Errors like this appear when you start elasticsearch in a container:
$ journalctl -xe
Dec 27 16:50:17 elasticsearch-03 mount[62]: mount: /sys/kernel/config: cannot mount configfs read-only.
Dec 27 16:50:17 elasticsearch-03 systemd-sysctl[63]: Couldn't write '262144' to 'vm/max_map_count', ignoring: Read-only file system
Dec 27 16:50:17 elasticsearch-03 systemd-sysctl[63]: Couldn't write '1' to 'fs/protected_hardlinks', ignoring: Read-only file system
Dec 27 16:50:17 elasticsearch-03 systemd-sysctl[63]: Couldn't write '1' to 'fs/protected_symlinks', ignoring: Read-only file system
$ /etc/init.d/elasticsearch status