Deploying MONs

The Monitor (MON) monitors the status of the Ceph cluster. You only need to perform MON deployment operations on the primary node (ceph1 is used as an example).

1. Create a Ceph cluster. The following uses ceph1, ceph2, and ceph3 as an example.

   1 2	cd /etc/ceph ceph-deploy new ceph1 ceph2 ceph3

   

2. Configure global parameters and MON parameters for the Ceph cluster.
   

   Operations such as configuring nodes and using ceph-deploy to configure OSDs need to be performed in the /etc/ceph directory. Otherwise, an error may occur.

   1. Open the ceph.conf file that is automatically generated in the /etc/ceph directory.

      1	vi /etc/ceph/ceph.conf

   2. Press i to enter the insert mode and change the content in ceph.conf to the following information (use the latest fsid):

      1 2 3 4 5 6 7 8 9 10 11 12 13

      [global] fsid = f5a4f55c-d25b-4339-a1ab-0fceb4a2996f mon_initial_members = ceph1, ceph2, ceph3 mon_host = 192.168.3.166,192.168.3.167,192.168.3.168 auth_cluster_required = cephx auth_service_required = cephx auth_client_required = cephx public_network = 192.168.65.0/24 cluster_network = 192.168.66.0/24 [mon] mon_allow_pool_delete = true

      For a single-node environment, add the following content below [global]:

      1 2	osd_pool_default_size = 1 osd_pool_default_min_size = 1

   3. Press Esc to exit the insert mode. Type :wq! and press Enter to save the file and exit.
   

   In Ceph 14.2.8, when the BlueStore engine is used, the buffer of the BlueFS is enabled by default. As a result, the system memory may be fully occupied by the buffer or cache, causing performance deterioration. You can use either of the following methods to solve the problem:

   • If the cluster load is not heavy, set bluefs_buffered_io to false.
   • Periodically run the following command to forcibly reclaim the memory occupied by the buffer or cache:

     echo 3 > /proc/sys/vm/drop_caches

3. Initialize the monitor and collect keys.

   1	ceph-deploy mon create-initial

   

4. Copy ceph.client.admin.keyring generated after 3 is successfully performed to each node.

   1	ceph-deploy --overwrite-conf admin ceph1 ceph2 ceph3 client1 client2 client3

   

5. Check the Ceph cluster status to determine whether the MONs are successfully configured.

   1

   ceph -s

   Expected result of successful configuration:

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   cluster: id: f6b3c38c-7241-44b3-b433-52e276dd53c6 health: HEALTH_OK services: mon: 3 daemons, quorum ceph1,ceph2,ceph3 (age 25h)

   

   If MONs fails to be generated, the permission configuration may be incorrect. In this case, you need to configure the Ceph group and users.

   /usr/sbin/groupadd ceph -g 167 -o -r 2>/dev/null || :/usr/sbin/useradd ceph -u 167 -o -r -g ceph -s /sbin/nologin -c "Ceph daemons" -d /var/lib/ceph 2>/dev/null || :