Process Config¶

This config resides in /etc/lithos/processes/NAME.yaml (by default). Where NAME is the name of a sandbox.

It mainly contains three things:

image the process is run from
config file name inside the image that specifies command-line and other process execution parameters
number instances of the process to run

For example:

django:
    image: django.v3.5.7
    config: /config/worker_process.yaml
    instances: 3

redis:
    image: redix.v1
    config: /config/redis.yaml
    instances: 1

This will start three python django worker processes and one redis.

Hint

Usually this config is generated by some tool like ansible or confd.

There is also a way to create ad-hoc commands. For example:

manage:
    kind: Command
    image: django.v3.5.7
    config: /config/manage_py.yaml

This will allow to start a manage.py command with:

$ lithos_cmd SANDBOX_NAME manage syncdb

This runs command in the same sandbox like the worker process itself but the command is actually attached to current shell. The commands may be freely mixed with Daemon items (which is default kind) in same config. The only limitation is that names must not be duplicated

The Command is occasionally useful, but should be used with care. To start a command you need root privileges on host system, so it’s only useful for SysOp tasks or may be for cron tasks but not for normal operation of application.

Options¶

instances¶: Number of instances to run

image¶: Identifier of the image to run container from

config¶: Configuration file name (absolute name in container) to run

ip-addresses¶: A list of ip addresses if bridged-network is enforced in sandbox. Note the number of items in this list must match instances value.

variables¶: A mapping of variable: value for variables that can be used in process config.

extra-secrets-namespaces¶: Additional secrets namespaces allowed for this specific project. In addition to secrets-namespaces. See Encrypted Variables for more info.

Variables¶

You can also add variables for specific config:

For example:

django:
    image: django.v3.5.7
    config: /config/worker_process.yaml
    variables:
      tcp_port: 10001
    instances: 3

Only variables that are declared in container config can be substituted. Extra variables are ignored. If there is a declared variable but it’s not present in process config, it doesn’t pass configuration check.