EPEL requirement on CentOS is only because of leveldb

[David Moreau Simard]

Just wanted to document this somewhere.

Installing Ceph requires leveldb. leveldb is not included in the main CentOS repositories and thus is fetched from EPEL.
This makes installing Ceph from the official repositories impossible unless enabling EPEL.

CentOS provides a Ceph repository through it's Storage SIG initiative:
- https://wiki.centos.org/SpecialInterestGroup/Storage/
- https://github.com/CentOS-Storage-SIG/ceph

The generated repositories include the required leveldb package, ex: http://cbs.centos.org/repos/storage7-ceph-hammer-candidate/x86_64/os/Packages/

It feels silly that EPEL is required for the "official" way of installing Ceph but it looks like this won't be fixed in the short term.

[David Moreau Simard (dmsimard)]

The SIG repos are officially available in CentOS 7:

# yum install centos-release-ceph
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirror.ci.centos.org
 * extras: mirror.ci.centos.org
 * updates: mirror.ci.centos.org
Resolving Dependencies
--> Running transaction check
---> Package centos-release-ceph-hammer.noarch 0:1.0-5.el7.centos will be installed
--> Processing Dependency: centos-release-storage-common for package: centos-release-ceph-hammer-1.0-5.el7.centos.noarch
--> Running transaction check
---> Package centos-release-storage-common.noarch 0:1-2.el7.centos will be installed
--> Finished Dependency Resolution

Dependencies Resolved

==============================================================================================================================================================================================================================================================================================================================
 Package Arch Version Repository Size
==============================================================================================================================================================================================================================================================================================================================
Installing:
 centos-release-ceph-hammer noarch 1.0-5.el7.centos extras 4.5 k
Installing for dependencies:
 centos-release-storage-common noarch 1-2.el7.centos extras 4.5 k

Transaction Summary
==============================================================================================================================================================================================================================================================================================================================
Install 1 Package (+1 Dependent package)

Total download size: 9.1 k
Installed size: 2.0 k
Is this ok [y/d/N]:

[John Trowbridge (trown)]

"Official" way of installing ceph on CentOS is using storage sig repo.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/304808

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/304808
Committed: https://git.openstack.org/cgit/openstack/puppet-ceph/commit/?id=e13f3d55e17a632364aaa81ee97f0dc97f131e8e
Submitter: Jenkins
Branch: master

commit e13f3d55e17a632364aaa81ee97f0dc97f131e8e
Author: Emilien Macchi <email address hidden>
Date: Tue Apr 12 13:45:40 2016 -0400

    repo: add support for CentOS SIG

    CentOS SIG [1] is currently a reference to deploy Ceph packages on
    CentOS operating system. They provide all we need without using EPEL &
    ceph.com repositories.

    Some use-cases (with OpenStack) want to avoid deploying EPEL repository,
    so CentOS SIG is very helpful for that, by providing supported
    packaging.

    This patch adds a new boolean, false by default for backward
    compatibility:
    enable_sig

    When True, centos-release-ceph rpm will be installed before any other
    ceph package in the Puppet catalog. Also, repositories from ceph.com
    won't be installed at all

    We don't add a complex logic where we lock a specific operating system
    but still send a warning if we try to enable SIG on something else than
    CentOS (still Red Hat operating system though). Also, even if not
    suggested, we don't check if EPEL is enabled or not.
    The logic keeps things simple: allow Red Hat users to choose between
    ceph.com and SIG. Also keep the possibility to allow EPEL or not.

    [1] https://wiki.centos.org/SpecialInterestGroup/Storage/

    Change-Id: Ic42c19b2b5b4bc499565c69c3053395173c29a8e
    Closes-Bug: #1562998