设置docker-compose等待nfs挂载后再启动
默认情况下docker-compose中的服务和nfs挂载动作的执行是不区分先后顺序的，这会导致开机以后docker服务已经启动但nfs挂载点未就绪，于是在docker应用中就无法正常的看到存储池中的文件了。所以这一步是必不可少的。
1.执行sudo -i进入管理员角色
2.执行systemctl list-units | grep mount寻找与fstab中配置对应的信息
# systemctl list-units | grep mount
proc-sys-fs-binfmt_misc.automount loaded active waiting Arbitrary Executable File Formats File System Automount Point
-.mount loaded active mounted Root Mount
boot.mount loaded active mounted /boot
dev-hugepages.mount loaded active mounted Huge Pages File System
dev-mqueue.mount loaded active mounted POSIX Message Queue File System
opt-aquar-storages-aquarpool.mount loaded active mounted /opt/aquar/storages/aquarpool
run-docker-netns-2b854d157421.mount loaded active mounted /run/docker/netns/2b854d157421
run-docker-netns-3485b90319b6.mount loaded active mounted /run/docker/netns/3485b90319b6
run-docker-netns-3502525b2e5c.mount loaded active mounted /run/docker/netns/3502525b2e5c
run-docker-netns-64d92d4b4f3a.mount loaded active mounted /run/docker/netns/64d92d4b4f3a
run-docker-netns-70efe6d06b39.mount loaded active mounted /run/docker/netns/70efe6d06b39
run-docker-netns-7af927c29aa1.mount loaded active mounted /run/docker/netns/7af927c29aa1
run-docker-netns-90d4316ec7d5.mount loaded active mounted /run/docker/netns/90d4316ec7d5
run-docker-netns-a400eb46fb12.mount loaded active mounted /run/docker/netns/a400eb46fb12
run-docker-netns-a9464875f88b.mount loaded active mounted /run/docker/netns/a9464875f88b
run-docker-netns-ba42ec9fab09.mount loaded active mounted /run/docker/netns/ba42ec9fab09
run-docker-netns-ffb36b3ff871.mount loaded active mounted /run/docker/netns/ffb36b3ff871
run-rpc_pipefs.mount loaded active mounted RPC Pipe File System
run-snapd-ns-lxd.mnt.mount loaded active mounted /run/snapd/ns/lxd.mnt
run-snapd-ns.mount loaded active mounted /run/snapd/ns
run-user-1000.mount loaded active mounted /run/user/1000
snap-core18-1944.mount loaded active mounted Mount unit for core18, revision 1944
snap-core18-2344.mount loaded active mounted Mount unit for core18, revision 2344
snap-core20-1405.mount loaded active mounted Mount unit for core20, revision 1405
snap-core20-1434.mount loaded active mounted Mount unit for core20, revision 1434
snap-lxd-19188.mount loaded active mounted Mount unit for lxd, revision 19188
snap-lxd-22753.mount loaded active mounted Mount unit for lxd, revision 22753
snap-snapd-15177.mount loaded active mounted Mount unit for snapd, revision 15177
snap-snapd-15534.mount loaded active mounted Mount unit for snapd, revision 15534
sys-fs-fuse-connections.mount loaded active mounted FUSE Control File System
sys-kernel-config.mount loaded active mounted Kernel Configuration File System
sys-kernel-debug.mount loaded active mounted Kernel Debug File System
sys-kernel-tracing.mount loaded active mounted Kernel Trace File System
var-lib-docker-overlay2-17e05645d70836c66b8113a12cfa21f4a49a8e64c04db752432bd42f7d99c8b0-merged.mount loaded active mounted /var/lib/docker/overlay2/17e05645d70836c66b8113a12cfa21f4a49a8e64c04db752432bd42f7d99c8b0/merged
var-lib-docker-overlay2-19d7431c89a850fe44b164934c522e0fbf44802118e16433e69e6eb989997137-merged.mount loaded active mounted /var/lib/docker/overlay2/19d7431c89a850fe44b164934c522e0fbf44802118e16433e69e6eb989997137/merged
var-lib-docker-overlay2-66d4b69b9f5ffe03f85cda088076fb50d6d0cbaf15f6ab3562e8acb9f92feb51-merged.mount loaded active mounted /var/lib/docker/overlay2/66d4b69b9f5ffe03f85cda088076fb50d6d0cbaf15f6ab3562e8acb9f92feb51/merged
var-lib-docker-overlay2-6956bafabe053a50d166a3d8ea1f0619b50e61455914c70758ec9799b5728d76-merged.mount loaded active mounted /var/lib/docker/overlay2/6956bafabe053a50d166a3d8ea1f0619b50e61455914c70758ec9799b5728d76/merged
var-lib-docker-overlay2-7ff4e2b16cceceed20434c32b275233a71692e11798b20b4933205153f5eb612-merged.mount loaded active mounted /var/lib/docker/overlay2/7ff4e2b16cceceed20434c32b275233a71692e11798b20b4933205153f5eb612/merged
var-lib-docker-overlay2-84b3093e8fa38467607c210fd3ad782cbff8fe9f68aac8951313e8521e17bda1-merged.mount loaded active mounted /var/lib/docker/overlay2/84b3093e8fa38467607c210fd3ad782cbff8fe9f68aac8951313e8521e17bda1/merged
var-lib-docker-overlay2-9d503d0b4bfd3ec259c3fe2fdad8738bdcf09277239e9f055075b3da81a85e97-merged.mount loaded active mounted /var/lib/docker/overlay2/9d503d0b4bfd3ec259c3fe2fdad8738bdcf09277239e9f055075b3da81a85e97/merged
var-lib-docker-overlay2-9fc19e0a50f2ba30f21ab9e276b9d8ef2dbbd04c1f6195a71c03f973a003fde4-merged.mount loaded active mounted /var/lib/docker/overlay2/9fc19e0a50f2ba30f21ab9e276b9d8ef2dbbd04c1f6195a71c03f973a003fde4/merged
var-lib-docker-overlay2-ad306957250317836e1fe5e49e96cef7345f01e670ae91fd6b90099399e20f21-merged.mount loaded active mounted /var/lib/docker/overlay2/ad306957250317836e1fe5e49e96cef7345f01e670ae91fd6b90099399e20f21/merged
var-lib-docker-overlay2-d51ca4df7921532e7ac13e88329dac163ef11e330c7981d568a5bd13a1c23d3e-merged.mount loaded active mounted /var/lib/docker/overlay2/d51ca4df7921532e7ac13e88329dac163ef11e330c7981d568a5bd13a1c23d3e/merged
var-lib-docker-overlay2-e904919db59cdfd899ac2a0532ebbd24390dbf2bde6e25c1d07b6f9ba818c864-merged.mount loaded active mounted /var/lib/docker/overlay2/e904919db59cdfd899ac2a0532ebbd24390dbf2bde6e25c1d07b6f9ba818c864/merged
systemd-remount-fs.service loaded active exited Remount Root and Kernel File Systems
从上面的信息中可以找到挂载任务：opt-aquar-storages-aquarpool.mount
3.找到docker启动任务并备份。
cp /lib/systemd/system/docker.service /lib/systemd/system/docker.service.bak
4.编辑docker启动任务，将第二步中找到的挂载任务设置为他的After项目以及Wants项目。
vim /lib/systemd/system/docker.service
编辑后docker.service内容如下：
[Unit]
Description=Docker Application Container Engine
Documentation=https://docs.docker.com
After=network-online.target docker.socket firewalld.service containerd.service opt-aquar-storages-aquarpool.mount
Wants=network-online.target opt-aquar-storages-aquarpool.mount
Requires=docker.socket containerd.service
[Service]
Type=notify
# the default is not to use systemd for cgroups because the delegate issues still
# exists and systemd currently does not support the cgroup feature set required
# for containers run by docker
ExecStart=/usr/bin/dockerd -H tcp://0.0.0.0:2375 -H fd:// --containerd=/run/containerd/containerd.sock
ExecReload=/bin/kill -s HUP $MAINPID
TimeoutSec=0
RestartSec=2
Restart=always
# Note that StartLimit* options were moved from "Service" to "Unit" in systemd 229.
# Both the old, and new location are accepted by systemd 229 and up, so using the old location
# to make them work for either version of systemd.
StartLimitBurst=3
# Note that StartLimitInterval was renamed to StartLimitIntervalSec in systemd 230.
# Both the old, and new name are accepted by systemd 230 and up, so using the old name to make
# this option work for either version of systemd.
StartLimitInterval=60s
# Having non-zero Limit*s causes performance problems due to accounting overhead
# in the kernel. We recommend using cgroups to do container-local accounting.
LimitNOFILE=infinity
LimitNPROC=infinity
LimitCORE=infinity
# Comment TasksMax if your systemd version does not support it.
# Only systemd 226 and above support this option.
TasksMax=infinity
# set delegate yes so that systemd does not reset the cgroups of docker containers
Delegate=yes
# kill only the docker process, not all processes in the cgroup
KillMode=process
OOMScoreAdjust=-500
[Install]
WantedBy=multi-user.target5.执行systemctl daemon-reload重载系统服务。