Every component of Ceph, whether it's MON, OSD, MDS, or RGW, runs as a service on top of an underlying operating system. As a Ceph storage administrator, you should know about the Ceph services and how to operate them. As per Red Hat based distributions, Ceph daemons are managed as a traditional systemd manager service. Each time you start, restart, and stop Ceph daemons (or your entire cluster), you must specify at least one option and one command. You may also specify a daemon type or a daemon instance. The general syntax for this is as follows:
systemctl [options...] command [service name...]
The systemctl options include:
- --help or -h: Prints a short help text
- --all or -a: When listing units, show all loaded units, regardless of their state
- --signal or -s: When used will kill, choose which signal to send to the selected process
- ...