Enabling additional service instances¶
To ensure a base level of resiliency, MicroCeph will always try to enable a sufficient number of instances for certain services in the cluster. This number is set to three by default.
The services affected by this include:
Cluster designs that call for extra service instances, however, can be satisfied by manual means. In addition to the above-listed services, the following service can be added manually to a node:
RGW (RADOS Gateway service)
This is the purpose of the enable command. It manually enables a new instance of a service on a node.
The syntax is:
sudo microceph enable <service> --target <destination> ...
Where the service value is one of ‘mon’, ‘mds’, ‘mgr’, and ‘rgw’. The destination is a node name as discerned by the output of the status command:
sudo microceph status
For a given service, the enable command may support extra parameters. These can be discovered by querying for help for the respective service:
sudo microceph enable <service> --help
Example: enable an RGW service¶
First check the status of the cluster to get node names and an overview of existing services:
sudo microceph status MicroCeph deployment summary: - node1-2c3eb41e-14e8-465d-9877-df36f5d80922 (10.111.153.78) Services: mds, mgr, mon, osd Disks: 3 - workbook (192.168.29.152) Services: mds, mgr, mon Disks: 0
View any possible extra parameters for the RGW service:
sudo microceph enable rgw --help
To enable the RGW service on node1 and specify a value for extra parameter port:
sudo microceph enable rgw --target node1 --port 8080
Finally, view cluster status again and verify expected changes:
sudo microceph status MicroCeph deployment summary: - node1 (10.111.153.78) Services: mds, mgr, mon, rgw, osd Disks: 3 - workbook (192.168.29.152) Services: mds, mgr, mon Disks: 0