kubernetes - 在 Kubernetes (GKE) 中的一个节点上组合多个本地 SSD

Question

我的容器所需的数据太大，无法放在一个本地 SSD 上。我还需要从我的容器中访问 SSD 作为一个文件系统。所以我需要附加多个。我如何组合它们(单个分区、RAID0 等)并使它们作为容器中的一个卷安装可访问？

此链接分享如何安装 SSD https://cloud.google.com/kubernetes-engine/docs/how-to/persistent-volumes/local-ssd到挂载路径。我不确定您将如何合并多个。

编辑

问题是如何在 GKE 的单个节点上“组合”多个单独安装的 SSD 设备。

Answer 1

WARNING this is experimental and not intended for production use without knowing what you are doing and only tested on gke version 1.16.x.

该方法包括一个使用 configmap 的 daemonset 来使用 nsenter(带有等待技巧)主机命名空间和特权访问，因此您可以管理设备。特别是对于 GKE Local SSD，我们可以卸载这些设备，然后对它们进行 raid0。 InitContainer 用于肮脏的工作，因为这种类型的任务似乎最明显的是你需要标记完成的东西，然后终止特权容器访问(甚至 Pod)。这是它是如何完成的。

该示例假设有 16 个 SSD，但是，您需要根据需要调整硬编码值。另外，确保您的操作系统镜像要求，我使用 Ubuntu。还要确保您使用的 GKE 版本在 sd[b] 启动 local-ssd

配置图

apiVersion: v1
kind: ConfigMap
metadata:
  name: local-ssds-setup
  namespace: search
data:
    setup.sh: |
        #!/bin/bash
        # returns exit codes: 0 = found, 1 = not found
        isMounted() { findmnt -rno SOURCE,TARGET "$1" >/dev/null;} #path or device

        # existing disks & mounts
        SSDS=(/dev/sdb /dev/sdc /dev/sdd /dev/sde /dev/sdf /dev/sdg /dev/sdh /dev/sdi /dev/sdj /dev/sdk /dev/sdl /dev/sdm /dev/sdn /dev/sdo /dev/sdp /dev/sdq)

        # install mdadm utility
        apt-get -y update && apt-get -y install mdadm --no-install-recommends
        apt-get autoremove

        # OPTIONAL: determine what to do with existing, I wipe it here
        if [ -b "/dev/md0" ]
            then
            echo "raid array already created"

            if isMounted "/dev/md0"; then
                echo "already mounted - unmounting"
                umount /dev/md0 &> /dev/null || echo "soft error - assumed device was mounted"
            fi

            mdadm --stop /dev/md0
            mdadm --zero-superblock "${SSDS[@]}"                
        fi

        # unmount disks from host filesystem
        for i in {0..15}
        do 
            umount "${SSDS[i]}" &> /dev/null || echo "${SSDS[i]} already unmounted"
        done

        if isMounted "/dev/sdb";
            then 
            echo ""
            echo "unmount failure - prevent raid0" 1>&2
            exit 1
        fi

        # raid0 array
        yes | mdadm --create /dev/md0 --force --level=0 --raid-devices=16 "${SSDS[@]}"

        echo "raid array created"

        # format 
        mkfs.ext4 -F /dev/md0

        # mount, change /mnt/ssd-array to whatever
        mkdir -p /mnt/ssd-array
        mount /dev/md0 /mnt/ssd-array
        chmod a+w /mnt/ssd-array

    wait.sh: |
        #!/bin/bash
        while sudo fuser /var/{lib/{dpkg,apt/lists},cache/apt/archives}/lock >/dev/null 2>&1; do sleep 1; done

DeamonSet pod 规范

spec:
      hostPID: true
      nodeSelector:
        cloud.google.com/gke-local-ssd: "true"
      volumes:
      - name: setup-script
        configMap:
          name: local-ssds-setup
      - name: host-mount
        hostPath:
          path: /tmp/setup
      initContainers:
      - name: local-ssds-init
        image: marketplace.gcr.io/google/ubuntu1804
        securityContext:
          privileged: true
        volumeMounts:
        - name: setup-script
          mountPath: /tmp
        - name: host-mount
          mountPath: /host
        command:
          - /bin/bash
          - -c
          - |
            set -e
            set -x

            # Copy setup script to the host
            cp /tmp/setup.sh /host

            # Copy wait script to the host 
            cp /tmp/wait.sh /host

            # Wait for updates to complete
            /usr/bin/nsenter -m/proc/1/ns/mnt -- chmod u+x /tmp/setup/wait.sh

            # Give execute priv to script
            /usr/bin/nsenter -m/proc/1/ns/mnt -- chmod u+x /tmp/setup/setup.sh

            # Wait for Node updates to complete
            /usr/bin/nsenter -m/proc/1/ns/mnt /tmp/setup/wait.sh

            # If the /tmp folder is mounted on the host then it can run the script
            /usr/bin/nsenter -m/proc/1/ns/mnt /tmp/setup/setup.sh
      containers:
      - image: "gcr.io/google-containers/pause:2.0"
        name: pause