在Mac OS X上将应用程序码头化

Question

I installed boot2docker as explained on the docker website. Here are some command runs to show that I have things installed correctly:

$$:~ kv$ boot2docker start
Waiting for VM and Docker daemon to start...
...................ooo
Started.
Writing /Users/kvantum/.boot2docker/certs/boot2docker-vm/ca.pem
Writing /Users/kvantum/.boot2docker/certs/boot2docker-vm/cert.pem
Writing /Users/kvantum/.boot2docker/certs/boot2docker-vm/key.pem
Your environment variables are already set correctly.

$$:~ kv$ docker images
REPOSITORY  TAG     IMAGE ID        CREATED             VIRTUAL SIZE
ubuntu     14.04   b39b81afc8ca        11 days ago         188.3 MB
hello-world  latest e45a5af57b00        3 weeks ago         910 B

After this, I ran the following command:

docker run -t -i ubuntu:14.04 /bin/bash

Inside the container, I installed zeromq, and started a zeromq server on port 5555 using tcp.

My questions are following:

1. If I exit out of the container, will it save all the work I do inside it?

2. I have no idea how to connect to the server running on port 5555. I read something about exposing a port, but I am not sure how to go about doing that. I did an ifconfig inside the container, and tried to connect to the server from the host like this:

    $$:~ kv$ ./zmq_client tcp://container_ip:5555 

   This did not work. Can someone please lists the steps I need to take in order to connect to the server running within the container.

For completion sake, I am providing the list of my environment variables:

TERM_PROGRAM=Apple_Terminal
TERM=xterm-256color
SHELL=/bin/bash
TMPDIR=/var/folders/km/5kbpdx4s7cg4rmyc6d5q9l9r0000gq/T/
DOCKER_HOST=tcp://192.168.109.103:2376
Apple_PubSub_Socket_Render=/tmp/launch-1tWMHJ/Render
TERM_PROGRAM_VERSION=326
OLDPWD=/Users
TERM_SESSION_ID=262CBC8B-0A74-4B70-9F28-D9FA51FF713C
USER=kv
SSH_AUTH_SOCK=/tmp/launch-ZTWNGL/Listeners
__CF_USER_TEXT_ENCODING=0x1F7:0:0
DOCKER_TLS_VERIFY=1
__CHECKFIX1436934=1
PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/opt/X11/bin
PWD=/Users/kv
DOCKER_CERT_PATH=/Users/kv/.boot2docker/certs/boot2docker-vm
HOME=/Users/kv
SHLVL=1
LOGNAME=kv
LC_CTYPE=UTF-8
DISPLAY=/tmp/launch-rco9zt/org.macosforge.xquartz:0
_=/usr/bin/env

One last question I have is about code performance. So within my Mac OS X, I have a docker container running (which runs Ubuntu). If I run the application, like a zeromq based server inside the container, will it not be slower as compared to running it on Mac OS X directly. Please explain the benefits of using docker in such a scenario..

Answer 1

You should really do some more reading and research before turning to SO, then ask about anything you can't figure out. But:

1. No. If the container is "exited" you can restart it and your files will still be there, but once it is removed your files are gone. You can use docker commit to save them to an image, but the best bet is to use a Dockerfile.

2. docker run -p 5000:8000 image will expose port 8000 in the container as port 5000 on the host.

3. Yes, it will be slower due to the boot2docker VM. It would not be slower if you were running on a Linux host. The advantage is that zeromq is now running in an isolated container with all its dependencies.