Ceph

# ceph --version
ceph version 0.93 (bebf8e9a830d998eeaab55f86bb256d4360dd3c4)

# crushtool --outfn testmap --build --num_osds 1 host straw2 1 default straw2 0
2015-03-04 12:23:32.198491 7ff0ae3c37c0  1
ID      WEIGHT  TYPE NAME
-2      1.00000 default default
-1      0               host host0
0       0                       osd.0

# crushtool -d testmap -o testmap.txt

# cat testmap.txt
# begin crush map
tunable choose_local_tries 0
tunable choose_local_fallback_tries 0
tunable choose_total_tries 50
tunable chooseleaf_descend_once 1
tunable straw_calc_version 1

# devices
device 0 device0

# types
type 0 device
type 1 host
type 2 default

# buckets
host host0 {
        id -1           # do not change unnecessarily
        # weight 1.000
        alg straw2
        hash 0  # rjenkins1
        item device0 weight 0.000
}
default default {
        id -2           # do not change unnecessarily
        # weight 1.000
        alg straw2
        hash 0  # rjenkins1
        item host0 weight 0.000
}

# rules
rule replicated_ruleset {
        ruleset 0
        type replicated
        min_size 1
        max_size 10
        step take default
        step chooseleaf firstn 0 type host
        step emit
}

# crushtool -c testmap.txt -o testmap.compiled
testmap.txt:16 error: parse error at '# buckets'