Add support for CentOS 7 or newer to mup

[msteinmn]

This is to use mup on CentOS VMs as many enterprises still standardize on RedHat Linux. mup has very few dependencies on the distribution. Tested on Google cloud images.

[msteinmn]

This seems to work fine with CentOS 7 based VMs, like from Google Compute. The only real requirement for a CentOS host is that it can properly run Docker. The rest of mup then is unaffected by the distro (so it seems anyway).

Creating a test environment in Travis CI is more difficult. I would need a container analogous to phusion/baseimage-docker but built on CentOS. The default CentOS containers do not seem to properly support running docker-in-docker. Using DIND defeats the purpose of creating a realistic test it seems. If anyone has any ideas, let me know.

[allan-avatar1]

Thanks for uploading this, appreciate it. Any ideas why it wasn't merged by the team? Seems like a great patch

[zodern]

Thanks for working on this @msteinmn. I would like to find a way to automate tests with centos before merging so we can ensure it doesn't break in the future. I will experiment with docker in docker and cent os.

[kulttuuri]

Any updates on this? :)

[kulttuuri]

I just went ahead and tried this on centOS 7 (exact version was CentOS Linux release 7.7.1908). Here are my steps and problems encountered:

1. Ran mup init. No problems.
2. Configured mup settings to correct values.
3. Ran mup setup. Now it exploded.
4. First, setup started complaining about lsb_release on the server. CentOS by default does not have lsb_release installed, so I installed it with this command: yum install redhat-lsb. Now it continued...
5. Now I run mup setup again. Now it started complaining about Docker in the docker_install.sh script. I didn't figure out why it's doing this, so I just went ahead and installed Docker with this command: curl -fsSL https://get.docker.com/ | sh.
6. Ran mup setup again. Now it went through correctly. After this, ran mup deploy and it worked (just had to do the sudo nopasswd song and dance to actually deploy). Now the app is deployed and all working! :)

So - couple problems encountered alongside the way here. lsb_release not in centos by default and Docker is installed check / or installation failed. Also, not sure if it is related, but I fixed the nopasswd thing AFTER I got the mup setup to go through, so it could be related to problems in mup setup phase.