考虑k8s下docker下载镜像太慢，修改了daemon.json，按照手册抄，添加

{
	"exec-opts": ["native.cgroupdriver=systemd"],
	"registry-mirrors": ["https://kn0t2bca.mirror.aliyuncs.com"]
}

结果发现k8s起不来了，

– Unit docker.service has begun starting up.
Aug 10 22:02:01 k8s-master dockerd[1831]: unable to configure the Docker daemon with file /etc/docker/daemon.json: the following directives are specified both as a flag and in the configuration file: exec-opts: (from flag: [native.cgroupdriver=systemd], from file: [native.cgroupdriver=systemd])
Aug 10 22:02:01 k8s-master systemd[1]: docker.service: main process exited, code=exited, status=1/FAILURE
Aug 10 22:02:01 k8s-master systemd[1]: Failed to start Docker Application Container Engine.
– Subject: Unit docker.service has failed
– Defined-By: systemd
– Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
–
– Unit docker.service has failed.
–
– The result is failed.
Aug 10 22:02:01 k8s-master systemd[1]: Unit docker.service entered failed state.
Aug 10 22:02:01 k8s-master systemd[1]: docker.service failed.

原因

启动失败原因：直接启动docker会报错，因为docker.service里有一条配置，和刚才添加的"exec-opts"冲突了

# /lib/systemd/system/docker.service

ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock --exec-opt native.cgroupdriver=systemd

解决方案，保留一处正确的即可：

1.1. # docker.service 找到并删除下面这句话，保存退出，即可解决
--exec-opt native.cgroupdriver=cgroupfs \

1.2. # 或者daemon.json

删exec-opt所在行

2. init 6 重启

重启OK