Ceph » mgr

Problem:
When using the ceph-mgr balancer in 13.2.1 (and 12.2.5 previously), trying to create an optimized plan results in the ceph-mgr hanging.

I'm using the upmap mode for the balancer:

1. ceph balancer status {
   "active": false,
   "plans": [],
   "mode": "upmap"
   }

Log messages look like this:
2018-07-30 15:45:14.979 7fe096cca700 1 mgr[balancer] Handling command: '{'prefix': 'balancer optimize', 'plan': 'run20180730', 'target': [
'mgr', '']}'
2018-07-30 15:45:15.063 7fe096cca700 4 mgr[balancer] Optimize plan run20180730
2018-07-30 15:45:15.063 7fe096cca700 4 mgr get_config get_config key: mgr/balancer/mode
2018-07-30 15:45:15.063 7fe096cca700 4 mgr get_config get_config key: mgr/balancer/max_misplaced
2018-07-30 15:45:15.063 7fe096cca700 4 mgr[balancer] Mode upmap, max misplaced 0.010000
2018-07-30 15:45:15.063 7fe096cca700 4 mgr[balancer] do_upmap
2018-07-30 15:45:15.063 7fe096cca700 4 mgr get_config get_config key: mgr/balancer/upmap_max_iterations
2018-07-30 15:45:15.063 7fe096cca700 4 ceph_config_get upmap_max_iterations not found
2018-07-30 15:45:15.067 7fe096cca700 4 mgr get_config get_config key: mgr/balancer/upmap_max_deviation
2018-07-30 15:45:15.067 7fe096cca700 4 ceph_config_get upmap_max_deviation not found
2018-07-30 15:45:15.067 7fe096cca700 4 mgr[balancer] pools ['rbd', 'cephfs_data_ec42', 'cephfs_data', 'cephfs_metadata']

Nothing else related to balancing is seen after that.

Expected result:
Another pass is done by the balancer to bring the cluster a step closer to being balanced.

Additional notes:
Trying to manually optimize the cluster results in a segfault:

1. ceph osd getmap -o osdmap-20180730.bin
   got osdmap epoch 101015
2. osdmaptool osdmap-20180730.bin --upmap upmaps-20180730.txt
   osdmaptool: osdmap file 'osdmap-20180730.bin'
   writing upmap command output to: upmaps-20180730.txt
   checking for upmap cleanups
   upmap, max-count 100, max deviation 0.01
   • Caught signal (Segmentation fault) **
     in thread 7fe69b6da8c0 thread_name:osdmaptool
     Segmentation fault (core dumped)