Doing learning example web-based voting application

General Discussions
1

Hi
Im pretty new to Docker

I’m trying to follow the Docker get started example and has come to the section about creating a web-based voting application.
However the part about “Set up Dockerized machines” only talks about Mac and windows machines.
It’s a bit confusing when doing the exercise on Linux. Can anyone explain how to do this on a Centos7 machine?
I have downloaded the docker-machine to my centos machine. But I’m not sure what --driver to specify ?

Perhaps I misunderstood something

thanks in advance
Ulrik

2

Hi,

Do you follow this steps before? >> https://docs.docker.com/machine/install-machine/

3

yes, I followed the steps in the link to install Docker-machine on my centos

4

In my case I just follow the tutorial using MAC command.

I finished now.

Really is very confused

I use fedora.

5

ok thanks. did you use the docker-machine create command with virtualbox?

I tried It , but got an error message returned

[ulrik@localhost ~]$ docker-machine create --driver virtualbox manager
Creating CA: /home/ulrik/.docker/machine/certs/ca.pem
Creating client certificate: /home/ulrik/.docker/machine/certs/cert.pem
Running pre-create checks…
Error with pre-create check: “VBoxManage not found. Make sure VirtualBox is installed and VBoxManage is in the path”
[ulrik@localhost ~]$

6

have a discussion about this here, maybe help you

7

Thanks. I will check it out :+1:

8

Of course, you don’t need to use docker-machine at all. Just setup two linux machines and install Docker on them. Then go from there.

I happen to like Digitalocean, and did the voting machine demo by creating two “droplets” from their Docker “One Click App” based on the Ubuntu 14.04 image. Don’t use the 16.04 image as it has locked down the ports needed for the Swarm cluster to work.and will cause you much grief because the workers will time out trying and not be able to join the Swarm.

Actually Digital Ocean has some good documentation and they do explain how to fix the port issue here: https://www.digitalocean.com/community/tutorials/how-to-configure-the-linux-firewall-for-docker-swarm-on-ubuntu-16-04

9

Thanks for your input. I was thinking about that posibility, since I have a extra centos7 machine available on my network. So is it just to skip the “set up Dockerized machines” section and continue in “Create a swarm” section ?