Configuration

Note

The configuration system has changed significantly since version 0.2.10. All existing configurations should still work, but new configurations should follow the new conventions.

Syntax

The Tron configuration file uses YAML syntax. The recommended configuration style requires only strings, decimal values, lists, and dictionaries: the subset of YAML that can be losslessly transformed into JSON. (In fact, your configuration can be entirely JSON, since YAML is mostly a strict superset of JSON.)

Past versions of Tron used additional YAML-specific features such as tags, anchors, and aliases. These features still work in version 0.3, but are now deprecated.

Basic Example

ssh_options:
  agent: true

notification_options:
  smtp_host: localhost
  notification_addr: <your email address>

nodes:
  - name: local
    hostname: 'localhost'

jobs:
  - name: "getting_node_info"
    node: local
    schedule: "interval 10 mins"
    actions:
      - name: "uname"
        command: "uname -a"
      - name: "cpu_info"
        command: "cat /proc/cpuinfo"
        requires: [uname]

Command Context Variables

command attribute values may contain command context variables that are inserted at runtime. The command context is populated both by Tron (see Built-In Command Context Variables) and by the config file (see Command Context). For example:

jobs:
    - name: "command_context_demo"
      node: local
      schedule: "1st monday in june"
      actions:
        - name: "print_run_id"
          # prints 'command_context_demo.1' on the first run,
          # 'command_context_demo.2' on the second, etc.
          command: "echo %(runid)"

SSH

ssh_options (optional)

These options affect how Tron connects to the nodes.

agent (optional, default False)

Set to True if trond should use an SSH agent

identities (optional, default [])

List of paths to SSH identity files

Example:

ssh_options:
    agent: false
    identities:
        - /home/batch/.ssh/id_dsa-nopasswd

Notification Options

notification_options

Email settings for sending failure notices.

smtp_host (required)

SMTP host of the email server

notification_addr (required)

Email address to send mail to

Example:

notification_options:
    smtp_host: localhost
    notification_addr: batch+errors@example.com

Time Zone

time_zone (optional)

Local time as observed by the system clock. If your system is obeying a time zone with daylight savings time, then some of your jobs may run early or late on the days bordering each mode. See Notes on Daylight Saving Time for more information.

Example:

time_zone: US/Pacific

Command Context

command_context

Dictionary of custom command context variables. It is an arbitrary set of key-value pairs.

Example:

command_context:
    PYTHON: /usr/bin/python
    TMPDIR: /tmp

See a list of Built-In Command Context Variables.

Output Stream Directory

output_stream_dir

A path to the directory used to store the stdout/stderr logs from jobs. It defaults to the --working_dir option passed to trond.

Example:

output_stream_dir: "/home/tronuser/output/"

State Persistence

state_persistence

Configure how trond should persist its state to disk. By default a shelve store is used and saved to ./tron_state in the working directory.

store_type

Valid options are:

shelve - uses the shelve module and saves to a local file

sql - uses sqlalchemy to save to a database (tested with version 0.7).

mongo - uses pymongo to save to a mongodb (tested with version 2.2).

yaml - uses yaml and saves to a local file (this is not recommend and is provided to be backwards compatible with previous versions of Tron).

You will need the appropriate python module for the option you choose.

name

The name of this store. This will be the filename for a shelve or yaml store, or the database name for a mongo store. It is just a label when used with an sql store.

connection_details

Ignored by shelve and yaml stores.

A connection string (see sqlalchemy engine configuration) when using an sql store.

An HTTP query string when using mongo. Valid keys are: hostname, port, username, password. Example: "hostname=localhost&port=5555"

buffer_size

The number of save calls to buffer before writing the state. Defaults to 1, which is no buffering.

Example:

state_persistence:
    store_type: sql
    name: local_sqlite
    connection_details: "sqlite:///dest_state.db"
    buffer_size: 1 # No buffer

Nodes

nodes

List of nodes, each with a name and a hostname. name defaults to hostname. Each of these nodes should be configured to allow SSH connections from trond.

Example:

nodes:
    - name: node1
      hostname: 'batch1'
    - hostname: 'batch2'    # name is 'batch2'

Node Pools

node_pools

List of node pools, each with a name and nodes list. name defaults to the names of each node joined by underscores.

Example:

node_pools:
    - name: pool
      nodes: [node1, batch1]
    - nodes: [batch1, node1]    # name is 'batch1_node1'

Jobs and Actions

jobs

List of jobs for Tron to manage. See Jobs for the options available to jobs and their actions.

Services

services

List of services for Tron to manage. See Services for the options available to services.

Logging

As of v0.3.3 Logging is no longer configured in the tron configuration file.

Tron uses Python’s standard logging and by default uses a rotating log file handler that rotates files each day. The default log directory is /var/log/tron/tron.log.

To configure logging pass -l <logging.conf> to trond. You can modify the default logging.conf by copying it from tron/logging.conf. See http://docs.python.org/howto/logging.html#configuring-logging