Preparing the inventory file

Installation, update, and removal of KUMA components is performed from the folder containing the unpacked installer by using the Ansible tool and the user-created inventory file containing a list of the hosts of KUMA components and other parameters. The inventory file is in the YAML format.

To create an inventory file:

1. Go to the KUMA installer folder by executing the following command:

   cd kuma-ansible-installer

2. Create an inventory file by copying the distributed.inventory.yml.template:

   cp distributed.inventory.yml.template distributed.inventory.yml

3. Edit the inventory file parameters:
   • If you want demonstration services to be created during the installation, set the deploy_example_services parameter value to true.

     deploy_example_services: true

     Demonstration services can only be created during the initial installation of KUMA. When updating the system using the same inventory file, no demonstration services will be created.

   • If the machines are not registered in your organization's DNS zone, set the generate_etc_hosts parameter to true, and for each machine in the inventory, replace the ip (0.0.0.0) parameter values with the actual IP addresses.

     generate_etc_hosts: true

     When using this parameter, the installer will automatically add the IP addresses of the machines from the inventory file to the /etc/hosts files on the machines where KUMA components are installed.

   • If you are installing KUMA in a production environment and have a separate test machine, set the ansible_connection parameter to ssh:

     ansible_connection: ssh

4. In the inventory file, specify the host of the target machines on which KUMA components should be installed. If the machines are not registered in the DNS zone of your organization, replace the parameter values ip (0.0.0.0) with the actual IP addresses.

   The hosts are specified in the following sections of the inventory file:

   • core is the section for specifying the host and IP address of the target machine on which KUMA Core will be installed. You may only specify one host in this section.
   • collector is the section for specifying the host and IP address of the target machine on which the collector will be installed. You may specify one of more hosts in this section.
   • correlator is the section for specifying the host and IP address of the target machine on which the correlator will be installed. You may specify one of more hosts in this section.
   • storage is the section for specifying the hosts and IP addresses of the target machines on which storage components will be installed. You may specify one of more hosts in this section.

     Storage components: clusters, shards, replicas, and keepers.

     A cluster is a logical group of machines that possess all accumulated normalized KUMA events. It consists of one or more logical shards.

     A shard is a logical group of machines that possess a specific portion of all normalized events accumulated in the cluster. It consists of one or more replicas. Increasing the number of shards lets you do the following:

     • Accumulate more events by increasing the total number of servers and disk space.
     • Absorb a larger stream of events by distributing the load associated with an influx of new events.
     • Reduce the time taken to search for events by distributing search areas among multiple machines.

     A replica is a machine that is a member of the logical shard and possesses a copy of the data of this shard. If there are multiple replicas, there are multiple copies (data is replicated). Increasing the number of replicas lets you do the following:

     • Improve fault tolerance.
     • Distribute the total load related to data searches among multiple machines (although it's best to increase the number of shards for this purpose).

     A keeper is an optional role of a replica that involves the replica's participation in coordinating data replication throughout the entire cluster. There must be at least one replica with this role for the entire cluster. It is recommended to have 3 keeper replicas. The number of replicas involved in coordinating replication must be an odd number.

     Each machine in the storage section can have the following parameter combinations:

     • shard + replica + keeper
     • shard + replica
     • keeper

     If the shard and replica parameters are specified, the machine is a part of a cluster and helps accumulate and search for normalized KUMA events. If the keeper parameter is additionally specified, the machine also helps coordinate data replication at the cluster-wide level.

     If only keeper is specified, the machine will not accumulate normalized events, but it will participate in coordinating data replication at the cluster-wide level. The keeper parameter values must be unique.

     If several replicas are defined within the same shard, the value of the replica parameter must be unique within this shard.

The inventory file is created. It can be used to install KUMA.

It is recommended that you not remove the inventory file after installing KUMA:

• If you change this file (for example, add information about a new server for the collector), you can reuse it to update the system with a new component.
• You can use this inventory file to delete KUMA.

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