Adding CRUSH rules

Use this information to add CRUSH rules from the command-line.

To add a CRUSH rule, you must specify a rule name, the root node of the hierarchy you wish to use, the type of bucket you want to replicate across (for example, rack, row, and so on and the mode for choosing the bucket.

Syntax

ceph osd crush rule create-simple RUENAME ROOT BUCKET_NAME FIRSTN_OR_INDEP

Ceph creates a rule with chooseleaf and one bucket of the type you specify.

Example

[ceph: root@host01 /]# ceph osd crush rule create-simple deleteme default host firstn

Create the following rule:

{ "id": 1,
  "rule_name": "deleteme",
  "type": 1,
  "min_size": 1,
  "max_size": 10,
  "steps": [
        { "op": "take",
          "item": -1,
          "item_name": "default"},
        { "op": "chooseleaf_firstn",
          "num": 0,
          "type": "host"},
        { "op": "emit"}]}