1 HROLLER(1) Ganeti | Version @GANETI_VERSION@
2 ============================================
7 hroller \- Cluster rolling maintenance scheduler for Ganeti
12 **hroller** {backend options...} [algorithm options...] [reporting options...]
14 **hroller** \--version
19 { **-m** *cluster* | **-L[** *path* **]** | **-t** *data-file* |
30 **[ --node-tags** *tag,..* **]**
36 **[ --one-step-only ]**
41 hroller is a cluster maintenance reboot scheduler. It can calculate
42 which set of nodes can be rebooted at the same time while avoiding
43 having both primary and secondary nodes being rebooted at the same time.
45 For backends that support identifying the master node (currenlty
46 RAPI and LUXI), the master node is scheduled as the last node
47 in the last reboot group. Apart from this restriction, larger reboot
50 ALGORITHM FOR CALCULATING OFFLINE REBOOT GROUPS
51 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
53 hroller will view the nodes as vertices of an undirected graph,
54 connecting by instances which have both a primary and a secondary node.
55 It will then color the graph using a few different heuristics, and
56 return the minimum-size color set found. Node with the same color don't
57 share an edge, and as such don't have an instance with both primary and
58 secondary node on them, so they are safe to be rebooted concurrently.
63 For a description of the standard options check **htools**\(7) and
66 \--node-tags *tag,...*
67 Restrict to nodes having at least one of the given tags.
70 Restrict to the first reboot group. Output the group one node per line.
73 Do not fail, even if the master node cannot be determined.
79 Offline nodes should be ignored.
81 If instances are online the tool should refuse to do offline rolling
82 maintenances, unless explicitly requested.
84 End-to-end shelltests should be provided.
86 Online rolling maintenances (where instance need not be shut down, but
87 are migrated from node to node) are not supported yet. Hroller by design
88 should support them both with and without secondary node replacement.
93 Offline Rolling node reboot output
94 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
96 With the default options, the program shows one reboot group per line as
97 a comma-separated list.
102 node1.example.com,node3.example.com,node5.example.com
103 node8.example.com,node6.example.com,node2.example.com
104 node7.example.com,node4.example.com
106 .. vim: set textwidth=72 :