Gitlab-shell Redis Sentinel No sentinels available

I tried to configure gitlab-shell with redis sentinel. I tried several times, but all failed. Is there anybody who has encountered a similar problem?

git@05e501a59f95:~/gitlab-shell/bin$ ./check 
Check GitLab API access: OK
Access to /home/git/.ssh/authorized_keys: OK
Send ping to redis server: /home/git/gitlab-shell/lib/vendor/redis/lib/redis/client.rb:567:in 'sentinel_detect': No sentinels available. (Redis::CannotConnectError)
	from /home/git/gitlab-shell/lib/vendor/redis/lib/redis/client.rb:571:in 'resolve_master'
	from /home/git/gitlab-shell/lib/vendor/redis/lib/redis/client.rb:535:in 'resolve'
	from /home/git/gitlab-shell/lib/vendor/redis/lib/redis/client.rb:331:in 'establish_connection'
	from /home/git/gitlab-shell/lib/vendor/redis/lib/redis/client.rb:101:in 'block in connect'
	from /home/git/gitlab-shell/lib/vendor/redis/lib/redis/client.rb:293:in 'with_reconnect'
	from /home/git/gitlab-shell/lib/vendor/redis/lib/redis/client.rb:100:in 'connect'
	from /home/git/gitlab-shell/lib/vendor/redis/lib/redis/client.rb:364:in 'ensure_connected'
	from /home/git/gitlab-shell/lib/vendor/redis/lib/redis/client.rb:221:in 'block in process'
	from /home/git/gitlab-shell/lib/vendor/redis/lib/redis/client.rb:306:in 'logging'
	from /home/git/gitlab-shell/lib/vendor/redis/lib/redis/client.rb:220:in 'process'
	from /home/git/gitlab-shell/lib/vendor/redis/lib/redis/client.rb:120:in 'call'
	from /home/git/gitlab-shell/lib/vendor/redis/lib/redis.rb:149:in 'block in ping'
	from /home/git/gitlab-shell/lib/vendor/redis/lib/redis.rb:58:in 'block in synchronize'
	from /usr/local/lib/ruby/2.3.0/monitor.rb:214:in 'mon_synchronize'
	from /home/git/gitlab-shell/lib/vendor/redis/lib/redis.rb:58:in 'synchronize'
	from /home/git/gitlab-shell/lib/vendor/redis/lib/redis.rb:148:in 'ping'
	from ./check:35:in '<main>'

and my config.yml is

---
user: git
gitlab_url: http://localhost/
http_settings:
  self_signed_cert: false
auth_file: "/home/git/.ssh/authorized_keys"
redis:
  bin: "/usr/bin/redis-cli"
  namespace: resque:gitlab
  #socket: "/var/run/redis/redis.sock"
  #host: redis1
  #port: 6379
  sentinels:
    -
      host: redis-sentinel1
      port: 26379
    -
      host: redis-sentinel2
      port: 26379
    -
      host: redis-sentinel3
      port: 26379

log_level: INFO
audit_usernames: false

and my redis-sentinel info is

git@05e501a59f95:~/gitlab-shell$ redis-cli -h redis-sentinel1 -p 26379
redis-sentinel1:26379> info
# Server
redis_version:3.2.8
redis_git_sha1:00000000
redis_git_dirty:0
redis_build_id:36c619aa94c6572b
redis_mode:sentinel
os:Linux 3.10.0-514.10.2.el7.x86_64 x86_64
arch_bits:64
multiplexing_api:epoll
gcc_version:4.9.2
process_id:1
run_id:b887a0ddcdd9dab5606b8e2c880d20056e409b39
tcp_port:26379
uptime_in_seconds:7721
uptime_in_days:0
hz:12
lru_clock:14631462
executable:/data/redis-sentinel
config_file:/usr/local/etc/redis/sentinel.conf

# Clients
connected_clients:3
client_longest_output_list:0
client_biggest_input_buf:0
blocked_clients:0

# CPU
used_cpu_sys:6.95
used_cpu_user:3.95
used_cpu_sys_children:0.00
used_cpu_user_children:0.00

# Stats
total_connections_received:36
total_commands_processed:22366
instantaneous_ops_per_sec:1
total_net_input_bytes:1234727
total_net_output_bytes:134892
instantaneous_input_kbps:0.02
instantaneous_output_kbps:0.01
rejected_connections:0
sync_full:0
sync_partial_ok:0
sync_partial_err:0
expired_keys:0
evicted_keys:0
keyspace_hits:0
keyspace_misses:0
pubsub_channels:0
pubsub_patterns:0
latest_fork_usec:0
migrate_cached_sockets:0

# Sentinel
sentinel_masters:1
sentinel_tilt:0
sentinel_running_scripts:0
sentinel_scripts_queue_length:0
sentinel_simulate_failure_flags:0
master0:name=mymaster,status=ok,address=192.168.6.3:6379,slaves=2,sentinels=3

Who can tell me where the problem is?

My gitlab-ce version is 8.17.4