初识docker—创建WEB应用容器1python+flask
Docker 客户端
docker 客户端非常简单 ,我们可以直接输入 docker 命令来查看到 Docker 客户端的所有命令选项。
runoob@runoob:~# docker
可以通过命令 docker command --help 更深入的了解指定的 Docker 命令使用方法。
例如我们要查看 docker stats 指令的具体使用方法：
runoob@runoob:~# docker stats --help
运行一个web应用
前面我们运行的容器并没有一些什么特别的用处。
接下来让我们尝试使用 docker 构建一个 web 应用程序。
我们将在docker容器中运行一个 Python Flask 应用来运行一个web应用。
runoob@runoob:~# docker run -d -P training/webapp python app.py
参数说明:
-
-d:让容器在后台运行。
-
-P:将容器内部使用的网络端口映射到我们使用的主机上。
自我练习
[root@CentOS1611 multi-user.target.wants]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
[root@CentOS1611 multi-user.target.wants]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
hello-world latest 05a3bd381fc2 5 weeks ago 1.84kB
[root@CentOS1611 multi-user.target.wants]# docker run -d -P training/webapp python app.py
Unable to find image 'training/webapp:latest' locally
latest: Pulling from training/webapp
e190868d63f8: Pull complete
909cd34c6fd7: Pull complete
0b9bfabab7c1: Pull complete
a3ed95caeb02: Pull complete
10bbbc0fc0ff: Pull complete
fca59b508e9f: Pull complete
e7ae2541b15b: Pull complete
9dd97ef58ce9: Pull complete
a4c1b0cb7af7: Pull complete
Digest: sha256:06e9c1983bd6d5db5fba376ccd63bfa529e8d02f23d5079b8f74a616308fb11d
Status: Downloaded newer image for training/webapp:latest
e318b989ecc3917d14c834c2e80c26046c1c64bd92522b365185652eca265438
[root@CentOS1611 multi-user.target.wants]#
查看 WEB 应用容器
使用 docker ps 来查看我们正在运行的容器
runoob@runoob:~$ docker ps
这里多了端口信息。
PORTS
0.0.0.0:32769->5000/tcp
Docker 开放了 5000 端口（默认 Python Flask 端口）映射到主机端口 32769 上。
这时我们可以通过浏览器访问WEB应用
我们也可以指定 -p 标识来绑定指定端口。
runoob@runoob:~$ docker run -d -p 5000:5000 training/webapp python app.py
docker ps查看正在运行的容器
容器内部的 5000 端口映射到我们本地主机的 5000 端口上。
自我练习
[root@CentOS1611 multi-user.target.wants]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
e318b989ecc3 training/webapp "python app.py" 5 minutes ago Up 5 minutes 0.0.0.0:32768->5000/tcp determined_poitras
[root@CentOS1611 multi-user.target.wants]#
此时我们需要知道这个容器的IP和端口号，从上图可以知道端口号是32768.
想知道网络信息，可以使用Inspect和network ls查看。看是否是与宿主机是一个IP
也可以用命令查看详情
[root@CentOS1611 multi-user.target.wants]# docker inspect e318b989
[
{
"Id": "e318b989ecc3917d14c834c2e80c26046c1c64bd92522b365185652eca265438",
"Created": "2017-10-19T09:37:11.706960417Z",
"Path": "python",
"Args": [
"app.py"
],
"State": {
"Status": "running",
"Running": true,
"Paused": false,
"Restarting": false,
"OOMKilled": false,
"Dead": false,
"Pid": 8408,
"ExitCode": 0,
"Error": "",
"StartedAt": "2017-10-19T09:37:11.923778391Z",
"FinishedAt": "0001-01-01T00:00:00Z"
},
"Image": "sha256:6fae60ef344644649a39240b94d73b8ba9c67f898ede85cf8e947a887b3e6557",
"ResolvConfPath": "/var/lib/docker/containers/e318b989ecc3917d14c834c2e80c26046c1c64bd92522b365185652eca265438/resolv.conf",
"HostnamePath": "/var/lib/docker/containers/e318b989ecc3917d14c834c2e80c26046c1c64bd92522b365185652eca265438/hostname",
"HostsPath": "/var/lib/docker/containers/e318b989ecc3917d14c834c2e80c26046c1c64bd92522b365185652eca265438/hosts",
"LogPath": "/var/lib/docker/containers/e318b989ecc3917d14c834c2e80c26046c1c64bd92522b365185652eca265438/e318b989ecc3917d14c834c2e80c26046c1c64bd92522b365185652eca265438-json.log",
"Name": "/determined_poitras",
"RestartCount": 0,
"Driver": "overlay",
"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,
"CapAdd": null,
"CapDrop": null,
"Dns": [],
"DnsOptions": [],
"DnsSearch": [],
"ExtraHosts": null,
"GroupAdd": null,
"IpcMode": "",
"Cgroup": "",
"Links": null,
"OomScoreAdj": 0,
"PidMode": "",
"Privileged": false,
"PublishAllPorts": true,
"ReadonlyRootfs": false,
"SecurityOpt": null,
"UTSMode": "",
"UsernsMode": "",
"ShmSize": 67108864,
"Runtime": "runc",
"ConsoleSize": [
0,
0
],
"Isolation": "",
"CpuShares": 0,
"Memory": 0,
"NanoCpus": 0,
"CgroupParent": "",
"BlkioWeight": 0,
"BlkioWeightDevice": null,
"BlkioDeviceReadBps": null,
"BlkioDeviceWriteBps": null,
"BlkioDeviceReadIOps": null,
"BlkioDeviceWriteIOps": null,
"CpuPeriod": 0,
"CpuQuota": 0,
"CpuRealtimePeriod": 0,
"CpuRealtimeRuntime": 0,
"CpusetCpus": "",
"CpusetMems": "",
"Devices": [],
"DeviceCgroupRules": null,
"DiskQuota": 0,
"KernelMemory": 0,
"MemoryReservation": 0,
"MemorySwap": 0,
"MemorySwappiness": -1,
"OomKillDisable": false,
"PidsLimit": 0,
"Ulimits": null,
"CpuCount": 0,
"CpuPercent": 0,
"IOMaximumIOps": 0,
"IOMaximumBandwidth": 0
},
"GraphDriver": {
"Data": {
"LowerDir": "/var/lib/docker/overlay/486c8e9e565be0450b7af95e3ee4e64f3175864e812b3963bd82d0674362e72d/root",
"MergedDir": "/var/lib/docker/overlay/eb9d82883cf23ee5f87943ff645256abb0f69f6333a6e07ae3f2d1bc20f19c36/merged",
"UpperDir": "/var/lib/docker/overlay/eb9d82883cf23ee5f87943ff645256abb0f69f6333a6e07ae3f2d1bc20f19c36/upper",
"WorkDir": "/var/lib/docker/overlay/eb9d82883cf23ee5f87943ff645256abb0f69f6333a6e07ae3f2d1bc20f19c36/work"
},
"Name": "overlay"
},
"Mounts": [],
"Config": {
"Hostname": "e318b989ecc3",
"Domainname": "",
"User": "",
"AttachStdin": false,
"AttachStdout": false,
"AttachStderr": false,
"ExposedPorts": {
"5000/tcp": {}
},
"Tty": false,
"OpenStdin": false,
"StdinOnce": false,
"Env": [
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
],
"Cmd": [
"python",
"app.py"
],
"Image": "training/webapp",
"Volumes": null,
"WorkingDir": "/opt/webapp",
"Entrypoint": null,
"OnBuild": null,
"Labels": {}
},
"NetworkSettings": {
"Bridge": "",
"SandboxID": "d11c77eff37a27d80323d2c95b2c59b2a4a472d3ae908095302dc8c1e2478c4f",
"HairpinMode": false,
"LinkLocalIPv6Address": "",
"LinkLocalIPv6PrefixLen": 0,
"Ports": {
"5000/tcp": [
{
"HostIp": "0.0.0.0",
"HostPort": "32768"
}
]
},
"SandboxKey": "/var/run/docker/netns/d11c77eff37a",
"SecondaryIPAddresses": null,
"SecondaryIPv6Addresses": null,
"EndpointID": "46c8c004298140857b84a51b0a3aa146030e176132aa40ea2c71c6c05fe1edcb",
"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": "b9e1d951899da3c16ba5dc6686b54e85c9c49842c3c23d5e3573c1f196b625a7",
"EndpointID": "46c8c004298140857b84a51b0a3aa146030e176132aa40ea2c71c6c05fe1edcb",
"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
}
}
}
}
]
[root@CentOS1611 multi-user.target.wants]#
[root@CentOS1611 multi-user.target.wants]# docker network ls
NETWORK ID NAME DRIVER SCOPE
b9e1d951899d bridge bridge local
7577a140f2d2 host host local
d4edaa484e93 none null local
由此可以采用桥连接，与宿主机是一个IP，连接验证如下
网络端口的快捷方式
通过docker ps 命令可以查看到容器的端口映射，docker还提供了另一个快捷方式：docker port,使用 docker port 可以查看指定 （ID或者名字）容器的某个确定端口映射到宿主机的端口号。
上面我们创建的web应用容器ID为:7a38a1ad55c6 名字为：determined_swanson
我可以使用docker port 7a38a1ad55c6 或docker port determined_swanson来查看容器端口的映射情况
runoob@runoob:~$ docker port 7a38a1ad55c6
5000/tcp -> 0.0.0.0:5000
runoob@runoob:~$ docker port determined_swanson
5000/tcp -> 0.0.0.0:5000
查看WEB应用程序日志
docker logs [ID或者名字] 可以查看容器内部的标准输出。
runoob@runoob:~$ docker logs -f 7a38a1ad55c6
* Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)
192.168.239.1 - - [09/May/2016 16:30:37] "GET / HTTP/1.1" 200 -
192.168.239.1 - - [09/May/2016 16:30:37] "GET /favicon.ico HTTP/1.1" 404 -
-f:表示实时输出。让 dokcer logs 像使用 tail -f 一样来输出容器内部的标准输出。（补充：tail –f的意思是什么？tail 命令从指定点开始将文件写到标准输出.使用tail命令的-f选项可以方便的查阅正在改变的日志文件,tail -f filename会把filename里最尾部的内容显示在屏幕上,并且不但刷新,使你看到最新的文件内容. 用于显示指定文件末尾内容，不指定文件时，作为输入信息进行处理。常用查看日志文件。）
从上面，我们可以看到应用程序使用的是 5000 端口并且能够查看到应用程序的访问日志。
自我练习
宿主机是10.24.11.52，
查看WEB应用程序日志，下面显示的10.24.12.109是刚才访问过这个应用程序的IP地址。
[root@CentOS1611 /]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
e318b989ecc3 training/webapp "python app.py" 23 minutes ago Up 23 minutes 0.0.0.0:32768->5000/tcp determined_poitras
[root@CentOS1611 /]# docker logs -f e318b989ecc3
* Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)
10.24.12.109 - - [19/Oct/2017 09:56:37] "GET / HTTP/1.1" 200 -
10.24.12.109 - - [19/Oct/2017 09:56:37] "GET /favicon.ico HTTP/1.1" 404 -
10.24.12.109 - - [19/Oct/2017 09:57:14] "GET / HTTP/1.1" 200 -
10.24.12.109 - - [19/Oct/2017 09:57:15] "GET /favicon.ico HTTP/1.1" 404 -
[root@CentOS1611 /]#
查看WEB应用程序容器的进程
我们还可以使用 docker top 来查看容器内部运行的进程
runoob@runoob:~$ docker top determined_swanson
检查WEB应用程序
使用 docker inspect 来查看Docker的底层信息。它会返回一个 JSON 文件记录着 Docker 容器的配置和状态信息。
runoob@runoob:~$ docker inspect determined_swanson
[
{
"Id": "7a38a1ad55c6914b360b565819604733db751d86afd2575236a70a2519527361",
"Created": "2016-05-09T16:20:45.427996598Z",
"Path": "python",
"Args": [
"app.py"
],
"State": {
"Status": "running",
......
停止WEB应用容器
runoob@runoob:~$ docker stop determined_swanson
determined_swanson
重启WEB应用容器
已经停止的容器，我们可以使用命令 docker start 来启动。
runoob@runoob:~$ docker start determined_swanson
determined_swanson
docker ps -l 查询最后一次创建的容器：
正在运行的容器，我们可以使用 docker restart 命令来重启
移除WEB应用容器
我们可以使用 docker rm 命令来删除不需要的容器
runoob@runoob:~$ docker rm determined_swanson
determined_swanson
删除容器时，容器必须是停止状态，否则会报如下错误
runoob@runoob:~$ docker rm determined_swanson
Error response from daemon: You cannot remove a running container 7a38a1ad55c6914b360b565819604733db751d86afd2575236a70a2519527361. Stop the container before attempting removal or use -f
