Prepare a configuration file for YDB:

1. Download a sample config for the appropriate failure model of your cluster:

   • block-4-2: For a single-data center cluster.
   • mirror-3dc: For a cross-data center cluster consisting of 9 nodes.
   • mirror-3dc-3nodes: For a cross-data center cluster consisting of 3 nodes.

2. In the host_configs section, specify all disks and their types on each cluster node. Possible disk types:

   • ROT: Rotational, HDD.
   • SSD: SSD or NVMe.

   host_configs:
   - drive:
     - path: /dev/disk/by-partlabel/ydb_disk_ssd_01
       type: SSD
     host_config_id: 1
   

3. In the hosts section, specify the FQDN of each node, their configuration and location in a data_center or rack:

   hosts:
   - host: node1.ydb.tech
     host_config_id: 1
     walle_location:
       body: 1
       data_center: 'zone-a'
       rack: '1'
   - host: node2.ydb.tech
     host_config_id: 1
     walle_location:
       body: 2
       data_center: 'zone-b'
       rack: '1'
   - host: node3.ydb.tech
     host_config_id: 1
     walle_location:
       body: 3
       data_center: 'zone-c'
       rack: '1'
   

4. Under blob_storage_config, edit the FQDNs of all the nodes accommodating your static storage group:

   • For the mirror-3-dc scheme, specify FQDNs for nine nodes.
   • For the block-4-2 scheme, specify FQDNs for eight nodes.

5. Enable user authentication (optional).

   If you plan to use authentication and user access differentiation features in the YDB cluster, add the following parameters to the domains_config section:

   domains_config:
     security_config:
       enforce_user_token_requirement: true
       monitoring_allowed_sids:
       - "root"
       - "ADMINS"
       - "DATABASE-ADMINS"
       administration_allowed_sids:
       - "root"
       - "ADMINS"
       - "DATABASE-ADMINS"
       viewer_allowed_sids:
       - "root"
       - "ADMINS"
       - "DATABASE-ADMINS"