README.md

domain	shortname	name	status	obsoleted by	editor	contributors
github.com	3/CFGEN	Configuration Generation	deprecated	18/CFGEN	Valery V. Vorotyntsev <valery.vorotyntsev@seagate.com>	Andriy Tkachuk <andriy.tkachuk@seagate.com>

Configuration Generation

Configuration generation script — cfgen — generates various configuration files required to start Motr cluster.

Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119.

Cluster Description File (CDF)

Cluster administrator SHALL provide a cluster description file (CDF), specifying which hosts the cluster is made of, how many Motr services and clients to run, where to run confd services, which drives to use for Motr I/O.

CDF is a YAML file with the following schema:

nodes:
  - hostname: <str>    # [user@]hostname; e.g., localhost, pod-c1
    data_iface: <str>  # name of network interface; e.g., eth1, eth1:c1
    data_iface_type: tcp|o2ib  # type of network interface;
                               # optional, defaults to "tcp"
    m0_servers:        # optional for client-only nodes
      - runs_confd: <bool>  # optional, defaults to false
        io_disks:
          meta_data: <str>  # device path for meta-data;
                            # optional, Motr will use "/var/motr/m0d-<FID>/"
                            # by default
          data: [ <str> ]   # e.g. [ "/dev/loop0", "/dev/loop1", "/dev/loop2" ]
                            # Empty list means no IO service.
    m0_clients:
      - name: m0_client_other  # name of the motr client
        instances: 2   # Number of instances, this host will run
pools:
  - name: <str>
    type: sns|dix|md   # optional, defaults to "sns";
                       # "sns" - data pool, "dix" - KV, "md" - meta-data pool.
    data_units: <int>
    parity_units: <int>
    spare_units: <int> # optional
    allowed_failures:  # optional section; no failures will be allowed
                       # if this section is missing or all of its elements
                       # are zeroes
      site: <int>
      rack: <int>
      encl: <int>
      ctrl: <int>
      disk: <int>
      #
      # There are two ways of assigning disks to pool:
      #
      # 1) Use all available disks of all nodes for this pool.
      disks: all
      # 2) Choose which disks of which host to use for this pool.
      #disks:
      #  select:
      #    - { host: <str>, path_regex: <str> }

cfgen script

usage: cfgen [OPTION]... CDF

Generate configuration files required to start Motr cluster.

positional arguments:
  CDF                  cluster description file; use '--help-schema' option
                       for format description

optional arguments:
  -h, --help           show this help message and exit
  --help-schema        show the schema of cluster description file (CDF)
  -D dir, --dhall dir  directory with auxiliary Dhall expressions (defaults to
                       '/opt/seagate/cortx/hare/share/cfgen/dhall')
  -o output-dir        output directory (defaults to '.')
  --mock               Generate pseudo-random "facts". The hosts specified in
                       the cluster description file will not be visited and
                       don't even have to exist.
  --debug              print the enriched cluster description and exit
  -V, --version        show program's version number and exit

cfgen reads the CDF, ssh-es to the hosts mentioned in it, collects their "facts" (e.g., number of CPUs, RAM size), and uses that information to generate configuration data.

Output files

• confd.dhall — Motr configuration in Dhall format.

• consul-agents.json — tells bootstrap script where Consul server and client agents should be started and which IP addresses they should bind to.

  Format:

  {
    "servers": [
      {
        "node_name": "<str>",
        "ipaddr": "<str>"
      }
    ],
    "clients": [
      {
        "node_name": "<str>",
        "ipaddr": "<str>"
      }
    ]
  }
  

  "servers" list MUST NOT be empty.

• consul-kv.json — key/value pairs in JSON format, ready to be consumed by consul kv import.