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Merging clusters |
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================ |
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With ``cluster-merge`` from the ``tools`` directory it is possible to |
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merge two or more clusters into one single cluster. |
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If anything goes wrong at any point the script suggests you rollback |
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steps you've to perform *manually* if there are any. The point of no |
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return is when the master daemon is started the first time after merging |
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the configuration files. A rollback at this point would involve a lot of |
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manual work. |
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For the internal design of this tool have a look at the `Automated |
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Ganeti Cluster Merger <design-2.1.rst>` document. |
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Merge Clusters |
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============== |
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The tool has to be invoked on the cluster you like to merge the other |
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clusters into. |
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The usage of ``cluster-merge`` is as follows:: |
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cluster-merge [--debug|--verbose] [--watcher-pause-period SECONDS] \ |
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[--groups [merge|rename]] <cluster> [<cluster...>] |
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You can provide multiple clusters. The tool will then go over every |
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cluster in serial and perform the steps to merge it into the invoking |
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cluster. |
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These options can be used to control the behaviour of the tool: |
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``--debug``/``--verbose`` |
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These options are mutually exclusive and increase the level of output |
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to either debug output or just more verbose output like action |
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performed right now. |
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``--watcher-pause-period`` |
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Define the period of time in seconds the watcher shall be disabled, |
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default is 1800 seconds (30 minutes). |
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``--groups`` |
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This option controls how ``cluster-merge`` handles duplicate node |
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group names on the merging clusters. If ``merge`` is specified then |
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all node groups with the same name will be merged into one. If |
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``rename`` is specified, then conflicting node groups on the remove |
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clusters will have their cluster name appended to the group name. If |
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this option is not speicifed, then ``cluster-merge`` will refuse to |
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continue if it finds conflicting group names, otherwise it will |
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proceed as normal. |
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Rollback |
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======== |
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If for any reason something in the merge doesn't work the way it should |
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``cluster-merge`` will abort, provide an error message and optionally |
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rollback steps. Please be aware that after a certain point there's no |
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easy way to rollback the cluster to its previous state. If you've |
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reached that point the tool will not provide any rollback steps. |
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If you end up with rollback steps, please perform them before invoking |
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the tool again. It doesn't keep state over invokations. |
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.. vim: set textwidth=72 : |
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.. Local Variables: |
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.. mode: rst |
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.. fill-column: 72 |
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.. End: |