今天也来点Docker，端口映射与容器互联

一、端口映射

1.1 概述

在启动容器的时候，如果不指定对应的参数，在容器外部是无法通过网络来访问容器内部的网络应用和服务的。
　　当容器中运行一些网络应用，要让外部访问这些应用时，可以通过-p或-P参数来指定端口映射。当使用-P(大写P)标记时，Docker会随机映射一个端口到内部容器开放的网络端口

1.2 随机端口

[root@server5 apache]# docker run -d -P httpd:centos 
98cbed7ab7d0a4b8e7246ec1e5c7f626d3a8694978ef2cc7bc77c6855b4c5bb7
[root@server5 apache]# docker ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS                   NAMES
98cbed7ab7d0        httpd:centos        "/run.sh"           9 seconds ago       Up 8 seconds        0.0.0.0:32768->80/tcp   laughing_clarke

1.3 映射指定端口

[root@server5 apache]# docker run -d -p 4928:80 httpd:centos 
1257ec0883fa9ab4658841fbfcafde6ef4483c07b3be4a655a78e5f33477d370
[root@server5 apache]# docker ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS                   NAMES
1257ec0883fa        httpd:centos        "/run.sh"           3 seconds ago       Up 2 seconds        0.0.0.0:4928->80/tcp    happy_pasteur
98cbed7ab7d0        httpd:centos        "/run.sh"           3 minutes ago       Up 3 minutes        0.0.0.0:32768->80/tcp   laughing_clarke

二、容器互联

[root@server5 apache]# docker run -itd -P --name web11 centos:7 /bin/bash
06272630e7d46e721451f661b7e93658bcaeee3db0184b7ec9fad2e2d1fa63e1
[root@server5 apache]# docker run -itd -P --name web22 --link web11:web11 centos:7 /bin/bash
4f49ed7bed51fe68d64f5f6986f743b632b7a85af9fe5d1d91f8dc3bce6be54b
[root@server5 apache]# docker ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS                   NAMES
4f49ed7bed51        centos:7            "/bin/bash"         37 seconds ago      Up 36 seconds                               web22
06272630e7d4        centos:7            "/bin/bash"         3 minutes ago       Up 3 minutes                                web11
1257ec0883fa        httpd:centos        "/run.sh"           10 minutes ago      Up 10 minutes       0.0.0.0:4928->80/tcp    happy_pasteur
98cbed7ab7d0        httpd:centos        "/run.sh"           14 minutes ago      Up 14 minutes       0.0.0.0:32768->80/tcp   laughing_clarke
[root@server5 apache]# docker exec -it 4f49ed7bed51 /bin/bash
[root@4f49ed7bed51 /]# ping web11