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Chapter 2. Management of services using the Ceph Orchestrator
As a storage administrator, after installing the Red Hat Ceph Storage cluster, you can monitor and manage the services in a storage cluster using the Ceph Orchestrator. A service is a group of daemons that are configured together.
This section covers the following administrative information:
- Placement specification of the Ceph Orchestrator.
- Deploying the Ceph daemons using the command line interface.
- Deploying the Ceph daemons on a subset of hosts using the command line interface.
- Service specification of the Ceph Orchestrator.
- Deploying the Ceph daemons using the service specification.
- Deploying the Ceph File System mirroring daemon using the service specification.
2.1. Placement specification of the Ceph Orchestrator
You can use the Ceph Orchestrator to deploy osds
, mons
, mgrs
, mds
, and rgw
services. Red Hat recommends deploying services using placement specifications. You need to know where and how many daemons have to be deployed to deploy a service using the Ceph Orchestrator. Placement specifications can either be passed as command line arguments or as a service specification in a yaml
file.
There are two ways of deploying the services using the placement specification:
Using the placement specification directly in the command line interface. For example, if you want to deploy three monitors on the hosts, running the following command deploys three monitors on
host01
,host02
, andhost03
.Example
[ceph: root@host01 /]# ceph orch apply mon --placement="3 host01 host02 host03"
Using the placement specification in the YAML file. For example, if you want to deploy
node-exporter
on all the hosts, then you can specify the following in theyaml
file.Example
service_type: node-exporter placement: host_pattern: '*' extra_entrypoint_args: - "--collector.textfile.directory=/var/lib/node_exporter/textfile_collector2"
2.2. Deploying the Ceph daemons using the command line interface
Using the Ceph Orchestrator, you can deploy the daemons such as Ceph Manager, Ceph Monitors, Ceph OSDs, monitoring stack, and others using the ceph orch
command. Placement specification is passed as --placement
argument with the Orchestrator commands.
Prerequisites
- A running Red Hat Ceph Storage cluster.
- Hosts are added to the storage cluster.
Procedure
Log into the Cephadm shell:
Example
[root@host01 ~]# cephadm shell
Use one of the following methods to deploy the daemons on the hosts:
Method 1: Specify the number of daemons and the host names:
Syntax
ceph orch apply SERVICE_NAME --placement="NUMBER_OF_DAEMONS HOST_NAME_1 HOST_NAME_2 HOST_NAME_3"
Example
[ceph: root@host01 /]# ceph orch apply mon --placement="3 host01 host02 host03"
Method 2: Add the labels to the hosts and then deploy the daemons using the labels:
Add the labels to the hosts:
Syntax
ceph orch host label add HOSTNAME_1 LABEL
Example
[ceph: root@host01 /]# ceph orch host label add host01 mon
Deploy the daemons with labels:
Syntax
ceph orch apply DAEMON_NAME label:LABEL
Example
ceph orch apply mon label:mon
Method 3: Add the labels to the hosts and deploy using the
--placement
argument:Add the labels to the hosts:
Syntax
ceph orch host label add HOSTNAME_1 LABEL
Example
[ceph: root@host01 /]# ceph orch host label add host01 mon
Deploy the daemons using the label placement specification:
Syntax
ceph orch apply DAEMON_NAME --placement="label:LABEL"
Example
ceph orch apply mon --placement="label:mon"
Verification
List the service:
Example
[ceph: root@host01 /]# ceph orch ls
List the hosts, daemons, and processes:
Syntax
ceph orch ps --daemon_type=DAEMON_NAME ceph orch ps --service_name=SERVICE_NAME
Example
[ceph: root@host01 /]# ceph orch ps --daemon_type=mon [ceph: root@host01 /]# ceph orch ps --service_name=mon
Additional Resources
- See the Adding hosts using the Ceph Orchestrator section in the Red Hat Ceph Storage Operations Guide.
2.3. Deploying the Ceph daemons on a subset of hosts using the command line interface
You can use the --placement
option to deploy daemons on a subset of hosts. You can specify the number of daemons in the placement specification with the name of the hosts to deploy the daemons.
Prerequisites
- A running Red Hat Ceph Storage cluster.
- Hosts are added to the cluster.
Procedure
Log into the Cephadm shell:
Example
[root@host01 ~]# cephadm shell
List the hosts on which you want to deploy the Ceph daemons:
Example
[ceph: root@host01 /]# ceph orch host ls
Deploy the daemons:
Syntax
ceph orch apply SERVICE_NAME --placement="NUMBER_OF_DAEMONS HOST_NAME_1 _HOST_NAME_2 HOST_NAME_3"
Example
ceph orch apply mgr --placement="2 host01 host02 host03"
In this example, the
mgr
daemons are deployed only on two hosts.
Verification
List the hosts:
Example
[ceph: root@host01 /]# ceph orch host ls
Additional Resources
- See the Listing hosts using the Ceph Orchestrator section in the Red Hat Ceph Storage Operations Guide.
2.4. Service specification of the Ceph Orchestrator
A service specification is a data structure to specify the service attributes and configuration settings that is used to deploy the Ceph service. The following is an example of the multi-document YAML file, cluster.yaml
, for specifying service specifications:
Example
service_type: mon placement: host_pattern: "mon*" --- service_type: mgr placement: host_pattern: "mgr*" --- service_type: osd service_id: default_drive_group placement: host_pattern: "osd*" data_devices: all: true
The following list are the parameters where the properties of a service specification are defined as follows:
service_type
: The type of service:- Ceph services like mon, crash, mds, mgr, osd, rbd, or rbd-mirror.
- Ceph gateway like nfs or rgw.
- Monitoring stack like Alertmanager, Prometheus, Grafana or Node-exporter.
- Container for custom containers.
-
service_id
: A unique name of the service. -
placement
: This is used to define where and how to deploy the daemons. -
unmanaged
: If set totrue
, the Orchestrator will neither deploy nor remove any daemon associated with this service.
Stateless service of Orchestrators
A stateless service is a service that does not need information of the state to be available. For example, to start an rgw
service, additional information is not needed to start or run the service. The rgw
service does not create information about this state in order to provide the functionality. Regardless of when the rgw
service starts, the state is the same.
2.5. Disabling automatic management of daemons
You can mark the Cephadm services as managed
or unmanaged
without having to edit and re-apply the service specification.
Prerequisites
- A running Red Hat Ceph Storage cluster.
- Root-level access to all the nodes.
Procedure
Set
unmanaged
for services by using this command:Syntax
ceph orch set-unmanaged SERVICE_NAME
Example
[root@host01 ~]# ceph orch set-unmanaged grafana
Set
managed
for services by using this command:Syntax
ceph orch set-managed SERVICE_NAME
Example
[root@host01 ~]# ceph orch set-managed mon
2.6. Deploying the Ceph daemons using the service specification
Using the Ceph Orchestrator, you can deploy daemons such as ceph Manager, Ceph Monitors, Ceph OSDs, monitoring stack, and others using the service specification in a YAML file.
Prerequisites
- A running Red Hat Ceph Storage cluster.
- Root-level access to all the nodes.
Procedure
Create the
yaml
file:Example
[root@host01 ~]# touch mon.yaml
This file can be configured in two different ways:
Edit the file to include the host details in placement specification:
Syntax
service_type: SERVICE_NAME placement: hosts: - HOST_NAME_1 - HOST_NAME_2
Example
service_type: mon placement: hosts: - host01 - host02 - host03
Edit the file to include the label details in placement specification:
Syntax
service_type: SERVICE_NAME placement: label: "LABEL_1"
Example
service_type: mon placement: label: "mon"
Optional: You can also use extra container arguments in the service specification files such as CPUs, CA certificates, and other files while deploying services:
Example
extra_container_args: - "-v" - "/etc/pki/ca-trust/extracted:/etc/pki/ca-trust/extracted:ro" - "--security-opt" - "label=disable" - "cpus=2" - "--collector.textfile.directory=/var/lib/node_exporter/textfile_collector2"
NoteRed Hat Ceph Storage supports the use of extra arguments to enable additional metrics in node-exporter deployed by Cephadm.
Mount the YAML file under a directory in the container:
Example
[root@host01 ~]# cephadm shell --mount mon.yaml:/var/lib/ceph/mon/mon.yaml
Navigate to the directory:
Example
[ceph: root@host01 /]# cd /var/lib/ceph/mon/
Deploy the Ceph daemons using service specification:
Syntax
ceph orch apply -i FILE_NAME.yaml
Example
[ceph: root@host01 mon]# ceph orch apply -i mon.yaml
Verification
List the service:
Example
[ceph: root@host01 /]# ceph orch ls
List the hosts, daemons, and processes:
Syntax
ceph orch ps --daemon_type=DAEMON_NAME
Example
[ceph: root@host01 /]# ceph orch ps --daemon_type=mon
Additional Resources
- See the Listing hosts using the Ceph Orchestrator section in the Red Hat Ceph Storage Operations Guide.
2.7. Deploying the Ceph File System mirroring daemon using the service specification
Ceph File System (CephFS) supports asynchronous replication of snapshots to a remote CephFS file system using the CephFS mirroring daemon (cephfs-mirror
). Snapshot synchronization copies snapshot data to a remote CephFS, and creates a new snapshot on the remote target with the same name. Using the Ceph Orchestrator, you can deploy cephfs-mirror
using the service specification in a YAML file.
Prerequisites
- A running Red Hat Ceph Storage cluster.
- Root-level access to all the nodes.
- A CephFS created.
Procedure
Create the
yaml
file:Example
[root@host01 ~]# touch mirror.yaml
Edit the file to include the following:
Syntax
service_type: cephfs-mirror service_name: SERVICE_NAME placement: hosts: - HOST_NAME_1 - HOST_NAME_2 - HOST_NAME_3
Example
service_type: cephfs-mirror service_name: cephfs-mirror placement: hosts: - host01 - host02 - host03
Mount the YAML file under a directory in the container:
Example
[root@host01 ~]# cephadm shell --mount mirror.yaml:/var/lib/ceph/mirror.yaml
Navigate to the directory:
Example
[ceph: root@host01 /]# cd /var/lib/ceph/
Deploy the
cephfs-mirror
daemon using the service specification:Example
[ceph: root@host01 /]# ceph orch apply -i mirror.yaml
Verification
List the service:
Example
[ceph: root@host01 /]# ceph orch ls
List the hosts, daemons, and processes:
Example
[ceph: root@host01 /]# ceph orch ps --daemon_type=cephfs-mirror
Additional Resources
-
See Ceph File System mirrors for more information about the
cephfs-mirror
daemon.