root / README @ 6ef35e3c
History | View | Annotate | Download (2 kB)
| 1 |
Ganeti Cluster tools (htools) |
|---|---|
| 2 |
============================= |
| 3 |
|
| 4 |
These are some simple cluster tools for fixing common problems. Right |
| 5 |
now N+1 and rebalancing are included. |
| 6 |
|
| 7 |
|
| 8 |
Cluster N+1 solver |
| 9 |
------------------ |
| 10 |
|
| 11 |
This program runs a very simple brute force algorithm over the instance |
| 12 |
placement space in order to determine the shortest number of replace-disks |
| 13 |
needed to fix the cluster. Note this means we won't get a balanced cluster, |
| 14 |
just one that passes N+1 checks. |
| 15 |
|
| 16 |
For algorithm details and usage, see the man page hn1(1). |
| 17 |
|
| 18 |
Cluster rebalancer |
| 19 |
------------------ |
| 20 |
|
| 21 |
Compared to the N+1 solver, the rebalancer uses a very simple algorithm: |
| 22 |
repeatedly try to move each instance one step, so that the cluster score |
| 23 |
becomes better. We stop when no further move can improve the score. |
| 24 |
|
| 25 |
For algorithm details and usage, see the man page hbal(1). |
| 26 |
|
| 27 |
Integration with Ganeti |
| 28 |
----------------------- |
| 29 |
|
| 30 |
The programs can either get their input from text files, or online |
| 31 |
from a cluster via RAPI. For online collection via RAPI, the "-m" |
| 32 |
argument to both hn1 and hbal should specify the cluster or master |
| 33 |
node name. |
| 34 |
|
| 35 |
For text files, a separate tool (hscan) is provided to automate their |
| 36 |
gathering if RAPI is available, which is better since it can extract |
| 37 |
more precise information. In case RAPI is not usable for whatever |
| 38 |
reason, the following two commands should be run:: |
| 39 |
|
| 40 |
gnt-node list -oname,mtotal,mnode,mfree,dtotal,dfree \ |
| 41 |
--separator '|' --no-headers > nodes |
| 42 |
gnt-instance list -oname,admin_ram,sda_size,status,pnode,snodes \ |
| 43 |
--separator '|' --no-head > instances |
| 44 |
|
| 45 |
These two files should be saved under the names of *nodes* and *instances*. |
| 46 |
|
| 47 |
Installation |
| 48 |
------------ |
| 49 |
|
| 50 |
If installing from source, you need a working ghc compiler (6.8 at |
| 51 |
least) and some extra Haskell libraries which usually need to be |
| 52 |
installed manually: |
| 53 |
|
| 54 |
- json |
| 55 |
- curl |
| 56 |
|
| 57 |
One these are available, just typing *make* in the top-level directory |
| 58 |
should be enough. |
| 59 |
|
| 60 |
Internal (implementation) documentation is available in the ``apidoc`` |
| 61 |
directory. |