Create RPM Ostree Repo

# cd /srv/rpm-ostree
# mkdir repo
# ostree --repo=repo init --mode=archive-z2

Create treefiles

Base

fedora-moximo.json

{
    "ref": "fedora-moximo/f22/armv7hl/base/core",

    "gpg_key": "<SET KEY ID FOR GPG>",

    "repos": ["fedora", "fedora-updates"],

    "selinux": true,

    "bootstrap_packages": ["filesystem", "glibc", "nss-altfiles", "shadow-utils",
                           "generic-release"],

    "packages": ["kernel", "ostree", "lvm2", 
                 "btrfs-progs", "e2fsprogs", "xfsprogs",
                 "gnupg2", "selinux-policy-targeted",
                 "openssh-server", "openssh-clients",
                 "NetworkManager", "vim-minimal", "nano", "sudo"]
}

fedora-moximo-docker.json

{
    "ref": "fedora-atomic/rawhide/x86_64/server/docker",

    "include": "fedora-rawhide-base.json",

    "packages": ["docker-io"],
    
    "units": ["docker.service", "docker.socket"]
}

Create the repo

# rpm-ostree compose tree --repo=/srv/rpm-ostree/repo --proxy=http://127.0.0.1:8123 sometreefile.json

http://patrick.uiterwijk.org/2014/01/21/rpm-ostree/
https://github.com/cgwalters/rpm-ostree/blob/master/doc/compose-server.md