k8s/StudyNotes/Storage

• Docker storage - Storage drivers[aufs,btrfs,etc.] and volume's [Local,VMware,rexray/ebs]
  • /var/lib/docker/ [aufs, containers, image, volumes]

  • Create persistent storage for docker container

         docker volume create data_vol
         docker run -v data_vol:/var/lib/mysql mysql
         # if no pre-created volume docker creates it on the fly
         
         docker run --mount type=bind,source=/data/mysql,target=/varlib/mysql mysql 
      

  • Bind mount form anywhere, volume mount from /var/lib/docker/volumes/

• k8s - Was just docker, now CRI container runtime interface to support docker,rkt, cri-o

  • Same for network CNI Container network interface

  • Same for storage CSI Container Storage Interface - Amazon EBS, PureStorage

    • CSI spec https://github.com/container-storage-interface

• k8s volume options [hostPath:, nfs, awsElasticBlockStore:, etc]

• k8s centralize storage with PersistentVolume, then pods claim matching pv with VolumeClaims.

• PV(PersistenVolume) on cloud provider still has to manually created.

  • Automate this with Dynamic Provisioning using StorageClass object

  • e.g. SC auto creates PV(PersistVol) and PVC(PVclaim) grabs disk from SC

    apiVersion: storage.k8s.io/v1
    kind: storageClass
    metadata:
      name: google-storage
    provisioner: kubernetes.io/gce-pd
    parameters:
      type: pd-standard
      replication-type: none

    • In the PVC obj we now refer to the storageClassName: google-storage defined in SC