Docker的Remote Api并不是1.12才有的，Docker1.12的Remote Api升到了1.24。Remote api的使用在1.12中没有大的变化，稍微大一点的变化是到这个版本之后，二进制文件分裂成了主client的docker以及主server的dockerd了。在centos上通过systemd的配置变化不大，无非是将tcp://ip:port设定到启动的Option中而已，下面来看一下如何设定和简单使用。

事前确认

可以看到只有unix socket的方式

[root@host34 system]# systemctl status docker
● docker.service - Docker Application Container Engine
   Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor preset: disabled)
   Active: active (running) since Sat 2016-08-20 09:17:29 EDT; 5min ago
     Docs: https://docs.docker.com
 Main PID: 12409 (dockerd)
   Memory: 31.5M
   CGroup: /system.slice/docker.service
           tq12409 /usr/bin/dockerd
           mq12412 docker-containerd -l unix:///var/run/docker/libcontainerd/docker-containerd.sock --shim docker-containerd-shim --metrics-inte...

修正设定文件

[root@host34 system]# cp /usr/lib/systemd/system/docker.service /usr/lib/systemd/system/docker.service.bak
[root@host34 system]# vi /usr/lib/systemd/system/docker.service
[root@host34 system]# diff /usr/lib/systemd/system/docker.service /usr/lib/systemd/system/docker.service.bak
11c11
< ExecStart=/usr/bin/dockerd -H 192.168.32.34:2375
---
> ExecStart=/usr/bin/dockerd
[root@host34 system]#

daemon-reload和重启docker

命令：systemctl daemon-reload
命令：systemctl restart docker

[root@host34 system]# systemctl daemon-reload
[root@host34 system]# systemctl restart docker
[root@host34 system]# systemctl status docker
● docker.service - Docker Application Container Engine
   Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor preset: disabled)
   Active: active (running) since Sat 2016-08-20 23:48:09 EDT; 10s ago
     Docs: https://docs.docker.com
 Main PID: 13063 (dockerd)
   Memory: 21.7M
   CGroup: /system.slice/docker.service
           tq13063 /usr/bin/dockerd -H 192.168.32.34:2375
           mq13067 docker-containerd -l unix:///var/run/docker/libcontainerd/docker-containerd.sock --shim docker-containerd-shim --metrics-inte...

确认remote api

使用curl确认remote api版本和docker版本信息

[root@host34 system]# curl http://192.168.32.34:2375/version
{
   "Version":"1.12.1","ApiVersion":"1.24","GitCommit":"23cf638","GoVersion":"go1.6.3","Os":"linux","Arch":"amd64","KernelVersion":"3.10.0-327.28.2.el7.x86_64","Experimental":true}
[root@host34 system]#

通过remote api取得image list

通过images/json来取得image列表

[root@host34 system]# curl http://192.168.32.34:2375/images/json
[{
   "Id":"sha256:6a6aaff36c0e44069f53cb24325df1ab94ed1f8728fbf9d27a7dad77a0bb40e1","ParentId":"sha256:8bb55b6d05b4ad4b28f88d85d924c70456ba2154143cba35dd7941f225856b63","RepoTags":["harbor_log:latest"],"RepoDigests":null,"Created":1471476367,"Size":187937470,"VirtualSize":187937470,"Labels":{}},{
   "Id":"sha256:97701402d89b48ad96d546e2f6d31d85c0dfa14b62fc2d198df683203e316487","ParentId":"","RepoTags":["sonarqube:latest"],"RepoDigests":["sonarqube@sha256:88845581b9d2ece8822c610f3430769d638298784a421186fe41850a7311bd31"],"Created":1470946631,"Size":790910817,"VirtualSize":790910817,"Labels":{}},{
   "Id":"sha256:f8d79ba03c00bbcd8079cf05b7526ac8f4f422744aad8c3747a29a38ed8c4a41","ParentId":"","RepoTags":["ubuntu:latest"],"RepoDigests":["ubuntu@sha256:8e2324f2288c26e1393b63e680ee7844202391414dbd48497e9a4fd997cd3cbf"],"Created":1470937589,"Size":126368859,"VirtualSize":126368859,"Labels":{}},{
   "Id":"sha256:ff60113363279ed0eb02aadd3149368b414dcf9baa4d3ce3c1fc8b6f4a03875e","ParentId":"","RepoTags":["ubuntu:14.04"],"RepoDigests":["ubuntu@sha256:ef500a237fb51cea075b270d811601c7226097f61b34a8ed4b4aa4e350a2c66d"],"Created":1470937563,"Size":187935394,"VirtualSize":187935394,"Labels":{}},{
   "Id":"sha256:ddb795388d57a4e04872558c9bf9a8a16bd0fd86421575daadedc80ad4492db5","ParentId":"","RepoTags":["elasticsearch:latest"],"RepoDigests":["elasticsearch@sha256:6eecc2f2878a05bfc7a8f01e2b8f2f2ce8e5c3adb0799c8ef15248dbf1bb7815"],"Created":1470936135,"Size":345057490,"VirtualSize":345057490,"Labels":{}},{
   "Id":"sha256:2baf469627a99bf5391b9787e24c6cfddb501f42af87438958d3c2eb15d937d1","ParentId":"","RepoTags":["logstash:latest"],"RepoDigests":["logstash@sha256:5c8bcc7785eedf69043ec758d72fc3edc3a6a965067c87084168fff0eb534644"],"Created":1470856281,"Size":461494743,"VirtualSize":461494743,"Labels":{}},{
   "Id":"sha256:741f9784699093113c250d6669f9f61e22adfb8cce058bb5e7fa15ab6f497cff","ParentId":"","RepoTags":["kibana:latest"],"RepoDigests":["kibana@sha256:a32096e588ba49b87fd2e146d4d60aecb620219006afea1aa55e44528d127fa2"],"Created":1470263992,"Size":297003643,"VirtualSize":297003643,"Labels":{}},{
   "Id":"sha256:2b8fd9751c4c0f5dd266fcae00707e67a2545ef34f9a29354585f93dac906749","ParentId":"","RepoTags":["busybox:latest"],"RepoDigests":["busybox@sha256:a59906e33509d14c036c8678d687bd4eec81ed7c4b8ce907b888c607f6a1e0e6"],"Created":1466724217,"Size":1092588,"VirtualSize":1092588,"Labels":{}},{
   "Id":"sha256:0d409d33b27e47423b049f7f863faa08655a8c901749c2b25b93ca67d01a470d","ParentId":"","RepoTags":["nginx:latest"],"RepoDigests":["nginx@sha256:0fe6413f3e30fcc5920bc8fa769280975b10b1c26721de956e1428b9e2f29d04"],"Created":1464804059,"Size":182735995,"VirtualSize":182735995,"Labels":{}}]
[root@host34 system]#

注意点：设定之后，DOCKER_HOST也需要设定，不然正常的docker cli无法正常执行。

[root@host34 system]# export DOCKER_HOST=tcp://192.168.32.34:2375
[root@host34 system]# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
harbor_log          latest              6a6aaff36c0e        3 days ago          187.9 MB
sonarqube           latest              97701402d89b        9 days ago          790.9 MB
ubuntu              latest              f8d79ba03c00        9 days ago          126.4 MB
ubuntu              14.04               ff6011336327        9 days ago          187.9 MB
elasticsearch       latest              ddb795388d57        9 days ago          345.1 MB
logstash            latest              2baf469627a9        10 days ago         461.5 MB
kibana              latest              741f97846990        2 weeks ago         297 MB
busybox             latest              2b8fd9751c4c        8 weeks ago         1.093 MB
nginx               latest              0d409d33b27e        11 weeks ago        182.7 MB
[root@host34 system]#

取得container list

没有container时，取得空的列表

[root@host34 system]# docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
[root@host34 system]#
[root@host34 system]# curl http://192.168.32.34:2375/containers/json
[]
[root@host34 system]#

启动一个container

[root@host34 system]# docker run -d nginx
7736b16a2b78a420cdff1a5882579a071f55543f54d10856a2a06e20eca61d02
[root@host34 system]# docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS               NAMES
7736b16a2b78        nginx               "nginx -g 'daemon off"   9 seconds ago       Up 5 seconds        80/tcp, 443/tcp     thirsty_jang
[root@host34 system]#

确认结果

[root@host34 system]# curl http://192.168.32.34:2375/containers/json
[{
   "Id":"7736b16a2b78a420cdff1a5882579a071f55543f54d10856a2a06e20eca61d02","Names":["/thirsty_jang"],"Image":"nginx","ImageID":"sha256:0d409d33b27e47423b049f7f863faa08655a8c901749c2b25b93ca67d01a470d","Command":"nginx -g 'daemon off;'","Created":1471751666,"Ports":[{
   "PrivatePort":443,"Type":"tcp"},{
   "PrivatePort":80,"Type":"tcp"}],"Labels":{},"State":"running","Status":"Up 52 seconds","HostConfig":{
   "NetworkMode":"default"},"NetworkSettings":{
   "Networks":{
   "bridge":{
   "IPAMConfig":null,"Links":null,"Aliases":null,"NetworkID":"839a3e2f0e9c49cfa8e12c5eef8916ba85940d41ac43b81601366c63c70441b3","EndpointID":"d288b3f97d794e2a94bf14b8d233614116245cbfa3558bb780120049d75560e3","Gateway":"172.17.0.1","IPAddress":"172.17.0.2","IPPrefixLen":16,"IPv6Gateway":"","GlobalIPv6Address":"","GlobalIPv6PrefixLen":0,"MacAddress":"02:42:ac:11:00:02"}}},"Mounts":[]}]
[root@host34 system]#