Docker守護進程提供了一套遠程REST API，具體可以參考文檔：https://docs.docker.com/engine/reference/api/docker_remote_api/
這套API是提供給客戶端與Docker引擎通信時使用，這套API也可以由其他工具調用，比如curl或Chrome浏覽器的Postman REST客戶端工具。
如果是在Mac OSX Mavericks系統上使用Docker機創建Docker守護進程，那麼要啟用Docker遠程API功能需要一定的技巧。下面一一道來。
可以使用curl工具連接到安全的Docker端口，命令如下：
$ curl https://$HOST:2376/images/json
--cert ~/.docker/cert.pem
--key ~/.docker/key.pem
--cacert ~/.docker/ca.pem
此命令存在一定的問題。主要有：
1）命令可能不工作，因為每一個Docker機的證書存儲在.docker/machine/machines/目錄。
2）即使命令根據路徑做了修改，比如：
curl https://192.168.99.100:2376/images/json --cert $DOCKER_CERT_PATH/cert.pem --key $DOCKER_CERT_PATH/key.pem --cacert $DOCKER_CERT_PATH/ca.pem
執行命令仍然會得到錯誤信息：
curl: (58) SSL: Can't load the certificate "/Users/arungupta/.docker/machine/machines/couchbase/cert.pem" and its private key: OSStatus -25299
解決方法是需要更新curl工具。總的來說，最新版的curl工具使用了Apple的安全傳輸層API（Secure Transport API），取代了原先的OpenSSL API。這意味著證書必須是p12格式。
下面可以這樣修復命令：
1）進入Docker機存放證書的目錄，比如.docker/machine/machines/couchbase目錄
2）生成*.p12格式的證書
openssl pkcs12 -export
-inkey key.pem
-in cert.pem
-CAfile ca.pem
-chain
-name client-side
-out cert.p12
-password pass:mypass
現在可以調用REST API了：
curl https://192.168.99.100:2376/images/json --cert $DOCKER_CERT_PATH/cert.p12 --pass mypass --key $DOCKER_CERT_PATH/key.pem --cacert $DOCKER_CERT_PATH/ca.pem
注意，–cert參數現在指向了生成的p12證書，證書的密碼使用–pass參數進行指定。
然後會得到如下結果：
[{"Id":"sha256:d38beda529d3274636d6cb1c9000afe4f00fbdcfa544140d6cc0f5d7f5b8434a","ParentId":"","RepoTags":["arungupta/couchbase:latest"],"RepoDigests":null,"Created":1450330075,"Size":374824677,"VirtualSize":374824677,"Labels":{}}]
現在可以嘗試啟動CouchBase服務器：
~ > docker run -d -p 8091-8093:8091-8093 -p 11210:11210 arungupta/couchbase
42d1414883affd0fbb272cb1378c2f6b5118acf3ed5cb60cbecdc42f95602e3e
再調用另一個REST API來查看容器的細節內容：
~ > curl https://192.168.99.100:2376/containers/json --cert $DOCKER_CERT_PATH/cert2.p12 --pass mypass --key $DOCKER_CERT_PATH/key.pem --cacert $DOCKER_CERT_PATH/ca.pem
[{"Id":"42d1414883affd0fbb272cb1378c2f6b5118acf3ed5cb60cbecdc42f95602e3e","Names":["/admiring_pike"],"Image":"arungupta/couchbase","ImageID":"sha256:d38beda529d3274636d6cb1c9000afe4f00fbdcfa544140d6cc0f5d7f5b8434a","Command":"/entrypoint.sh /opt/couchbase/configure-cluster.sh","Created":1454850194,"Ports":[{"IP":"0.0.0.0","PrivatePort":8092,"PublicPort":8092,"Type":"tcp"},{"PrivatePort":11207,"Type":"tcp"},{"IP":"0.0.0.0","PrivatePort":11210,"PublicPort":11210,"Type":"tcp"},{"PrivatePort":18092,"Type":"tcp"},{"PrivatePort":18091,"Type":"tcp"},{"IP":"0.0.0.0","PrivatePort":8093,"PublicPort":8093,"Type":"tcp"},{"IP":"0.0.0.0","PrivatePort":8091,"PublicPort":8091,"Type":"tcp"},{"PrivatePort":11211,"Type":"tcp"}],"Labels":{},"Status":"Up 2 seconds","HostConfig":{"NetworkMode":"default"},"NetworkSettings":{"Networks":{"bridge":{"IPAMConfig":null,"Links":null,"Aliases":null,"NetworkID":"","EndpointID":"6feaf4c1c70feaf0ba240ce55fb58ce83ebb84c8098bef9171998e84f607fa0b","Gateway":"172.17.0.1","IPAddress":"172.17.0.2","IPPrefixLen":16,"IPv6Gateway":"","GlobalIPv6Address":"","GlobalIPv6PrefixLen":0,"MacAddress":"02:42:ac:11:00:02"}}}}]
