Overview of Storage persistence in K8s Cluster

Storage classification:

Direct connected storage, centralized shared storage, distributed storage

File storage, block storage, object storage

DAS,NAS,SAN

DAS belongs to direct-attached storage, which connects the storage device directly to the motherboard through SCSI interface or fibre Channel, and cannot realize data sharing.

NAS and SAN belong to centralized shared storage

NAS uses NFS and CIFS (formerly known as SMB, Microsoft) protocols

SAN is divided into FC SAN and IP SAN

IP SAN uses iSCSI technology

NFS implements sharing between linux, while smaba realizes file sharing between linux and windows based on CIFS protocol.

Ceph belongs to distributed sharing system.

The persistent storage supported in the k8s cluster mainly includes:

1. Node node storage

It is divided into random volume emptyDir and fixed volume hostPath

2. Centralized storage nfs

3. Distributed storage ceph

4. Special volumes configmap and secret

When creating a pod, the main storage types supported by the field volumes include:

$kubectl explain Pod.spec.volumes

Cephfs

Cinder

ConfigMap

EmptyDir

Glusterfs

HostPath

Iscsi

Nfs

PersistentVolumeClaim

Rbd

Secret

When creating a pod or controller, you can directly use some back-end storage (such as NFS) as its volumes

You can also use pvc as its back-end volumes,pvc and the nfs above is a level relationship.

When using pvc as its back-end volumes, the access order is pvc---pv--- back-end storage

Create a pod that uses a random volume emptyDir

ApiVersion: v1kind: Podmetadata: labels: run: nginx name: podxxspec: volumes:-name: vol1 emptyDir: {} # use node directory And random containers:-image: nginx name: nginx volumeMounts:-mountPath: / xx # directory mounted inside the container name: vol1-image: busybox name: busybox command: ['sh','-c','sleep 5000'] volumeMounts:-mountPath: / yy name: vol1

Create a pod that uses fixed volumes

ApiVersion: v1kind: Podmetadata: labels: run: nginx name: podxxspec: volumes:-name: vol1 hostPath: path: / aa # automatically create containers:-image: nginx name: nginx volumeMounts:-mountPath: / xx name: vol1-image: busybox name: busybox command: ['sh','-c','sleep 5000'] volumeMounts:-mountPath: / yy on the node where pod resides