Docker基础之运行原理
Docker基础之运行原理
docker run的一个执行流程
Docker是一个Client-Server 的结构的系统，Docker的守护进程在主机上，通过Socker从客户端来访问
DockerServer接收到Docker-Client的指令，就会执行这个命令
Docker为什么比Linux快？
1.Docker有着比虚拟机更小的抽象层
2.Docker利用的是宿主机的内核，vm需要的是Guest OS
虚拟机是加载Guest OS，是分钟级别的
新建一个容器的时候，docker不需要像虚拟机一样重新加载一个操作系统内核，避免引导，利用的是宿主机的操作系统，省略了这个复杂的过程，是秒级的
帮助命令
docker vension //显示docker的命令信息
docker info //显示docker的系统信息，包括镜像和容器的数量
docker 命令 – help //万能命令
镜像命令
docker images 查看仓库源
REPOSITORY 镜像的仓库源
TAG 镜像的标签
IMAGE ID 镜像的ID
CREATED 镜像的创建事件
SIZE 镜像的大小
-a，–a 就是列出所有的镜像
-q，–quiet 只显示镜像的id
docker search 搜索镜像
[root@localhost /]# docker search –help
Usage: docker search [OPTIONS] TERM
Search Docker Hub for images
Options:
-f, –filter filter Filter output based on conditions provided
–format string Pretty-print search using a Go template
–limit int Max number of search results
–no-trunc Don’t truncate output
[root@localhost /]# docker search mysql
NAME DESCRIPTION STARS OFFICIAL AUTOMATED
mysql MySQL is a widely used, open-source relation… 14726 [OK]
mariadb MariaDB Server is a high performing open sou… 5619 [OK]
可选项，通过收藏来过滤
–felter=start=3000 搜索出来的镜像就是START大于3000的
[root@localhost /]# docker search mysql –filter=stars=3000
NAME DESCRIPTION STARS OFFICIAL AUTOMATED
mysql MySQL is a widely used, open-source relation… 14726 [OK]
mariadb MariaDB Server is a high performing open sou… 5619 [OK]
docker pull 下载镜像
[root@localhost /]# docker pull –help
Usage: docker pull [OPTIONS] NAME[:TAG|@DIGEST]
Download an image from a registry
Aliases:
docker image pull, docker pull
Options:
-a, –all-tags Download all tagged images in the repository
–disable-content-trust Skip image verification (default true)
–platform string Set platform if server is multi-platform capable
-q, –quiet Suppress verbose output
[root@localhost /]# docker pull mysql 后面可以添加一个tag来指定版本
Using default tag: latest 如果不写版本，后面默认指定的就是最新版
latest: Pulling from library/mysql
72a69066d2fe: Pull complete 分层下载，docker image的核心，联合文件系统
93619dbc5b36: Pull complete
99da31dd6142: Pull complete
626033c43d70: Pull complete
37d5d7efb64e: Pull complete
ac563158d721: Pull complete
d2ba16033dad: Pull complete
688ba7d5c01a: Pull complete
00e060b6d11d: Pull complete
1c04857f594f: Pull complete
4d7cfa90e6ea: Pull complete
e0431212d27d: Pull complete
Digest: sha256:e9027fe4d91c0153429607251656806cc784e914937271037f7738bd5b8e7709 签名
Status: Downloaded newer image for mysql:latest
docker.io/library/mysql:latest 真实地址
这里的docker pull 等价于 docker pull docker.io/library/mysql:latest
如果我们再次安装mysql 5.7版本的话
[root@localhost /]# docker pull mysql:5.7
5.7: Pulling from library/mysql
72a69066d2fe: Already exists
93619dbc5b36: Already exists
99da31dd6142: Already exists
626033c43d70: Already exists
37d5d7efb64e: Already exists
ac563158d721: Already exists
d2ba16033dad: Already exists
0ceb82207cd7: Pull complete
37f2405cae96: Pull complete
e2482e017e53: Pull complete
70deed891d42: Pull complete
Digest: sha256:f2ad209efe9c67104167fc609cca6973c8422939491c9345270175a300419f94
Status: Downloaded newer image for mysql:5.7
docker.io/library/mysql:5.7
因为之前安装最新版本的时候是已经安装了部分了，现在再次安装5.7就不用全部的层都安装了
docker 删除镜像
docker rmi -f 镜像id或名称
[root@localhost /]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
hello-world latest d2c94e258dcb 7 months ago 13.3kB
mysql 5.7 c20987f18b13 2 years ago 448MB
mysql latest 3218b38490ce 2 years ago 516MB
[root@localhost /]# docker rmi -f c20987f18b13
Untagged: mysql:5.7
Untagged: mysql@sha256:f2ad209efe9c67104167fc609cca6973c8422939491c9345270175a300419f94
Deleted: sha256:c20987f18b130f9d144c9828df630417e2a9523148930dc3963e9d0dab302a76
Deleted: sha256:6567396b065ee734fb2dbb80c8923324a778426dfd01969f091f1ab2d52c7989
Deleted: sha256:0910f12649d514b471f1583a16f672ab67e3d29d9833a15dc2df50dd5536e40f
Deleted: sha256:6682af2fb40555c448b84711c7302d0f86fc716bbe9c7dc7dbd739ef9d757150
Deleted: sha256:5c062c3ac20f576d24454e74781511a5f96739f289edaadf2de934d06e910b92
[root@localhost /]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
hello-world latest d2c94e258dcb 7 months ago 13.3kB
mysql latest 3218b38490ce 2 years ago 516MB
删除多个容器
docker rmi -f 容器id 容器 id 容器id
全部删除
docker rmi -f $(docker images -aq) 将docker images -aq作为参数传入
[root@localhost /]# docker rmi -f $(docker images -aq)
Untagged: hello-world:latest
Untagged: hello-world@sha256:ac69084025c660510933cca701f615283cdbb3aa0963188770b54c31c8962493
Deleted: sha256:d2c94e258dcb3c5ac2798d32e1249e42ef01cba4841c2234249495f87264ac5a
Untagged: mysql:latest
Untagged: mysql@sha256:e9027fe4d91c0153429607251656806cc784e914937271037f7738bd5b8e7709
Deleted: sha256:3218b38490cec8d31976a40b92e09d61377359eab878db49f025e5d464367f3b
Deleted: sha256:aa81ca46575069829fe1b3c654d9e8feb43b4373932159fe2cad1ac13524a2f5
Deleted: sha256:0558823b9fbe967ea6d7174999be3cc9250b3423036370dc1a6888168cbd224d
Deleted: sha256:a46013db1d31231a0e1bac7eeda5ad4786dea0b1773927b45f92ea352a6d7ff9
Deleted: sha256:af161a47bb22852e9e3caf39f1dcd590b64bb8fae54315f9c2e7dc35b025e4e3
Deleted: sha256:feff1495e6982a7e91edc59b96ea74fd80e03674d92c7ec8a502b417268822ff
Deleted: sha256:8805862fcb6ef9deb32d4218e9e6377f35fb351a8be7abafdf1da358b2b287ba
Deleted: sha256:872d2f24c4c64a6795e86958fde075a273c35c82815f0a5025cce41edfef50c7
Deleted: sha256:6fdb3143b79e1be7181d32748dd9d4a845056dfe16ee4c827410e0edef5ad3da
Deleted: sha256:b0527c827c82a8f8f37f706fcb86c420819bb7d707a8de7b664b9ca491c96838
Deleted: sha256:75147f61f29796d6528486d8b1f9fb5d122709ea35620f8ffcea0e0ad2ab0cd0
Deleted: sha256:2938c71ddf01643685879bf182b626f0a53b1356138ef73c40496182e84548aa
Deleted: sha256:ad6b69b549193f81b039a1d478bc896f6e460c77c1849a4374ab95f9a3d2cea2
[root@localhost /]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
说明：需要有了镜像才能使用容器，以一个linux容器中的centos镜像为例
docker pull centos
新建容器并启动
docker run [可选参数] image
参数说明
–name=“Name” 容器名字，tomcat01、tomcat02来区分
-d 后台方式运行，
-it 使用交互方式运行，进入容器查看内容
-p 指定容器端口 有四种方式
-p ip:主机端口：容器端口
-p 主机端口:容器端口
-p 容器端口
容器端口
启动并进入容器
[root@localhost /]# docker run -it centos /bin/bash
[root@82893955fb41 /]#
[root@82893955fb41 /]# ls 查看容器内的centos
bin dev etc home lib lib64 lost+found media mnt opt proc root run sbin srv sys tmp usr var
此时容器内部的centos与外部的centos没有关系
退出容器
[root@82893955fb41 /]# exit
exit
[root@localhost /]#
docker ps 命令
列出所有正在运行的容器
-a 列出所有正在运行的容器与曾经运行的容器
-n=个数 显示最近创建的N个容器
-q 只显示容器的编号
列出所有运行中的容器
[root@localhost /]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
列出曾经运行的容器
[root@localhost /]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
82893955fb41 centos “/bin/bash” 3 minutes ago Exited (0) About a minute ago elegant_kirch
0a5890a6d948 d2c94e258dcb “/hello” 9 hours ago Exited (0) 9 hours ago bold_chebyshev
列出最近创建的一个容器
[root@localhost /]# docker ps -n=1
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
82893955fb41 centos “/bin/bash” 6 minutes ago Exited (0) 4 minutes ago elegant_kirch
列出所有容器的编号
[root@localhost /]# docker ps -aq
82893955fb41
0a5890a6d948
exit 容器退出并停止
CTRL+P+Q 容器不停止退出
[root@localhost ~]# docker run -it centos /bin/bash
[root@4bdda8d6242e /]# docker ps
bash: docker: command not found
[root@4bdda8d6242e /]# [root@localhost ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
4bdda8d6242e centos “/bin/bash” 8 minutes ago Up 8 minutes vigorous_gagarin
删除容器
docker rm 移除容器
docjer rmi 移除镜像
docker rm 容器id 删除指定容器，不能删除正在运行的容器，如果需要强制删除，就需要 加入 -f
docker rm -f $(docker ps -aq) 删除全部容器
docker ps -a -q | xargs dockers rm 删除所有容器
启动与停止容器
docker start 容器id 启动容器
docker restart 容器id 重启容器
docker stop 容器id 停止正在运行容器
docker kill 容器id 强制杀死正在运行的容器
先启动容器然后退出容器，再用历史中id启动容器，利用docker stop id 停止容器
[root@localhost ~]# docker run -it centos /bin/bash
[root@a54518f477e9 /]# exit
exit
[root@localhost ~]# docker os
docker: ‘os’ is not a docker command.
See ‘docker –help’
[root@localhost ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
[root@localhost ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
a54518f477e9 centos “/bin/bash” 56 seconds ago Exited (0) 49 seconds ago ecstatic_keller
[root@localhost ~]# docker start a54518f477e9
a54518f477e9
[root@localhost ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
a54518f477e9 centos “/bin/bash” About a minute ago Up 6 seconds ecstatic_keller
[root@localhost ~]# docker stop a54518f477e9
a54518f477e9
[root@localhost ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
其他命令
后台启动容器
通过docker run -a 镜像名 来启动容器
[root@localhost ~]# docker run -d centos
bd19d67283774aede6ea1042ff9e2e14ae41d349285a18cf23faf8a18bf73572
[root@localhost ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
使用后台运行的时候，如果没有前台进程，如-it，docker发送没有前台应用，就会自动停止，也就是说我们就是只启动了一个CentOS，没有没有使用它，然后就自动停止了
查看日志
docker logs -f -t –tail 显示的日志条数 容器名
查看容器中的进程信息
top
[root@localhost ~]# docker run -it centos /bin/bash
[root@f6306cb0eaaa /]# [root@localhost ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
f6306cb0eaaa centos “/bin/bash” 10 seconds ago Up 9 seconds funny_clarke
[root@localhost ~]# docker top f6306cb0eaaa
UID PID PPID C STIME TTY TIME CMD
root 72103 72079 0 05:18 pts/0 00:00:00 /bin/bash
查看镜像的元数据
docker inspect 容器id
[root@localhost ~]# docker inspect f6306cb0eaaa
[
{
“Id”: “f6306cb0eaaa4894af9e6cd5d276c93fcadb3cfe5c1d2c46b44cb91d02d39ece”,
“Created”: “2023-12-23T13:18:36.76455639Z”,
“Path”: “/bin/bash”,
“Args”: [],
“State”: {
“Status”: “running”,
“Running”: true,
“Paused”: false,
“Restarting”: false,
“OOMKilled”: false,
“Dead”: false,
“Pid”: 72103,
“ExitCode”: 0,
“Error”: “”,
“StartedAt”: “2023-12-23T13:18:37.176971566Z”,
“FinishedAt”: “0001-01-01T00:00:00Z”
},
“Image”: “sha256:5d0da3dc976460b72c77d94c8a1ad043720b0416bfc16c52c45d4847e53fadb6”,
“ResolvConfPath”: “/var/lib/docker/containers/f6306cb0eaaa4894af9e6cd5d276c93fcadb3cfe5c1d2c46b44cb91d02d39ece/resolv.conf”,
“HostnamePath”: “/var/lib/docker/containers/f6306cb0eaaa4894af9e6cd5d276c93fcadb3cfe5c1d2c46b44cb91d02d39ece/hostname”,
“HostsPath”: “/var/lib/docker/containers/f6306cb0eaaa4894af9e6cd5d276c93fcadb3cfe5c1d2c46b44cb91d02d39ece/hosts”,
“LogPath”: “/var/lib/docker/containers/f6306cb0eaaa4894af9e6cd5d276c93fcadb3cfe5c1d2c46b44cb91d02d39ece/f6306cb0eaaa4894af9e6cd5d276c93fcadb3cfe5c1d2c46b44cb91d02d39ece-json.log”,
“Name”: “/funny_clarke”,
“RestartCount”: 0,
“Driver”: “overlay2”,
“Platform”: “linux”,
“MountLabel”: “”,
“ProcessLabel”: “”,
“AppArmorProfile”: “”,
“ExecIDs”: null,
“HostConfig”: {
“Binds”: null,
“ContainerIDFile”: “”,
“LogConfig”: {
“Type”: “json-file”,
“Config”: {}
},
“NetworkMode”: “default”,
“PortBindings”: {},
“RestartPolicy”: {
“Name”: “no”,
“MaximumRetryCount”: 0
},
“AutoRemove”: false,
“VolumeDriver”: “”,
“VolumesFrom”: null,
“ConsoleSize”: [
46,
150
],
“CapAdd”: null,
“CapDrop”: null,
“CgroupnsMode”: “host”,
“Dns”: [],
“DnsOptions”: [],
“DnsSearch”: [],
“ExtraHosts”: null,
“GroupAdd”: null,
“IpcMode”: “private”,
“Cgroup”: “”,
“Links”: null,
“OomScoreAdj”: 0,
“PidMode”: “”,
“Privileged”: false,
“PublishAllPorts”: false,
“ReadonlyRootfs”: false,
“SecurityOpt”: null,
“UTSMode”: “”,
“UsernsMode”: “”,
“ShmSize”: 67108864,
“Runtime”: “runc”,
“Isolation”: “”,
“CpuShares”: 0,
“Memory”: 0,
“NanoCpus”: 0,
“CgroupParent”: “”,
“BlkioWeight”: 0,
“BlkioWeightDevice”: [],
“BlkioDeviceReadBps”: [],
“BlkioDeviceWriteBps”: [],
“BlkioDeviceReadIOps”: [],
“BlkioDeviceWriteIOps”: [],
“CpuPeriod”: 0,
“CpuQuota”: 0,
“CpuRealtimePeriod”: 0,
“CpuRealtimeRuntime”: 0,
“CpusetCpus”: “”,
“CpusetMems”: “”,
“Devices”: [],
“DeviceCgroupRules”: null,
“DeviceRequests”: null,
“MemoryReservation”: 0,
“MemorySwap”: 0,
“MemorySwappiness”: null,
“OomKillDisable”: false,
“PidsLimit”: null,
“Ulimits”: null,
“CpuCount”: 0,
“CpuPercent”: 0,
“IOMaximumIOps”: 0,
“IOMaximumBandwidth”: 0,
“MaskedPaths”: [
“/proc/asound”,
“/proc/acpi”,
“/proc/kcore”,
“/proc/keys”,
“/proc/latency_stats”,
“/proc/timer_list”,
“/proc/timer_stats”,
“/proc/sched_debug”,
“/proc/scsi”,
“/sys/firmware”,
“/sys/devices/virtual/powercap”
],
“ReadonlyPaths”: [
“/proc/bus”,
“/proc/fs”,
“/proc/irq”,
“/proc/sys”,
“/proc/sysrq-trigger”
]
},
“GraphDriver”: {
“Data”: {
“LowerDir”: “/var/lib/docker/overlay2/2c81f36d8e5aab055a767c095a3a48923c509524e9382ab25b90f3cbff4d5212-init/diff:/var/lib/docker/overlay2/f59ecbfd0d480206326041d65a34502077c4b4b3d8ea3fe8d3bea282d054df5b/diff”,
“MergedDir”: “/var/lib/docker/overlay2/2c81f36d8e5aab055a767c095a3a48923c509524e9382ab25b90f3cbff4d5212/merged”,
“UpperDir”: “/var/lib/docker/overlay2/2c81f36d8e5aab055a767c095a3a48923c509524e9382ab25b90f3cbff4d5212/diff”,
“WorkDir”: “/var/lib/docker/overlay2/2c81f36d8e5aab055a767c095a3a48923c509524e9382ab25b90f3cbff4d5212/work”
},
“Name”: “overlay2”
},
“Mounts”: [],
“Config”: {
“Hostname”: “f6306cb0eaaa”,
“Domainname”: “”,
“User”: “”,
“AttachStdin”: true,
“AttachStdout”: true,
“AttachStderr”: true,
“Tty”: true,
“OpenStdin”: true,
“StdinOnce”: true,
“Env”: [
“PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin”
],
“Cmd”: [
“/bin/bash”
],
“Image”: “centos”,
“Volumes”: null,
“WorkingDir”: “”,
“Entrypoint”: null,
“OnBuild”: null,
“Labels”: {
“org.label-schema.build-date”: “20210915”,
“org.label-schema.license”: “GPLv2”,
“org.label-schema.name”: “CentOS Base Image”,
“org.label-schema.schema-version”: “1.0”,
“org.label-schema.vendor”: “CentOS”
}
},
“NetworkSettings”: {
“Bridge”: “”,
“SandboxID”: “ce88100eec36b666214ed141c32055f8643ccc59ea3ebc12828d61310acacf06”,
“HairpinMode”: false,
“LinkLocalIPv6Address”: “”,
“LinkLocalIPv6PrefixLen”: 0,
“Ports”: {},
“SandboxKey”: “/var/run/docker/netns/ce88100eec36”,
“SecondaryIPAddresses”: null,
“SecondaryIPv6Addresses”: null,
“EndpointID”: “f35174bff621aaec194c51d0614b915a3608240adde06f82f45e47d5152a6107”,
“Gateway”: “172.17.0.1”,
“GlobalIPv6Address”: “”,
“GlobalIPv6PrefixLen”: 0,
“IPAddress”: “172.17.0.2”,
“IPPrefixLen”: 16,
“IPv6Gateway”: “”,
“MacAddress”: “02:42:ac:11:00:02”,
“Networks”: {
“bridge”: {
“IPAMConfig”: null,
“Links”: null,
“Aliases”: null,
“NetworkID”: “712ef386b938f762e6d3b55ab127383431cf782f3c717aaaa2dcd068b8c0e1ee”,
“EndpointID”: “f35174bff621aaec194c51d0614b915a3608240adde06f82f45e47d5152a6107”,
“Gateway”: “172.17.0.1”,
“IPAddress”: “172.17.0.2”,
“IPPrefixLen”: 16,
“IPv6Gateway”: “”,
“GlobalIPv6Address”: “”,
“GlobalIPv6PrefixLen”: 0,
“MacAddress”: “02:42:ac:11:00:02”,
“DriverOpts”: null
}
}
}
}
]