mirror of
https://github.com/ceph/ceph
synced 2024-12-12 06:28:31 +00:00
57 lines
2.1 KiB
ReStructuredText
57 lines
2.1 KiB
ReStructuredText
=====================
|
|
Add/Remove Monitors
|
|
=====================
|
|
|
|
With ``ceph-deploy``, adding and removing monitors is a simple task. You just
|
|
add or remove one or more monitors on the command line with one command. Before
|
|
``ceph-deploy``, the process of `adding and removing monitors`_ involved
|
|
numerous manual steps. Using ``ceph-deploy`` imposes a restriction: **you may
|
|
only install one monitor per host.**
|
|
|
|
.. note:: We do not recommend comingling monitors and OSDs on
|
|
the same host.
|
|
|
|
For high availability, you should run a production Ceph cluster with **AT
|
|
LEAST** three monitors. Ceph uses the Paxos algorithm, which requires a
|
|
consensus among the majority of monitors in a quorum. With Paxos, the monitors
|
|
cannot determine a majority for establishing a quorum with only two monitors. A
|
|
majority of monitors must be counted as such: 1:1, 2:3, 3:4, 3:5, 4:6, etc.
|
|
|
|
See `Monitor Config Reference`_ for details on configuring monitors.
|
|
|
|
|
|
Add a Monitor
|
|
=============
|
|
|
|
Once you create a cluster and install Ceph packages to the monitor host(s), you
|
|
may deploy the monitor(s) to the monitor host(s). When using ``ceph-deploy``,
|
|
the tool enforces a single monitor per host. ::
|
|
|
|
ceph-deploy mon create {host-name [host-name]...}
|
|
|
|
|
|
.. note:: Ensure that you add monitors such that they may arrive at a consensus
|
|
among a majority of monitors, otherwise other steps (like ``ceph-deploy gatherkeys``)
|
|
will fail.
|
|
|
|
.. note:: When adding a monitor on a host that was not in hosts initially defined
|
|
with the ``ceph-deploy new`` command, a ``public network`` statement needs
|
|
to be added to the ceph.conf file.
|
|
|
|
Remove a Monitor
|
|
================
|
|
|
|
If you have a monitor in your cluster that you'd like to remove, you may use
|
|
the ``destroy`` option. ::
|
|
|
|
ceph-deploy mon destroy {host-name [host-name]...}
|
|
|
|
|
|
.. note:: Ensure that if you remove a monitor, the remaining monitors will be
|
|
able to establish a consensus. If that is not possible, consider adding a
|
|
monitor before removing the monitor you would like to take offline.
|
|
|
|
|
|
.. _adding and removing monitors: ../../operations/add-or-rm-mons
|
|
.. _Monitor Config Reference: ../../configuration/mon-config-ref
|