Add Ganeti 2.9 design document

[ganeti-local] / UPGRADE

Upgrade notes
=============

.. highlight:: shell-example

This document details the steps needed to upgrade a cluster to newer versions
of Ganeti.

As a general rule the node daemons need to be restarted after each software
upgrade; if using the provided example init.d script, this means running the
following command on all nodes::

    $ /etc/init.d/ganeti restart


2.1 and above
-------------

Starting with Ganeti 2.0, upgrades between revisions (e.g. 2.1.0 to 2.1.1)
should not need manual intervention. As a safety measure, minor releases (e.g.
2.1.3 to 2.2.0) require the ``cfgupgrade`` command for changing the
configuration version. Below you find the steps necessary to upgrade between
minor releases.

To run commands on all nodes, the `distributed shell (dsh)
<http://www.netfort.gr.jp/~dancer/software/dsh.html.en>`_ can be used, e.g.
``dsh -M -F 8 -f /var/lib/ganeti/ssconf_online_nodes gnt-cluster --version``.

#. Ensure no jobs are running (master node only)::

    $ gnt-job list

#. Pause the watcher for an hour (master node only)::

    $ gnt-cluster watcher pause 1h

#. Stop all daemons on all nodes::

    $ /etc/init.d/ganeti stop

#. Backup old configuration (master node only)::

    $ tar czf /var/lib/ganeti-$(date +\%FT\%T).tar.gz -C /var/lib ganeti

#. Install new Ganeti version on all nodes
#. Run cfgupgrade on the master node::

    $ /usr/lib/ganeti/tools/cfgupgrade --verbose --dry-run
    $ /usr/lib/ganeti/tools/cfgupgrade --verbose

   (``cfgupgrade`` supports a number of parameters, run it with
   ``--help`` for more information)

#. Upgrade the directory permissions on all nodes::

    $ /usr/lib/ganeti/ensure-dirs --full-run

#. Create the (missing) required users and make users part of the required
groups on all nodes::

    $ /usr/lib/ganeti/tools/users-setup

#. Restart daemons on all nodes::

    $ /etc/init.d/ganeti restart

#. Re-distribute configuration (master node only)::

    $ gnt-cluster redist-conf

#. If you use file storage, check that the ``/etc/ganeti/file-storage-paths``
   is correct on all nodes. For security reasons it's not copied
   automatically, but it can be copied manually via::

   $ gnt-cluster copyfile /etc/ganeti/file-storage-paths

#. Restart daemons again on all nodes::

    $ /etc/init.d/ganeti restart

#. Enable the watcher again (master node only)::

    $ gnt-cluster watcher continue

#. Verify cluster (master node only)::

    $ gnt-cluster verify

Reverting an upgrade
~~~~~~~~~~~~~~~~~~~~

For going back between revisions (e.g. 2.1.1 to 2.1.0) no manual
intervention is required, as for upgrades.

Starting from version 2.8, ``cfgupgrade`` supports ``--downgrade``
option to bring the configuration back to the previous stable version.
This is useful if you upgrade Ganeti and after some time you run into
problems with the new version. You can downgrade the configuration
without losing the changes made since the upgrade. Any feature not
supported by the old version will be removed from the configuration, of
course, but you get a warning about it. If there is any new feature and
you haven't changed from its default value, you don't have to worry
about it, as it will get the same value whenever you'll upgrade again.

The procedure is similar to upgrading, but please notice that you have to
revert the configuration **before** installing the old version.

#. Ensure no jobs are running (master node only)::

    $ gnt-job list

#. Pause the watcher for an hour (master node only)::

    $ gnt-cluster watcher pause 1h

#. Stop all daemons on all nodes::

    $ /etc/init.d/ganeti stop

#. Backup old configuration (master node only)::

    $ tar czf /var/lib/ganeti-$(date +\%FT\%T).tar.gz -C /var/lib ganeti

#. Run cfgupgrade on the master node::

    $ /usr/lib/ganeti/tools/cfgupgrade --verbose --downgrade --dry-run
    $ /usr/lib/ganeti/tools/cfgupgrade --verbose --downgrade

   You may want to copy all the messages about features that have been
   removed during the downgrade, in case you want to restore them when
   upgrading again.

#. Install the old Ganeti version on all nodes
#. Restart daemons on all nodes::

    $ /etc/init.d/ganeti restart

#. Re-distribute configuration (master node only)::

    $ gnt-cluster redist-conf

#. Restart daemons again on all nodes::

    $ /etc/init.d/ganeti restart

#. Enable the watcher again (master node only)::

    $ gnt-cluster watcher continue

#. Verify cluster (master node only)::

    $ gnt-cluster verify


2.0 releases
------------

2.0.3 to 2.0.4
~~~~~~~~~~~~~~

No changes needed except restarting the daemon; but rollback to 2.0.3 might
require configuration editing.

If you're using Xen-HVM instances, please double-check the network
configuration (``nic_type`` parameter) as the defaults might have changed:
2.0.4 adds any missing configuration items and depending on the version of the
software the cluster has been installed with, some new keys might have been
added.

2.0.1 to 2.0.2/2.0.3
~~~~~~~~~~~~~~~~~~~~

Between 2.0.1 and 2.0.2 there have been some changes in the handling of block
devices, which can cause some issues. 2.0.3 was then released which adds two
new options/commands to fix this issue.

If you use DRBD-type instances and see problems in instance start or
activate-disks with messages from DRBD about "lower device too small" or
similar, it is recoomended to:

#. Run ``gnt-instance activate-disks --ignore-size $instance`` for each
   of the affected instances
#. Then run ``gnt-cluster repair-disk-sizes`` which will check that
   instances have the correct disk sizes

1.2 to 2.0
----------

Prerequisites:

- Ganeti 1.2.7 is currently installed
- All instances have been migrated from DRBD 0.7 to DRBD 8.x (i.e. no
  ``remote_raid1`` disk template)
- Upgrade to Ganeti 2.0.0~rc2 or later (~rc1 and earlier don't have the needed
  upgrade tool)

In the below steps, replace :file:`/var/lib` with ``$libdir`` if Ganeti was not
installed with this prefix (e.g. :file:`/usr/local/var`). Same for
:file:`/usr/lib`.

Execution (all steps are required in the order given):

#. Make a backup of the current configuration, for safety::

    $ cp -a /var/lib/ganeti /var/lib/ganeti-1.2.backup

#. Stop all instances::

    $ gnt-instance stop --all

#. Make sure no DRBD device are in use, the following command should show no
   active minors::

    $ gnt-cluster command grep cs: /proc/drbd | grep -v cs:Unconf

#. Stop the node daemons and rapi daemon on all nodes (note: should be logged
   in not via the cluster name, but the master node name, as the command below
   will remove the cluster ip from the master node)::

    $ gnt-cluster command /etc/init.d/ganeti stop

#. Install the new software on all nodes, either from packaging (if available)
   or from sources; the master daemon will not start but give error messages
   about wrong configuration file, which is normal
#. Upgrade the configuration file::

    $ /usr/lib/ganeti/tools/cfgupgrade12 -v --dry-run
    $ /usr/lib/ganeti/tools/cfgupgrade12 -v

#. Make sure ``ganeti-noded`` is running on all nodes (and start it if
   not)
#. Start the master daemon::

    $ ganeti-masterd

#. Check that a simple node-list works::

    $ gnt-node list

#. Redistribute updated configuration to all nodes::

    $ gnt-cluster redist-conf
    $ gnt-cluster copyfile /var/lib/ganeti/known_hosts

#. Optional: if needed, install RAPI-specific certificates under
   :file:`/var/lib/ganeti/rapi.pem` and run::

    $ gnt-cluster copyfile /var/lib/ganeti/rapi.pem

#. Run a cluster verify, this should show no problems::

    $ gnt-cluster verify

#. Remove some obsolete files::

    $ gnt-cluster command rm /var/lib/ganeti/ssconf_node_pass
    $ gnt-cluster command rm /var/lib/ganeti/ssconf_hypervisor

#. Update the xen pvm (if this was a pvm cluster) setting for 1.2
   compatibility::

    $ gnt-cluster modify -H xen-pvm:root_path=/dev/sda

#. Depending on your setup, you might also want to reset the initrd parameter::

    $ gnt-cluster modify -H xen-pvm:initrd_path=/boot/initrd-2.6-xenU

#. Reset the instance autobalance setting to default::

    $ for i in $(gnt-instance list -o name --no-headers); do \
       gnt-instance modify -B auto_balance=default $i; \
      done

#. Optional: start the RAPI demon::

    $ ganeti-rapi

#. Restart instances::

    $ gnt-instance start --force-multiple --all

At this point, ``gnt-cluster verify`` should show no errors and the migration
is complete.

1.2 releases
------------

1.2.4 to any other higher 1.2 version
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

No changes needed. Rollback will usually require manual edit of the
configuration file.

1.2.3 to 1.2.4
~~~~~~~~~~~~~~

No changes needed. Note that going back from 1.2.4 to 1.2.3 will require manual
edit of the configuration file (since we added some HVM-related new
attributes).

1.2.2 to 1.2.3
~~~~~~~~~~~~~~

No changes needed. Note that the drbd7-to-8 upgrade tool does a disk format
change for the DRBD metadata, so in theory this might be **risky**. It is
advised to have (good) backups before doing the upgrade.

1.2.1 to 1.2.2
~~~~~~~~~~~~~~

No changes needed.

1.2.0 to 1.2.1
~~~~~~~~~~~~~~

No changes needed. Only some bugfixes and new additions that don't affect
existing clusters.

1.2.0 beta 3 to 1.2.0
~~~~~~~~~~~~~~~~~~~~~

No changes needed.

1.2.0 beta 2 to beta 3
~~~~~~~~~~~~~~~~~~~~~~

No changes needed. A new version of the debian-etch-instance OS (0.3) has been
released, but upgrading it is not required.

1.2.0 beta 1 to beta 2
~~~~~~~~~~~~~~~~~~~~~~

Beta 2 switched the config file format to JSON. Steps to upgrade:

#. Stop the daemons (``/etc/init.d/ganeti stop``) on all nodes
#. Disable the cron job (default is :file:`/etc/cron.d/ganeti`)
#. Install the new version
#. Make a backup copy of the config file
#. Upgrade the config file using the following command::

    $ /usr/share/ganeti/cfgupgrade --verbose /var/lib/ganeti/config.data

#. Start the daemons and run ``gnt-cluster info``, ``gnt-node list`` and
   ``gnt-instance list`` to check if the upgrade process finished successfully

The OS definition also need to be upgraded. There is a new version of the
debian-etch-instance OS (0.2) that goes along with beta 2.

.. vim: set textwidth=72 :
.. Local Variables:
.. mode: rst
.. fill-column: 72
.. End: