Deploy Database Cluster

Recommended Process

When deploying a database cluster, it is recommended that you follow the process below:

1. Prepare the configuration file that describes the cluster.
2. Perform operation system check to ensure that the operating system does not have unusual check items before installation.
3. Download the required database installation package from the official website.
4. Deploy the database cluster.

Database Cluster Installation

Instruction

Since all PTK behaviors are based on SSH connections for issuing commands, we need to configure the ssh_option field for each database server in the configuration file. Of course, if all servers have the same connection user, port, and password, you only need to configure ssh_option once in the global section.

For the login user in ssh_option, we recommend that you configure the root user or a user with sudo privileges. Since the database as a basic software may have more stringent requirements than other applications, you need to use the superuser privilege to set a more permissive ulimit configuration for the system user running the database. At the same time, if you provide super user, you don't need to create the operating system user to run the database in advance, you only need to define the user name in the configuration file, and PTK will automatically create the corresponding user for you and set up the ulimit configuration.

Of course, if you are under the mandatory requirements of enterprise security, you may not be able to meet the conditions of direct login of root user, but you can also use PTK for deployment. In this case, you need to do the following 3 steps in advance:

1. Create the operating system user on the server that will be used to run the database (assuming the user name is omm).

2. Add the following configuration entry for this user at the end of the /etc/security/limits.conf file (replace omm with the username you created):

   omm     soft    as      unlimited
   omm     hard    as      unlimited
   omm     soft    nproc   unlimited
   omm     hard    nproc   unlimited
   omm     soft    nofile  1000000
   omm     hard    nofile  1000000
   omm     soft    stack   unlimited
   omm     hard    stack   unlimited

3. Change the SSH login user to omm in the ssh_option section of the configuration file.

   ssh_option:
   user: omm
   ...

Note: If you use a non-superuser for cluster management, some commands that rely on superprivileges will not be available later, such as install-mogha.

Online Installation

Installation is accomplished with a single line of command:

ptk install -f config.yaml

This command automatically downloads the latest LTS version of MogDB from the network and installs it. If you wish to specify the version of MogDB yourself, you can do so with the --db-version option, for example:

ptk install -f config.yaml --db-version 5.0.7

You can use ptk candidate db to see the list of MogDB versions that PTK supports to download automatically.

PTK will launch the database cluster by default after installing the database cluster. If you do not want the cluster to be launched automatically after installation, you can specify the -skip-launch-db option in the command line.

Offline Installation

If you have downloaded the installer in advance, you can specify a local installer for offline installation with the -p option:

ptk install -f config.yaml -p <package>

Deploy CM Cluster Together

PTK supports deploying the CM cluster at the same time as the database cluster, you just need to add an --install-cm option to the install command:

Minimum of 2 nodes for the cluster to take effect.

ptk install -f config.yaml --install-cm

By default, PTK deploys the CM server and database instances together to match the number of databases. If the number of clusters is greater than 3, we recommend deploying an odd number of CM server nodes by default due to the majority election algorithm for CM High Availability, so when deploying an even number of database instances, PTK will interactively allow you to select a node to not deploy CM server. You can remove this restriction by adding the --not-limit-cm-nodes option to the install command if you still want the number of CM server and database instances to be consistent.

Deploy In Resource Pooling Mode（beta）

Although the kernel resource pooling feature is still under deep development, PTK has gradually supported resource pooling deployment since version 1.2.0. Resource pooling deployment provides the ability for primary and standby nodes to share storage, realizes resource pooling HA deployment form based on magnetic array devices, solves the problem of doubling the storage capacity of a single machine under traditional HA deployment, and at the same time, the standby nodes support real-time consistency of reads.

The resource pooling architecture diagram is shown below.

PTK supports deployment in resource pooling scenarios. Since the DSS module has been added to the resource pooling architecture and relies on CM for high availability management of clusters, we need to add the dss_option and cm_option sections to the configuration file, as shown in the following example configuration.

global:
    cluster_name: c1
    user: omm
    db_password: pTk6Y2I1OWFiZjI8RT1FPUE9RFZfVTUzTy0zUlR5TDZUTmh1STE4VkQ0T2RDYXBNMThoSlNhZDY3UHB4WVE=
    db_port: 26000
    base_dir: /data/mogdb
    ssh_option:
        port: 22
        user: root
        password: pTk6ZDJmZjZlZjI8RT1FPUE9RUs4WEh1OUJRQURfM29GUjZyb3gzZGU3LVRmLTM3Mm5ySmZ5anJXVkNOTUE=
    cm_option:
        dir: /data/mogdb/cm
        cm_server_port: 15300
    dss_option:
        dir: /data/mogdb/dss
        dss_port: 26010
        dms_port: 26020
        data_vg_name: data
        data_vg_path: /dev/data_shared
        inst_vg_map:
          172.23.1.28: /dev/data_private_28
          172.23.1.45: /dev/data_private_45
        cm_share_vg_path: /dev/cm_shared
        cm_voting_vg_path: /dev/cm_vote
        enable_ssl: on
db_servers:
    - host: 172.23.1.28
      role: primary
    - host: 172.23.1.45
      role: standby

The rest of the configuration is the same as a normal installation, we focus on the dss_option section.

In the dss_option section, there are the following fields:

Once you have prepared the configuration file, simply add the --enable-dss option to the install command:

ptk install -f config.yaml --enable-dss

More Parameters

The above documentation gives some examples of parameter combinations for different usage scenarios, PTK's install command supports many more parameters, you can check Commands for more information.

Installation Result Status