docker redis container startup issue - docker

Question

I have question about docker redis-sentinel:5.0.10 startup issue.
I am running docker on CentOS7 Linux.
Before 5.0.10 version I used 4.0.9 and image was taken from our own repository, now I switched to bitnami repo.
The main problem is that I try to use redis-sentinel:5.0.10 (or redis-sentinel:5.0.7) and it falls into restart loop and cannot start properly.
I run containers like that:
[root#XXX opt]# docker run -d -p 26380:26379 -v /opt/app/redis:/data --name redis-sentinel -e REDIS_MASTER_HOST=XXX.XXX.XXX -e REDIS_MASTER_SET=XXX-XXX -e REDIS_SENTINEL_DOWN_AFTER_MILLISECONDS=30000 -e REDIS_SENTINEL_QUORUM=2 -e REDIS_SENTINEL_FAILOVER_TIMEOUT=180000 --net=host --restart=always bitnami/redis-sentinel:5.0.10
[root#XXX opt]# docker run -d --net=host -v /opt/app/redis:/data -v /opt/app/redis.conf:/usr/local/etc/redis/redis.conf --name redis-client --restart=always redis:5.0.10-alpine redis-server --slaveof XXX.XXX.XXX 6379
In log there are messages like:
redis-sentinel 10:16:50.45 Welcome to the Bitnami redis-sentinel container
redis-sentinel 10:16:50.45 Subscribe to project updates by watching https://github.com/bitnami/bitnami-docker-redis-sentinel
redis-sentinel 10:16:50.45 Submit issues and feature requests at https://github.com/bitnami/bitnami-docker-redis-sentinel/issues
redis-sentinel 10:16:50.46
redis-sentinel 10:16:50.46 INFO ==> ** Starting Redis sentinel setup **
redis-sentinel 10:16:50.47 ERROR ==> The configuration file /opt/bitnami/redis-sentinel/etc/sentinel.conf is not writable
Why it is not writable?
[root#dam31 ~]# docker run --rm -it bitnami/redis-sentinel:5.0.10 sh
redis-sentinel 14:03:36.16
redis-sentinel 14:03:36.16 Welcome to the Bitnami redis-sentinel container
redis-sentinel 14:03:36.17 Subscribe to project updates by watching https://github.com/bitnami/bitnami-docker-redis-sentinel
redis-sentinel 14:03:36.17 Submit issues and feature requests at https://github.com/bitnami/bitnami-docker-redis-sentinel/issues
redis-sentinel 14:03:36.17
$ cd /opt/bitnami/redis-sentinel/etc/
$ ls -l
total 12
-rw-rw-r-- 1 root root 9797 Dec 8 13:25 sentinel.conf
docker ps command says:
[root#XXX app]# docker ps --no-trunc
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
45988acb45407dfc7a19f4a2a08da7c8f7a99381a97bc17a3ae985d377605462 redis:5.0.10-alpine "docker-entrypoint.sh redis-server --slaveof XXX.XXX.XXX 6379" 4 minutes ago Up 3 minutes redis-client
94b9b8e712e2219bc3f9a18aba349985968e3410c5336905282fb43b38e89e8e bitnami/redis-sentinel:5.0.10 "/opt/bitnami/scripts/redis-sentinel/entrypoint.sh /opt/bitnami/scripts/redis-sentinel/run.sh" 4 minutes ago Restarting (1) 19 seconds ago redis-sentinel
On other machines I have upgraded redis to 5.0.7 version successfully and it runs properly, nothing was done otherwise:
[root#XXX app]# docker ps --no-trunc
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
07e535350c02a67478dd07708a06798981fe7e99ae448567837dacdee198ec1e redis:5.0.7-alpine "docker-entrypoint.sh redis-server /usr/local/etc/redis/redis.conf --slaveof XXX.XXX.XXX 6379" 8 weeks ago Up 8 weeks redis-client
fea1bff3b2c1fbc9c7cea2becad64b7e2727dfc1f73f1d541e08b9b75143b3a9 bitnami/redis-sentinel:5.0.7 "/entrypoint.sh /run.sh" 8 weeks ago Up 8 weeks redis-sentinel
If I run on the same machine (where I tried to run redis:5.0.10) redis:5.0.7 the same error occured:
[root#XXX ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
15cdd46fa325 redis:5.0.7-alpine "docker-entrypoint.s…" 15 minutes ago Up 15 minutes redis-client
b0b02a36b68c bitnami/redis-sentinel:5.0.7 "/entrypoint.sh /run…" 16 minutes ago Restarting (1) 50 seconds ago redis-sentinel
redis-sentinel 14:16:23.86 Welcome to the Bitnami redis-sentinel container
redis-sentinel 14:16:23.87 Subscribe to project updates by watching https://github.com/bitnami/bitnami-docker-redis-sentinel
redis-sentinel 14:16:23.87 Submit issues and feature requests at https://github.com/bitnami/bitnami-docker-redis-sentinel/issues
redis-sentinel 14:16:23.87 Send us your feedback at containers#bitnami.com
redis-sentinel 14:16:23.87
redis-sentinel 14:16:23.87 INFO ==> ** Starting Redis sentinel setup **
redis-sentinel 14:16:23.88 ERROR ==> The configuration file /opt/bitnami/redis-sentinel/etc/sentinel.conf is not writable
What I am doing wrong? Any thoughts? (NB! SELinux is disabled)