root / man / hroller.rst @ 313fdabc
History | View | Annotate | Download (2.5 kB)
| 1 |
HROLLER(1) Ganeti | Version @GANETI_VERSION@ |
|---|---|
| 2 |
============================================ |
| 3 |
|
| 4 |
NAME |
| 5 |
---- |
| 6 |
|
| 7 |
hroller \- Cluster rolling maintenance scheduler for Ganeti |
| 8 |
|
| 9 |
SYNOPSIS |
| 10 |
-------- |
| 11 |
|
| 12 |
**hroller** {backend options...} [algorithm options...] [reporting options...]
|
| 13 |
|
| 14 |
**hroller** \--version |
| 15 |
|
| 16 |
|
| 17 |
Backend options: |
| 18 |
|
| 19 |
{ **-m** *cluster* | **-L[** *path* **]** | **-t** *data-file* |
|
| 20 |
**-I** *path* } |
| 21 |
|
| 22 |
**[ --force ]** |
| 23 |
|
| 24 |
Algorithm options: |
| 25 |
|
| 26 |
**[ -G *name* ]** |
| 27 |
|
| 28 |
**[ -O *name...* ]** |
| 29 |
|
| 30 |
**[ --node-tags** *tag,..* **]** |
| 31 |
|
| 32 |
Reporting options: |
| 33 |
|
| 34 |
**[ -v... | -q ]** |
| 35 |
**[ -S *file* ]** |
| 36 |
|
| 37 |
DESCRIPTION |
| 38 |
----------- |
| 39 |
|
| 40 |
hroller is a cluster maintenance reboot scheduler. It can calculate |
| 41 |
which set of nodes can be rebooted at the same time while avoiding |
| 42 |
having both primary and secondary nodes being rebooted at the same time. |
| 43 |
|
| 44 |
For backends that support identifying the master node (currenlty |
| 45 |
RAPI and LUXI), the master node is scheduled as the last node |
| 46 |
in the last reboot group. |
| 47 |
|
| 48 |
ALGORITHM FOR CALCULATING OFFLINE REBOOT GROUPS |
| 49 |
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| 50 |
|
| 51 |
hroller will view the nodes as vertices of an undirected graph, |
| 52 |
connecting by instances which have both a primary and a secondary node. |
| 53 |
It will then color the graph using a few different heuristics, and |
| 54 |
return the minimum-size color set found. Node with the same color don't |
| 55 |
share an edge, and as such don't have an instance with both primary and |
| 56 |
secondary node on them, so they are safe to be rebooted concurrently. |
| 57 |
|
| 58 |
OPTIONS |
| 59 |
------- |
| 60 |
|
| 61 |
For a description of the standard options check **htools**\(7) and |
| 62 |
**hbal**\(1). |
| 63 |
|
| 64 |
\--node-tags *tag,...* |
| 65 |
Restrict to nodes having at least one of the given tags. |
| 66 |
|
| 67 |
\--force |
| 68 |
Do not fail, even if the master node cannot be determined. |
| 69 |
|
| 70 |
|
| 71 |
BUGS |
| 72 |
---- |
| 73 |
|
| 74 |
Offline nodes should be ignored. |
| 75 |
|
| 76 |
If instances are online the tool should refuse to do offline rolling |
| 77 |
maintenances, unless explicitly requested. |
| 78 |
|
| 79 |
End-to-end shelltests should be provided. |
| 80 |
|
| 81 |
Online rolling maintenances (where instance need not be shut down, but |
| 82 |
are migrated from node to node) are not supported yet. Hroller by design |
| 83 |
should support them both with and without secondary node replacement. |
| 84 |
|
| 85 |
EXAMPLE |
| 86 |
------- |
| 87 |
|
| 88 |
Offline Rolling node reboot output |
| 89 |
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| 90 |
|
| 91 |
With the default options, the program shows one reboot group per line as |
| 92 |
a comma-separated list. |
| 93 |
:: |
| 94 |
|
| 95 |
$ hroller -L |
| 96 |
'Node Reboot Groups' |
| 97 |
node1.example.com,node3.example.com,node5.example.com |
| 98 |
node8.example.com,node6.example.com,node2.example.com |
| 99 |
node7.example.com,node4.example.com |
| 100 |
|
| 101 |
.. vim: set textwidth=72 : |
| 102 |
.. Local Variables: |
| 103 |
.. mode: rst |
| 104 |
.. fill-column: 72 |
| 105 |
.. End: |