postgres on k8s with glusterfs as storage - postgresql

Question

I deploy a postgres database on k8s and glusterfs as volume.But every time I restart my pod all of data losses.Why is that?
apiVersion: apps/v1
kind: Deployment
metadata:
name: postgres-deployment
namespace: gitlab
labels:
app: postgres
spec:
replicas: 1
selector:
matchLabels:
app: postgres
template:
metadata:
labels:
app: postgres
spec:
containers:
- name: postgres
image: postgres:13.1
ports:
- containerPort: 5432
volumeMounts:
- mountPath: /var/lib/postgresql
name: postgres
env:
- name: POSTGRES_USERNAME
valueFrom:
secretKeyRef:
name: gitlab
key: postgres_username
- name: POSTGRES_PASSWORD
valueFrom:
secretKeyRef:
name: gitlab
key: postgres_password
- name: POSTGRES_DB
valueFrom:
secretKeyRef:
name: gitlab
key: postgres_db
volumes:
- name: postgres
glusterfs:
endpoints: glusterfs-cluster
path: gv

Answer 1

Define PVC and PV objects. see below for reference.
---
kind: PersistentVolume
apiVersion: v1
metadata:
name: postgres-pv
labels:
type: local
spec:
storageClassName: manual
capacity:
storage: 10GB
accessModes:
- ReadWriteOnce
hostPath:
path: "/mnt/data"
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
labels:
app: postgres
name: postgres-pv-claim
spec:
storageClassName: manual
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 10GB
Then bind the PVC to the pod as shown below
apiVersion: apps/v1beta1
kind: Deployment
metadata:
name: postgres
spec:
template:
metadata:
labels:
app: postgres
spec:
containers:
- name: postgres
...
volumeMounts:
- mountPath: /var/lib/postgresql/data
name: postgres-pv-claim
volumes:
- name: postgres-pv-claim
persistentVolumeClaim:
claimName: postgres-pv-claim

Answer 2

As per the Kubernetes Documentation https://kubernetes.io/docs/concepts/storage/volumes/#glusterfs, Unlike emptyDir, which is erased when a Pod is removed, the contents of a glusterfs volume are preserved and the volume is merely unmounted. I suggest to raise an issue at link https://github.com/kubernetes/kubernetes/issues/new/choose
If you want to install GitLab with PostgresSQL Backend, it will be easier to use below Helm Charts.
https://docs.gitlab.com/charts/
https://artifacthub.io/packages/helm/bitnami/postgresql
https://artifacthub.io/packages/helm/bitnami/postgresql-ha

Answer 3

You can do this:
1.For stateful set services such as databases, StatefulSet controllers should be used to deploy;
2.The storage data resources should be of a shared type, rather than using local volumes as storage, which may be scheduled to other nodes when creating POD objects;