Synnefo » snf-ganeti

upgrade (or downgrade) to, given as full string with major, minor, suffix,

and suffix. To be compatible with current configuration upgrade and downgrade

procedures, the new version must be of the same major version and

either an equal or higher minor version, or precisely the previous

minor version.

- It verifies that the version to change to is installed on all nodes

  of the cluster that are not marked as offline. If this is not the

- An intent-to-upgrade file is created that contains the current

  version of ganeti, the version to change to, and the process ID of

  but allows manual detection if the upgrade process died

  unintentionally. The intend-to-upgrade file is persisted to disk

  before continuing.

- A backup of all Ganeti-related status information is created for

  manual rollbacks. While the normal way of rolling back after an

  with the older version as argument, a full backup provides an

  additional safety net, especially for jump-upgrades (skipping

  intermediate minor versions).

=======================================================

During the upgrade procedure, the only ganeti process still running is

for eventually removing the queue drain. Therefore, we have to provide

means to resume this process, if it dies unintentionally. The process

itself will handle SIGTERM gracefully by either undoing all changes

through to the end), or not (in which case the actions done so far are

rolled back).

it is running on the master node, using the same requirement as for

starting the master daemon, i.e., confirmed by a majority of all

nodes. If it is not the master node, it will remove any possibly

resume at the appropriate stage.

- If the configuration file still is at the initial version,

  writing of the intend-to-upgrade file. It should be noted that

  all steps before changing the configuration are idempotent, so

  redoing them does not do any harm.

Caveats

=======

information about a previous drain gets lost. This problem will

disappear, once :doc:`design-optables` is implemented, as then the

undrain will then be restricted to filters by gnt-upgrade.