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CentOS环境安装Docker

在CentOS7.6环境下通过yum安装Docker

通过二进制方式安装请参考 在CentOS上以二进制方式安装Docker

下载repo

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cd /etc/yum.repos.d/
wget http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

安装docker

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yum install -y docker-ce

启动docker

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systemctl start docker

systemd下的docker服务

安装并启动docker后,我们可以看到有两个service unit被生成了。

docker.service服务

/usr/lib/systemd/system/docker.service

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[Unit]
Description=Docker Application Container Engine
Documentation=https://docs.docker.com
BindsTo=containerd.service
After=network-online.target firewalld.service containerd.service
Wants=network-online.target
Requires=docker.socket

[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 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

[Install]
WantedBy=multi-user.target

docker.socket服务

/usr/lib/systemd/system/docker.socket

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[Unit]
Description=Docker Socket for the API
PartOf=docker.service

[Socket]
ListenStream=/var/run/docker.sock
SocketMode=0660
SocketUser=root
SocketGroup=docker

[Install]
WantedBy=sockets.target

启动docker的进程

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root       1660      1  0 23:02 ?        00:00:03 /usr/bin/containerd
root 1820 1 0 23:13 ? 00:00:00 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock