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Ganeti Cluster tools (htools) |
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============================= |
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These are some simple cluster tools for fixing common problems. Right |
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now N+1 and rebalancing are included. Starting with version 0.1.0, |
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only Ganeti 2.0 is supported. |
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Cluster N+1 solver |
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------------------ |
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This program runs a very simple brute force algorithm over the instance |
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placement space in order to determine the shortest number of replace-disks |
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needed to fix the cluster. Note this means we won't get a balanced cluster, |
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just one that passes N+1 checks. |
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For algorithm details and usage, see the man page hn1(1). |
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Cluster rebalancer |
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------------------ |
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Compared to the N+1 solver, the rebalancer uses a very simple algorithm: |
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repeatedly try to move each instance one step, so that the cluster score |
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becomes better. We stop when no further move can improve the score. |
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For algorithm details and usage, see the man page hbal(1). |
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Integration with Ganeti |
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----------------------- |
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The programs can either get their input from text files, or online |
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from a cluster via RAPI. For online collection via RAPI, the "-m" |
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argument to both hn1 and hbal should specify the cluster or master |
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node name. |
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For text files, a separate tool (hscan) is provided to automate their |
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gathering if RAPI is available, which is better since it can extract |
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more precise information. In case RAPI is not usable for whatever |
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reason, the following two commands should be run:: |
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gnt-node list -oname,mtotal,mnode,mfree,dtotal,dfree,offline \ |
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--separator '|' --no-headers > nodes |
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gnt-instance list -oname,admin_ram,sda_size,status,pnode,snodes \ |
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--separator '|' --no-head > instances |
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These two files should be saved under the names of *nodes* and *instances*. |
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Installation |
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------------ |
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If installing from source, you need a working ghc compiler (6.8 at |
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least) and some extra Haskell libraries which usually need to be |
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installed manually: |
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- json |
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- curl |
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One these are available, just typing *make* in the top-level directory |
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should be enough. |
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Internal (implementation) documentation is available in the ``apidoc`` |
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directory. |