03- Docker Beginner - Port Forwarding/Mapping

Summary:

I have CentOS container named "centos1" that have HTTP server.
I want to forward incoming request to port 8081 on the docker physcial host to port 80 on the 'centos' container.

Install 'httpd' on 'centos1' container:

[root@docker1 ~]# hostname
docker1.ab.lab

[root@docker1 ~]# docker ps -s
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES               SIZE
766f948a89d6        centos              "/bin/bash"         2 hours ago         Up 41 minutes                           centos1             217 MB (virtual 416 MB)

[root@docker1 ~]# docker attach centos1

[root@766f948a89d6 /]# ip a
1: lo:  mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
26: eth0@if27:  mtu 1500 qdisc noqueue state UP group default 
    link/ether 02:42:ac:11:00:02 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 172.17.0.2/16 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::42:acff:fe11:2/64 scope link 
       valid_lft forever preferred_lft forever

[root@766f948a89d6 /]# yum install httpd -y 

[root@766f948a89d6 /]# systemctl enable httpd      

[root@766f948a89d6 /]# httpd &
[1] 59

[root@766f948a89d6 /]# ps -ef | grep httpd
root        60     1  0 12:18 ?        00:00:00 httpd
apache      61    60  0 12:18 ?        00:00:00 httpd
apache      62    60  0 12:18 ?        00:00:00 httpd
apache      63    60  0 12:18 ?        00:00:00 httpd
apache      64    60  0 12:18 ?        00:00:00 httpd
apache      65    60  0 12:18 ?        00:00:00 httpd
root        67     1  0 12:18 ?        00:00:00 grep --color=auto httpd

[root@766f948a89d6 /]# netstat -tupenl          
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       User       Inode      PID/Program name    
tcp6       0      0 :::80                   :::*                    LISTEN      0          117163     60/httpd 

[root@766f948a89d6 /]# echo "httpd enabled on centos1 container" >> /var/www/html/index.html

[root@766f948a89d6 /]# lynx --dump 172.17.0.2
   httpd enabled on centos1 container

Redirect any incoming request to "docker1.ab.lab:8081" (physical docker host) to "766f948a89d6:80" (centos1 container):

[root@docker1 ~]# docker stop centos1 centos1 [root@docker1 ~]# docker run -it -p 8081:80 centos /bin/bash [root@docker1 ~]# docker ps -s CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES SIZE 43a3e1940071 centos "/bin/bash" 31 seconds ago Up 29 seconds 0.0.0.0:8081->80/tcp agitated_liskov 0 B (virtual 199 MB)