Docker的C/S模式详解

Docker的C/S模式

Docker Client通过Remote API与Docker Server通信：

RESTful风格API
STDIN、STDOUT、STDERR

Docker官方的Remote API Reference：

https://docs.docker.com/reference/api/docker_remote_api/

连接方式：

unix:///var/run/docker.sock
tcp://host:port
fd://socketfd

Socket连接方式也就是说，可以通过本地，也可以是远程连接Docker的Server

用grep过滤关键字，第一条中就是正在运行的docker的守护进程

1.[KANO@kelvin ~]$ ps -ef|grep docker
2.root     15518 15039  0 15:41 pts/2    00:00:00 sudo docker -d -H unix:///var/run/docker.sock
3.root     15605 15518  0 15:41 pts/2    00:00:00 docker -d -H unix:///var/run/docker.sock

我们在命令行中使用docker命令就是在使用docker的客户端程序，再于守护进程进行交互

1.[KANO@kelvin ~]$ docker version
2.Client:
3. Version:      1.8.2-fc22
4. API version:  1.20
5. Package Version: docker-1.8.2-7.gitcb216be.fc22.x86_64
6. Go version:   go1.5.1
7. Git commit:   cb216be/1.8.2
8. Built:        
9. OS/Arch:      linux/amd64
10.
11.Server:
12. Version:      1.8.2-fc22
13. API version:  1.20
14. Package Version: 
15. Go version:   go1.5.1
16. Git commit:   cb216be/1.8.2
17. Built:        
18. OS/Arch:      linux/amd64
19.

下面是docker的Remote API，使用linux中nc -U实现socket连接，GET用来查看Remote API中的一个接口info，这个接口用来返回docker的相关信息，指定使用协议是HTTP/1.1

1.[KANO@kelvin ~]$ nc -U /var/run/docker.sock
2.GET /info HTTP/1.1
3.
4.HTTP/1.1 200 OK
5.Content-Type: application/json
6.Server: Docker/1.8.2-fc22 (linux)
7.Date: Tue, 22 Dec 2015 07:44:10 GMT
8.Content-Length: 1667
9.
10.{"ID":"WRM4:ADRR:GPWT:5UBM:QC6S:WEIH:WI5O:ELJ6:6VOI:TFQJ:KKVA:EFW4","Containers":9,"Images":36,"Driver":"devicemapper","DriverStatus":[["Pool Name","docker-253:2-1976018-pool"],["Pool Blocksize","65.54 kB"],["Backing Filesystem","extfs"],["Data file","/dev/loop0"],["Metadata file","/dev/loop1"],["Data Space Used","5.797 GB"],["Data Space Total","107.4 GB"],["Data Space Available","30.75 GB"],["Metadata Space Used","5.951 MB"],["Metadata Space Total","2.147 GB"],["Metadata Space Available","2.142 GB"],["Udev Sync Supported","true"],["Deferred Removal Enabled","false"],["Data loop file","/var/lib/docker/devicemapper/devicemapper/data"],["Metadata loop file","/var/lib/docker/devicemapper/devicemapper/metadata"],["Library Version","1.02.93 (2015-01-30)"]],"MemoryLimit":true,"SwapLimit":true,"CpuCfsPeriod":true,"CpuCfsQuota":true,"IPv4Forwarding":true,"BridgeNfIptables":true,"BridgeNfIp6tables":true,"Debug":false,"NFd":14,"OomKillDisable":true,"NGoroutines":27,"SystemTime":"2015-12-22T15:44:10.848855136+08:00","ExecutionDriver":"native-0.2","LoggingDriver":"json-file","NEventsListener":0,"KernelVersion":"4.2.7-200.fc22.x86_64","OperatingSystem":"Fedora 22 (Twenty Two)","IndexServerAddress":"https://index.docker.io/v1/","RegistryConfig":{"InsecureRegistryCIDRs":["127.0.0.0/8"],"IndexConfigs":{"docker.io":{"Name":"docker.io","Mirrors":null,"Secure":true,"Official":true}},"Mirrors":null},"InitSha1":"c735abe32c7f611ab0c126e178faa4e00a6c23b2","InitPath":"/usr/libexec/docker/dockerinit","NCPU":4,"MemTotal":4038705152,"DockerRootDir":"/var/lib/docker","HttpProxy":"","HttpsProxy":"","NoProxy":"","Name":"kelvin","Labels":null,"ExperimentalBuild":false}
11.

(以上演示的是本地连接)

Docker守护进程的配置和操作

查看守护进程

ps -ef | grep docker
sudo status docker

使用service命令管理守护进程

sudo service docker start
sudo service docker stop
sudo service docker restart

Docker的启动选项

Docker Command Line Reference：

https://docs.docker.com/reference/commandline/cli
启动配置文件

/etc/default/docker
docker -d [OPTIONS]：-d表示以守护进程形式运行
[OPTIONS]是守护进程的配置选项：
运行相关：
- -D,--debug=false
- -e,--exec-driver="native"
- -g,--graph="/var/lib/docker"
- --icc=true
- -l,--log-level="info"
- --label=[]
- -p,--pidfile="/var/run/docker.pid"

Docker服务器连接相关：

-G,--group="docker"
-H,--host=[]
--tls=false
--tlscacert="/home/sven/.docker/ca.pem"
--tlscert="/home/sven/.docker/cert.pem"
--tlskey="/home/sven/.docker/key.pem"
--tlsverify=false

RemoteAPI相关：

--api-enable-cors=false

存储相关：

-S,--storage-driver=""
--selinux-enabled=false
--storage-opt=[]

Registry相关：

--insecure-registry=[]
--registry-mirror=[]

网络设置相关：

-b,--bridge=""
--bip=""
--fixed-cidr=""
--fixed-cidr-v6=""
--dns=[]
--dns-search=[]
--ip=0.0.0.0
--ip-forward=true
--ip-masq=true
--iptables=true
--ipv6=false
--mtu=0

Docker的远程访问

服务端配置：

环境：

第二台安装了Docker的服务器
修改Docker守护进程启动选项，区别服务器
保证Client API与Server API版本一致

对/etc/default/docker添加

DOCKER_OPTS="--label name=docker_server_1 -H tcp://0.0.0.0:2375"

不同服务器name的值不同，用以区别服务器。docker服务一般使用2375端口

都修改完之后重启服务sudo service docker restart

可以使用ifconfig来查看ip，然后使用curl http://ip:2375/info来访问RemoteAPI

客户端配置同服务端：

使用docker -H tcp://ip:2375 info来访问RemoteAPI
使用环境变量

1.export DOCKER_HOST="tcp://ip:2375"
2.docker info