我们的一个虚拟机被重启，现在docker无法启动。当我尝试通过systemctl start docker-standalone启动服务时，我得到：
docker-standalone.service的作业失败，因为控制进程退出并返回错误代码。有关详细信息，请参阅“systemctl status docker-standalone.service”和“journalctl -xe”。
当我检查journalctl -xe时，我看到这样的内容：

Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.689962814-06:00" level=info msg="skip loading plugin \"io.containerd.snapshotter.v1.aufs\"..." error="aufs is not supported (modprobe aufs failed: exit sta Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.689984624-06:00" level=info msg="loading plugin \"io.containerd.snapshotter.v1.devmapper\"..." type=io.containerd.snapshotter.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690001784-06:00" level=warning msg="failed to load plugin io.containerd.snapshotter.v1.devmapper" error="devmapper not configured" Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690010545-06:00" level=info msg="loading plugin \"io.containerd.snapshotter.v1.native\"..." type=io.containerd.snapshotter.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690029639-06:00" level=info msg="loading plugin \"io.containerd.snapshotter.v1.overlayfs\"..." type=io.containerd.snapshotter.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690106664-06:00" level=info msg="loading plugin \"io.containerd.snapshotter.v1.zfs\"..." type=io.containerd.snapshotter.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690248278-06:00" level=info msg="skip loading plugin \"io.containerd.snapshotter.v1.zfs\"..." error="path /var/lib/docker-standalone/containerd/daemon/io.c Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690261292-06:00" level=info msg="loading plugin \"io.containerd.metadata.v1.bolt\"..." type=io.containerd.metadata.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690274990-06:00" level=warning msg="could not use snapshotter devmapper in metadata plugin" error="devmapper not configured" Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690282381-06:00" level=info msg="metadata content store policy set" policy=shared Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690356752-06:00" level=info msg="loading plugin \"io.containerd.differ.v1.walking\"..." type=io.containerd.differ.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690370466-06:00" level=info msg="loading plugin \"io.containerd.gc.v1.scheduler\"..." type=io.containerd.gc.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690399678-06:00" level=info msg="loading plugin \"io.containerd.service.v1.introspection-service\"..." type=io.containerd.service.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690427410-06:00" level=info msg="loading plugin \"io.containerd.service.v1.containers-service\"..." type=io.containerd.service.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690438870-06:00" level=info msg="loading plugin \"io.containerd.service.v1.content-service\"..." type=io.containerd.service.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690449099-06:00" level=info msg="loading plugin \"io.containerd.service.v1.diff-service\"..." type=io.containerd.service.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690462529-06:00" level=info msg="loading plugin \"io.containerd.service.v1.images-service\"..." type=io.containerd.service.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690476538-06:00" level=info msg="loading plugin \"io.containerd.service.v1.leases-service\"..." type=io.containerd.service.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690489694-06:00" level=info msg="loading plugin \"io.containerd.service.v1.namespaces-service\"..." type=io.containerd.service.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690511122-06:00" level=info msg="loading plugin \"io.containerd.service.v1.snapshots-service\"..." type=io.containerd.service.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690524355-06:00" level=info msg="loading plugin \"io.containerd.runtime.v1.linux\"..." type=io.containerd.runtime.v1 Oct 29 13:56:16 server35.mydomain.com dockerd[4382]: Failed to start containerd: timeout waiting for containerd to start Oct 29 13:56:16 server35.mydomain.com systemd[1]: docker-standalone.service: main process exited, code=exited, status=1/FAILURE Oct 29 13:56:16 server35.mydomain.com systemd[1]: Failed to start Docker Application Container Engine Standalone Version.
-- Subject: Unit docker-standalone.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit docker-standalone.service has failed.
--
-- The result is failed. Oct 29 13:56:16 server35.mydomain.com systemd[1]: Unit docker-standalone.service entered failed state. Oct 29 13:56:16 server35.mydomain.com systemd[1]: docker-standalone.service failed. Oct 29 13:56:16 server35.mydomain.com polkitd[800]: Unregistered Authentication Agent for unix-process:4406:22575 (system bus name :1.24, object path /org/freedesktop/PolicyKit1/AuthenticationAgent, locale en_US.UTF-8) (disconnected f Oct 29 13:56:16 server35.mydomain.com systemd[1]: docker-standalone.service holdoff time over, scheduling restart. Oct 29 13:56:16 server35.mydomain.com systemd[1]: Stopped Docker Application Container Engine Standalone Version.
-- Subject: Unit docker-standalone.service has finished shutting down
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit docker-standalone.service has finished shutting down. Oct 29 13:56:16 server35.mydomain.com systemd[1]: start request repeated too quickly for docker-standalone.service Oct 29 13:56:16 server35.mydomain.com systemd[1]: Failed to start Docker Application Container Engine Standalone Version.
-- Subject: Unit docker-standalone.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit docker-standalone.service has failed.
--
-- The result is failed. Oct 29 13:56:16 server35.mydomain.com systemd[1]: Unit docker-standalone.service entered failed state. Oct 29 13:56:16 server35.mydomain.com systemd[1]: docker-standalone.service failed.Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.689962814-06:00" level=info msg="skip loading plugin \"io.containerd.snapshotter.v1.aufs\"..." error="aufs is not supported (modprobe aufs failed: exit sta Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.689984624-06:00" level=info msg="loading plugin \"io.containerd.snapshotter.v1.devmapper\"..." type=io.containerd.snapshotter.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690001784-06:00" level=warning msg="failed to load plugin io.containerd.snapshotter.v1.devmapper" error="devmapper not configured" Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690010545-06:00" level=info msg="loading plugin \"io.containerd.snapshotter.v1.native\"..." type=io.containerd.snapshotter.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690029639-06:00" level=info msg="loading plugin \"io.containerd.snapshotter.v1.overlayfs\"..." type=io.containerd.snapshotter.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690106664-06:00" level=info msg="loading plugin \"io.containerd.snapshotter.v1.zfs\"..." type=io.containerd.snapshotter.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690248278-06:00" level=info msg="skip loading plugin \"io.containerd.snapshotter.v1.zfs\"..." error="path /var/lib/docker-standalone/containerd/daemon/io.c Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690261292-06:00" level=info msg="loading plugin \"io.containerd.metadata.v1.bolt\"..." type=io.containerd.metadata.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690274990-06:00" level=warning msg="could not use snapshotter devmapper in metadata plugin" error="devmapper not configured" Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690282381-06:00" level=info msg="metadata content store policy set" policy=shared Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690356752-06:00" level=info msg="loading plugin \"io.containerd.differ.v1.walking\"..." type=io.containerd.differ.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690370466-06:00" level=info msg="loading plugin \"io.containerd.gc.v1.scheduler\"..." type=io.containerd.gc.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690399678-06:00" level=info msg="loading plugin \"io.containerd.service.v1.introspection-service\"..." type=io.containerd.service.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690427410-06:00" level=info msg="loading plugin \"io.containerd.service.v1.containers-service\"..." type=io.containerd.service.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690438870-06:00" level=info msg="loading plugin \"io.containerd.service.v1.content-service\"..." type=io.containerd.service.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690449099-06:00" level=info msg="loading plugin \"io.containerd.service.v1.diff-service\"..." type=io.containerd.service.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690462529-06:00" level=info msg="loading plugin \"io.containerd.service.v1.images-service\"..." type=io.containerd.service.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690476538-06:00" level=info msg="loading plugin \"io.containerd.service.v1.leases-service\"..." type=io.containerd.service.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690489694-06:00" level=info msg="loading plugin \"io.containerd.service.v1.namespaces-service\"..." type=io.containerd.service.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690511122-06:00" level=info msg="loading plugin \"io.containerd.service.v1.snapshots-service\"..." type=io.containerd.service.v1 Oct 29 13:56:11 server35.mydomain.com dockerd[4382]: time="2021-10-29T13:56:11.690524355-06:00" level=info msg="loading plugin \"io.containerd.runtime.v1.linux\"..." type=io.containerd.runtime.v1 Oct 29 13:56:16 server35.mydomain.com dockerd[4382]: Failed to start containerd: timeout waiting for containerd to start Oct 29 13:56:16 server35.mydomain.com systemd[1]: docker-standalone.service: main process exited, code=exited, status=1/FAILURE Oct 29 13:56:16 server35.mydomain.com systemd[1]: Failed to start Docker Application Container Engine Standalone Version.
-- Subject: Unit docker-standalone.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit docker-standalone.service has failed.
--
-- The result is failed. Oct 29 13:56:16 server35.mydomain.com systemd[1]: Unit docker-standalone.service entered failed state. Oct 29 13:56:16 server35.mydomain.com systemd[1]: docker-standalone.service failed. Oct 29 13:56:16 server35.mydomain.com polkitd[800]: Unregistered Authentication Agent for unix-process:4406:22575 (system bus name :1.24, object path /org/freedesktop/PolicyKit1/AuthenticationAgent, locale en_US.UTF-8) (disconnected f Oct 29 13:56:16 server35.mydomain.com systemd[1]: docker-standalone.service holdoff time over, scheduling restart. Oct 29 13:56:16 server35.mydomain.com systemd[1]: Stopped Docker Application Container Engine Standalone Version.
-- Subject: Unit docker-standalone.service has finished shutting down
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit docker-standalone.service has finished shutting down. Oct 29 13:56:16 server35.mydomain.com systemd[1]: start request repeated too quickly for docker-standalone.service Oct 29 13:56:16 server35.mydomain.com systemd[1]: Failed to start Docker Application Container Engine Standalone Version.
-- Subject: Unit docker-standalone.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit docker-standalone.service has failed.
--
-- The result is failed. Oct 29 13:56:16 server35.mydomain.com systemd[1]: Unit docker-standalone.service entered failed state. Oct 29 13:56:16 server35.mydomain.com systemd[1]: docker-standalone.service failed.

我注意到了这句关键的台词：
Failed to start containerd: timeout waiting for containerd to start个
我们试着重新安装Docker，但没用。
我们的版本有：

$ ds version
Client: Docker Engine - Community
 Version:           20.10.8
 API version:       1.40
 Go version:        go1.16.6
 Git commit:        3967b7d
 Built:             Fri Jul 30 19:55:49 2021
 OS/Arch:           linux/amd64
 Context:           default
 Experimental:      true

Server: Docker Engine - Community
 Engine:
  Version:          19.03.13
  API version:      1.40 (minimum version 1.12)
  Go version:       go1.13.15
  Git commit:       4484c46d9d
  Built:            Wed Sep 16 17:02:21 2020
  OS/Arch:          linux/amd64
  Experimental:     true
 containerd:
  Version:          1.4.9
  GitCommit:        e25210fe30a0a703442421b0f60afac609f950a3
 runc:
  Version:          1.0.1
  GitCommit:        v1.0.1-0-g4144b63
 docker-init:
  Version:          0.18.0
  GitCommit:        fec3683

我们运行的是Centos 7，Linux内核为3.10.0-514.el7.x86_64
我们还尝试根据in this SO post的建议删除/var/run中的docker文件，但这是Ubuntu，涉及到snap，清除/var/run中的docker文件没有帮助。
为了避免混淆服务名称，ds只是一个helper脚本，定义如下：

# !/bin/bash

docker -H unix:///var/run/docker-standalone.sock "$@"

我们怎么让多克重新开始？