Synnefo » snf-ganeti

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)

#. 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

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.

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