Kubernetes 使用容器操作系统（COS）在Google容器引擎中装载NFS卷

在为GKE集群的节点将映像类型从容器vm迁移到cos之后，似乎不再可能为pod装载NFS卷

问题似乎是缺少NFS客户端库，因为命令行中的mount命令在我尝试的所有COS版本（COS-stable-58-9334-62-0、COS-beta-59-9460-20-0、COS-dev-60-9540-0-0）上都失败

失败于

mount: wrong fs type, bad option, bad superblock on mynfsserver:/myshare,
       missing codepage or helper program, or other error
       (for several filesystems (e.g. nfs, cifs) you might
       need a /sbin/mount.<type> helper program)

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Martin，您是手动设置挂载（自己执行挂载），还是让kubernetes通过引用NFS卷的pod代表您执行挂载

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前者行不通。后者会。正如您发现的那样，COS并不随NFS客户端库一起提供，因此GKE通过使用所需的二进制文件设置一个chroot（at/home/kubernetes/containerized_mounter/rootfs）并在其中调用mount来解决这个问题。

我从kubernetes项目中获得了上面提到的解决方案@saad ali，以实现这一点

具体来说，我在云配置中添加了以下内容：

# This script creates a chroot environment containing the tools needed to mount an nfs drive
- path: /tmp/mount_config.sh
  permissions: 0755
  owner: root
  content: |
    #!/bin/sh
    set +x # For debugging

    export USER=root
    export HOME=/home/dockerrunner
    mkdir -p /tmp/mount_chroot
    chmod a+x /tmp/mount_chroot
    cd /tmp/
    echo "Sleeping for 30 seconds because toolbox pull fails otherwise"
    sleep 30
    toolbox --bind /tmp /google-cloud-sdk/bin/gsutil cp gs://<uploaded-file-bucket>/mounter.tar /tmp/mounter.tar
    tar xf /tmp/mounter.tar -C /tmp/mount_chroot/
    mount --bind /tmp/mount_chroot /tmp/mount_chroot
    mount -o remount, exec /tmp/mount_chroot
    mount --rbind /proc /tmp/mount_chroot/proc
    mount --rbind /dev /tmp/mount_chroot/dev
    mount --rbind /tmp /tmp/mount_chroot/tmp
    mount --rbind /mnt /tmp/mount_chroot/mnt

---

这很有效。难看极了，但现在只能这样了。

Saad，感谢您解释了安装pod NFS卷的机制。“cos”上似乎存在DNS问题。如果我在定义持久卷时使用NFS服务器的IP地址，它会在上工作。我也有同样的问题，使用直接IP定义卷会工作，但使用DNS名称不会（尝试过的主机名、内部DNS名称以及公共DNS）。

MountVolume.SetUp failed for volume "kubernetes.io/nfs/b6e6cf44-41e7-11e7-8b00-42010a840079-nfs-mandant1" (spec.Name: "nfs-mandant1") pod "b6e6cf44-41e7-11e7-8b00-42010a840079" (UID: "b6e6cf44-41e7-11e7-8b00-42010a840079") with: mount failed: exit status 1
Mounting command: /home/kubernetes/containerized_mounter/mounter
Mounting arguments: singlefs-1-vm:/data/mandant1 /var/lib/kubelet/pods/b6e6cf44-41e7-11e7-8b00-42010a840079/volumes/kubernetes.io~nfs/nfs-mandant1 nfs []
Output: Mount failed: Mount failed: exit status 32
Mounting command: chroot
Mounting arguments: [/home/kubernetes/containerized_mounter/rootfs mount -t nfs singlefs-1-vm:/data/mandant1 /var/lib/kubelet/pods/b6e6cf44-41e7-11e7-8b00-42010a840079/volumes/kubernetes.io~nfs/nfs-mandant1]
Output: mount.nfs: Failed to resolve server singlefs-1-vm: Temporary failure in name resolution

# This script creates a chroot environment containing the tools needed to mount an nfs drive
- path: /tmp/mount_config.sh
  permissions: 0755
  owner: root
  content: |
    #!/bin/sh
    set +x # For debugging

    export USER=root
    export HOME=/home/dockerrunner
    mkdir -p /tmp/mount_chroot
    chmod a+x /tmp/mount_chroot
    cd /tmp/
    echo "Sleeping for 30 seconds because toolbox pull fails otherwise"
    sleep 30
    toolbox --bind /tmp /google-cloud-sdk/bin/gsutil cp gs://<uploaded-file-bucket>/mounter.tar /tmp/mounter.tar
    tar xf /tmp/mounter.tar -C /tmp/mount_chroot/
    mount --bind /tmp/mount_chroot /tmp/mount_chroot
    mount -o remount, exec /tmp/mount_chroot
    mount --rbind /proc /tmp/mount_chroot/proc
    mount --rbind /dev /tmp/mount_chroot/dev
    mount --rbind /tmp /tmp/mount_chroot/tmp
    mount --rbind /mnt /tmp/mount_chroot/mnt

runcmd:
- /tmp/mount_config.sh
- mkdir -p /mnt/disks/nfs_mount
- chroot /tmp/mount_chroot /bin/mount -t nfs -o rw nfsserver:/sftp /mnt/disks/nfs_mount