I have a multi-node (2) Kubernetes cluster running on bare metal. I understand that 1. hostPath is bad for production and 2. hostPath Persistent Volumes are not supported for multi-node setups. Is there a way that I can safely run apps that are backed by a SQLite database? Over NFS the database locks a lot and really hurts the performance of the apps.
I would probably place the SQLite databases for each app on the hostPath volume and everything would run smoothly again. But I was wondering if there are some workarounds to achieve this, even if I have to restrict apps to a specific node.
It seems you should use Local Persistent Volumes GA.
As per documentation:
A local volume represents a mounted local storage device such as a disk, partition or directory.
Compared to hostPath volumes, local volumes can be used in a durable and portable manner without manually scheduling Pods to nodes, as the system is aware of the volume’s node constraints by looking at the node affinity on the PersistentVolume.
However:
At GA, Local Persistent Volumes do not support dynamic volume provisioning.
More information you can find here, and here.
As one example:
apiVersion: v1
kind: PersistentVolume
metadata:
name: example-pv
spec:
capacity:
storage: 100Gi
# volumeMode field requires BlockVolume Alpha feature gate to be enabled.
volumeMode: Filesystem
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Delete
storageClassName: local-storage
local:
path: /mnt/disks/ssd1
nodeAffinity:
required:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/hostname
operator: In
values:
- example-nodeWith Local Persistent Volumes, the Kubernetes scheduler ensures that a pod using a Local Persistent Volume is always scheduled to the same node