Red Hat Bugzilla – Bug 1475626
Change the default storage driver to overlay2
Last modified: 2017-11-20 19:13:32 EST
Description of problem:
Atomic Host currently defaults to devicemapper as the storage driver for docker. This needs to change to overlay2.
Version-Release number of selected component (if applicable):
So one thing I need to understand here - are we going to change what `docker` does by default for 7.5 or not? @rhvgoyal said to me something of the form "let's do kernel version checks"? Would we have something like
Alternatively of course we could just have separate 7.4 and 7.5 builds of docker, and anyone who does `yum update` on Extras without doing Server too is just broken?
We had a long chat about this on IRC; one foundational question here - is it PM's intention that this change *also* happens for yum-based RHEL? I'm assuming it is.
<vgoyal> walters: I think there is a problem there too. People might have assumed that default graph driver is devicemapper and specified put in other variables which are devicemapper specific.
<vgoyal> walters: so we will have to make sure that there are no devicemapper specific knobs in /etc/sysconfig/docker-storage-setup before we decide to switch to overlay2
<vgoyal> walters: also we might break a system which assumes that devicemapper is default. Over upgrade to css, they might suddenly see overlay2 as default.
Sorry I missed your question here. Yes, both RHEL & AH should be consistent with the defaults. I think it's best for new installs (yum & rpm-ostree) to default to overlay2, but for upgraded systems to continue as they were already configured (dm or whatever). After reading the PR, it seems like you guys came to the same conclusion.