Unhandled exception from module 'dashboard' while running on mgr.hosts

Bug Report

What happened:

2018-12-17 11:39:43.120050 [ERR]  Unhandled exception from module 'dashboard' while running on mgr.k8store01: IOError("Port 9000 not bound on '::'",)
2018-12-17 11:23:04.636503 [ERR]  Unhandled exception from module 'dashboard' while running on mgr.k8store03: IOError("Port 9000 not bound on '::'",)
2018-12-17 11:22:14.467886 [INF]  Manager daemon k8store03 is now available
2018-12-17 11:22:14.313213 [INF]  Active manager daemon k8store03 restarted

What you expected to happen:

How to reproduce it (minimal and precise):

Share your group_vars files, inventory

$ egrep -v "^#|^$" group_vars/all.yml
---
dummy:
ceph_origin: repository
ceph_repository: community
ceph_mirror: https://mirrors.aliyun.com/ceph
ceph_stable_key: https://mirrors.aliyun.com/ceph/keys/release.asc
ceph_stable_release: luminous
ceph_stable_repo: "{{ ceph_mirror }}/rpm-{{ ceph_stable_release }}"
fsid: 17ffc828-5d8c-4937-a5bb-f6adb2384d20
generate_fsid: true
ceph_conf_key_directory: /etc/ceph
cephx: true
monitor_interface: bond0
public_network: 172.17.0.0/16
cluster_network: 172.17.0.0/16
ceph_conf_overrides:
  global:
    rbd_default_features: 7
    auth cluster required: cephx
    auth service required: cephx
    auth client required: cephx
    osd journal size: 2048
    osd pool default size: 3
    osd pool default min size: 1
    mon_pg_warn_max_per_osd: 1024
    osd pool default pg num: 1024
    osd pool default pgp num: 1024
    max open files: 131072
    osd_deep_scrub_randomize_ratio: 0.01
  mon:
    mon_allow_pool_delete: true
  client:
    rbd_cache: true
    rbd_cache_size: 335544320
    rbd_cache_max_dirty: 134217728
    rbd_cache_max_dirty_age: 10
  mgr:
    mgr modules: dashboard
  osd:
    osd mkfs type: xfs
    ms_bind_port_max: 7100
    osd_client_message_size_cap: 2147483648
    osd_crush_update_on_start: true
    osd_deep_scrub_stride: 131072
    osd_disk_threads: 4
    osd_map_cache_bl_size: 128
    osd_max_object_name_len: 256
    osd_max_object_namespace_len: 64
    osd_max_write_size: 1024
    osd_op_threads: 8
    osd_recovery_op_priority: 1
    osd_recovery_max_active: 1
    osd_recovery_max_single_start: 1
    osd_recovery_max_chunk: 1048576
    osd_recovery_threads: 1
    osd_max_backfills: 4
    osd_scrub_begin_hour: 23
    osd_scrub_end_ho

$ egrep -v "^#|^$" group_vars/osds.yml
---
dummy:
devices:
  - /dev/sdb
  - /dev/sdc
  - /dev/sdd
  - /dev/sde
  - /dev/sdf
  - /dev/sdg
osd_scenario: collocated
osd_objectstore: bluestoreur: 7

$ egrep -v "^#|^$" site.yml
---
- hosts:
  - mons
  - osds
  - mdss
  - clients
  - mgrs

No changes have been made to the other documents.

Environment:

OS (e.g. from /etc/os-release):

$ cat /etc/redhat-release
CentOS Linux release 7.2.1511 (Core)

Kernel (e.g. uname -a):

$ uname -a
Linux k8store02.ops.bj2.yongche.com 3.10.0-327.el7.x86_64 #1 SMP Thu Nov 19 22:10:57 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

Docker version if applicable (e.g. docker version): Non-docker deployment

Ansible version (e.g. ansible-playbook --version):

$ ansible-playbook --version
ansible-playbook 2.6.5
config file = /home/yangsheng/ceph-ansible-3.2.0/ansible.cfg
configured module search path = [u'/root/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
ansible python module location = /usr/lib/python2.7/site-packages/ansible
executable location = /bin/ansible-playbook
python version = 2.7.5 (default, Oct 30 2018, 23:45:53) [GCC 4.8.5 20150623 (Red Hat 4.8.5-36)]

ceph-ansible version (e.g. git head or tag or stable branch):
```
ceph-ansible-3.2.0
```

Ceph version (e.g. ceph -v):

$ ceph -v
ceph version 12.2.10 (177915764b752804194937482a39e95e0ca3de94) luminous (stable)

ceph / ceph-ansible

Unhandled exception from module 'dashboard' while running on mgr.hosts #3449