
LV Creation host, time k8snode2.k8s.askov.net, 2024-11-02 14:11:32 +0100
LV Status available
# open 0
LV Size <2.73 TiB
Current LE 715398
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:9
[root@k8snode2 ~]#
And let us then mount it
echo '/dev/vg_k8s/longhorn /longhorn ext4 defaults 0 2' | sudo tee -a /etc/fstab
sudo systemctl daemon-reload
sudo mkdir -p /longhorn
sudo mount -a
https://longhorn.io/docs/1.7.2/deploy/install/install-with-kubectl/
aabl@fedora:~$ kubectl apply -f https://raw.githubusercontent.com/longhorn/longhorn/v1.7.2/deploy/longhorn.yaml
namespace/longhorn-system created
priorityclass.scheduling.k8s.io/longhorn-critical created
serviceaccount/longhorn-service-account created
serviceaccount/longhorn-ui-service-account created
serviceaccount/longhorn-support-bundle created
configmap/longhorn-default-setting created
configmap/longhorn-storageclass created
customresourcedefinition.apiextensions.k8s.io/backingimagedatasources.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/backingimagemanagers.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/backingimages.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/backupbackingimages.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/backups.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/backuptargets.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/backupvolumes.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/engineimages.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/engines.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/instancemanagers.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/nodes.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/orphans.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/recurringjobs.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/replicas.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/settings.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/sharemanagers.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/snapshots.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/supportbundles.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/systembackups.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/systemrestores.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/volumeattachments.longhorn.io created
customresourcedefinition.apiextensions.k8s.io/volumes.longhorn.io created
clusterrole.rbac.authorization.k8s.io/longhorn-role created
clusterrolebinding.rbac.authorization.k8s.io/longhorn-bind created
clusterrolebinding.rbac.authorization.k8s.io/longhorn-support-bundle created
service/longhorn-backend created
service/longhorn-frontend created
service/longhorn-conversion-webhook created
service/longhorn-admission-webhook created
service/longhorn-recovery-backend created
daemonset.apps/longhorn-manager created
deployment.apps/longhorn-driver-deployer created
deployment.apps/longhorn-ui created
aabl@fedora:~$
And we can then check the progress of the install and startup with
When the installation is ready, we can expose the longhorn-ui and check out the system
kubectl expose -n longhorn-system deployment longhorn-ui --port 80 --target-port http --type LoadBalancer
The first thing to do is to ensure that storage is not requested on k8smaster1
And then we must set up the nodes with the correct storage config
I found that the longhorn ui settings do not always translate correctly to the storage class, so we will have to set these by hand
aabl@fedora:~$ kubectl edit -n longhorn-system configmaps longhorn-storageclass
We change the numberOfReplicas to 2 (from 3), as we only have 2 storage nodes.
We also set dataLocality to best-effort
apiVersion: v1
data:
storageclass.yaml: |
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
name: longhorn
annotations:
storageclass.kubernetes.io/is-default-class: "true"
provisioner: driver.longhorn.io
allowVolumeExpansion: true
reclaimPolicy: "Delete"
volumeBindingMode: Immediate
parameters:
numberOfReplicas: "2"
staleReplicaTimeout: "30"
fromBackup: ""
fsType: "ext4"
dataLocality: "best-effort"
unmapMarkSnapChainRemoved: "ignored"
disableRevisionCounter: "true"
dataEngine: "v1"We can create a simple pod with a Persistent Volume Claim with this command
kubectl create -f https://raw.githubusercontent.com/longhorn/longhorn/v1.7.2/examples/pod_with_pvc.yaml
We will see that a Persistent Volume of 2 GB is created and mounted. If we "enter" the pod and create something on the volume, is will remain. Check this by deleting the pod and recreating it.