Choria Server is designed to not open any listening ports unless its Apple HomeKit integration is enabled.

Without any opening ports monitoring it is via a state file that it writes regularly when enabled:

plugin.choria.status_file_path = /var/log/choria-status.json
plugin.choria.status_update_interval = 30

The above configuration will cause the status file to update every 30 seconds. This needs to be enabled for any deep introspection.

Nagios Check

A nagios protocol test is included in the command choria tool status, this can check various aspects of the server operation.

$ choria tool status --status-file /var/log/choria-status.json \
    --disconnected \        # alerts when the server is not connected to a broker
    --message-since 1h \    # must have received RPC requests within the last 1 hour
    --max-age 1m \          # Status file may not be older than 1 minute
    --token-age 24h \       # Alert 1 day before the token expires
    --certificate-age 24h \ # Alert 1 day before the certificate expires
    --provisioned           # Alerts if the server is in provisioned mode

Autonomous Agent Check

A running instance can check itself using an Autonomous Agent, it will then public Cloud Events about it’s internal state and, optionally, expose it’s state to a local Prometheus Node Exporter via its text file directory.

  - name: check_choria
    type: nagios
    interval: 5m # checks every 5 minutes, require the status file to be 15 minutes or newer
      builtin: choria_status
      token_expire: 1d    # alerts when the token expires soon
      pubcert_expire: 1d  # alerts when the certificate expires soon
      last_message: 1h    # alerts when no RPC message was received in 1 hour

Review the Autonomous Agent section for full detail about these checks.

If you have Prometheus Node Exporter running locally with an argument set you can configure this path in Choria which would cause the above Autonomous Agent to write status to that directory:

plugin.choria.prometheus_textfile_directory = /var/lib/node_exporter/textfile

Lifecycle Events

Choria will publish a number of events in Cloud Events format, these can be observed using choria tool event, this will include start, stop, provisioned etc events from every Choria Server instance.

Some details about these events are in these blog posts: