LinuCエヴァンジェリスト・Open Source Summit Japanボランティアリーダーの鯨井貴博@opensourcetechです。
はじめに
Kubernetes volume機能のhostPathを使ったデータ共有に関するメモです。
やってみる
早速、やってみます。
root@rke2-1:~# cat pod10.yaml
apiVersion: v1
kind: Pod
metadata:
name: testweb
spec:
containers:
- name: testweb
image: nginx
volumeMounts:
- mountPath: /tmp/aaa
name: mydir
- mountPath: /tmp/aaa/1.txt
name: myfile
volumes:
- name: mydir
hostPath:
path: /tmp/aaa
type: DirectoryOrCreate
- name: myfile
hostPath:
path: /tmp/aaa/1.txt
type: FileOrCreate
root@rke2-1:~# kubectl create -f pod10.yaml
pod/testweb created
root@rke2-1:~# kubectl get pod
NAME READY STATUS RESTARTS AGE
testweb 1/1 Running 0 4s
では、実際に/tmp/aaaというディレクトリと1.txtというファイルが出来ているか確認。
root@rke2-1:~# kubectl exec -it testweb -- sh -c /bin/bash root@testweb:/# cd /tmp root@testweb:/tmp# ls aaa root@testweb:/tmp# cd aaa root@testweb:/tmp/aaa# ls 1.txt root@testweb:/tmp/aaa# exit exit
ありますね！
おまけ：hostPathに関する情報
root@rke2-1:~# kubectl explain pods.spec.volumes.hostPath
KIND: Pod
VERSION: v1
FIELD: hostPath <HostPathVolumeSource>
DESCRIPTION:
hostPath represents a pre-existing file or directory on the host machine
that is directly exposed to the container. This is generally used for system
agents or other privileged things that are allowed to see the host machine.
Most containers will NOT need this. More info:
https://kubernetes.io/docs/concepts/storage/volumes#hostpath
Represents a host path mapped into a pod. Host path volumes do not support
ownership management or SELinux relabeling.
FIELDS:
path <string> -required-
path of the directory on the host. If the path is a symlink, it will follow
the link to the real path. More info:
https://kubernetes.io/docs/concepts/storage/volumes#hostpath
type <string>
type for HostPath Volume Defaults to "" More info:
https://kubernetes.io/docs/concepts/storage/volumes#hostpath
Possible enum values:
- `""` For backwards compatible, leave it empty if unset
- `"BlockDevice"` A block device must exist at the given path
- `"CharDevice"` A character device must exist at the given path
- `"Directory"` A directory must exist at the given path
- `"DirectoryOrCreate"` If nothing exists at the given path, an empty
directory will be created there as needed with file mode 0755, having the
same group and ownership with Kubelet.
- `"File"` A file must exist at the given path
- `"FileOrCreate"` If nothing exists at the given path, an empty file will
be created there as needed with file mode 0644, having the same group and
ownership with Kubelet.
- `"Socket"` A UNIX socket must exist at the given path
参照本家サイト
https://kubernetes.io/docs/concepts/storage/volumes/
