LITELLM_BACKEND_ROLES read lookup('deployment').groups, which deployment.py
fills from group_names. That variable is host-scoped: it lists only the groups
the host currently being processed belongs to.
On a swarm round the manager carries svc-ai-ollama, svc-ai-lmstudio and
svc-ai-litellm while the workers carry three groups and none of them is an AI
backend. Both branches of LITELLM_CHAT_MODEL therefore missed on a worker and,
with OPENROUTER_API_KEY empty, the model resolved to the empty string.
Only one task made that visible. Every stateful task in the gateway include
carries delegate_to STACK_HOST plus run_once, so it templates in the manager's
scope and wrote the correct model into the database. The assert carries
neither, so it re-templated in each worker's own scope and failed there while
the manager passed.
The manager-only membership is not a placement decision. The swarm test
inventory is provisioned with a single --host MGR, so every role of the round's
closure gets that one host, and extend_inventory then widens only
svc-swarm-node, svc-storage-nfs-client, svc-storage-nfs-server and the round's
own application. The three AI roles declare no placement at all; they are
manager-only because nothing widened them.
Add an inventory selector next to the host-scoped one, built from the play-wide
groups magic var, skipping groups without hosts and Ansible's implicit all and
ungrouped, sorted so the cache key is stable. The key takes it too, or two
hosts with equal group_names but different inventories would share an entry.
The blast radius is two readers, both in 16_ai.yml, and both ask only whether
svc-ai-ollama or svc-ai-lmstudio is present. On the manager the new value gains
exactly svc-storage-nfs-server and svc-bkp-nfs-2-local, neither of which either
reader tests, so the manager's answer does not move and only the workers change,
to match it.
This is the third step on the same line. 46a16127fc set .running; b149ad0d22
corrected that to .groups because a targeted apps= round leaves only the
command-line roles in the whitelist. .groups solves the targeted round and not
the multi-host one, because group_names stays host-scoped either way.
Measured in a two-host play with a real group_vars file and the real lookup:
the worker resolves ollama false through group_names and true through the new
selector, the manager is true both ways, and the assert that failed in CI
passes on both hosts.
Requirement 036 named the host-scoped backend selection as the thing that has
to change and deferred it. That residual is closed, so the paragraph now
describes the selector in use and why the two rejected ones are wrong.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Ansible Plugins (plugins/) 🧩
This document is the central reference for plugin types and plugin placement in Infinito.Nexus.
Not to be confused with application addons. This
plugins/directory holds Ansible plugins (action / filter / lookup) that extend the automation engine itself. Some applications also call their own extensions "plugins" (e.g. Nextcloud, WordPress). Those application-level extensions, whatever the app calls them natively, are declared through the unifiedmeta/addons/contract, documented in Unified Addons. An app "plugin" is an addon; an Ansible plugin lives here.
Current Project Layout 🗂️
plugins/
├── action/ # custom action plugins
├── filter/ # custom Jinja2 filters
└── lookup/ # custom lookup plugins
Configured plugin paths in this repository are defined in ansible.cfg:
action_plugins = ./plugins/actionfilter_plugins = ./plugins/filterlookup_plugins = ./plugins/lookup
All Common Ansible Plugin Types 📚
The table below summarizes common Ansible plugin types and their conventional directory names.
| Emoji | Plugin Type | Conventional Directory | Purpose |
|---|---|---|---|
| ⚙️ | action |
action_plugins/ or plugins/action/ |
Wrap/extend module execution behavior at task runtime. |
| 🔐 | become |
become_plugins/ |
Implement privilege escalation methods. |
| 💾 | cache |
cache_plugins/ |
Persist gathered facts and cached data between runs. |
| 📣 | callback |
callback_plugins/ |
React to play/task events (logging, reporting, notifications). |
| 🖧 | cliconf |
cliconf_plugins/ |
Define CLI command transport behavior (mainly network platforms). |
| 🔌 | connection |
connection_plugins/ |
Control how Ansible connects to targets (ssh, local, etc.). |
| 🔍 | filter |
filter_plugins/ or plugins/filter/ |
Add Jinja2 filters for data transformation. |
| 🌐 | httpapi |
httpapi_plugins/ |
API transport layer over HTTP(S), mainly for network devices. |
| 🧭 | inventory |
inventory_plugins/ |
Build dynamic inventories from APIs, services, or files. |
| 👉 | lookup |
lookup_plugins/ or plugins/lookup/ |
Resolve dynamic values during playbook processing. |
| 🛰️ | netconf |
netconf_plugins/ |
NETCONF transport integration for network automation. |
| 🐚 | shell |
shell_plugins/ |
Adjust shell command wrapping/execution behavior. |
| 🧠 | strategy |
strategy_plugins/ |
Customize task scheduling/execution strategy. |
| ✅ | test |
test_plugins/ |
Add Jinja2 tests used in conditions and templates. |
| 📦 | vars |
vars_plugins/ |
Load variables from custom sources. |
Which Plugin Type to Use 🧭
action ⚙️
Use when task execution behavior itself must be changed or wrapped.
Examples:
- centralized retry logic (
uri_retry.py), - argument normalization before module dispatch,
- pre/post task orchestration.
filter 🔍
Use for pure data transformation in Jinja2 expressions.
Examples:
- mapping/normalizing dictionaries,
- deriving computed fields for templates,
- deterministic formatting helpers.
lookup 👉
Use when a value must be dynamically resolved at runtime.
Examples:
- computing IDs from role metadata,
- resolving paths/version data,
- reading structured project data for templates/tasks.
callback 📣
Use to hook into execution events and shape output/reporting.
inventory 🧭
Use when host/group data should come from a dynamic source.
strategy 🧠
Use to alter how tasks are scheduled/executed across hosts.
vars 📦
Use to load variables from custom backends.
connection, become, shell 🔌🔐🐚
Use to customize low-level execution and privilege mechanics.
cache 💾
Use to persist facts/results across runs for performance and consistency.
cliconf, httpapi, netconf 🖧🌐🛰️
Use in network automation contexts requiring protocol-specific transport behavior.
test ✅
Use to add custom Jinja2 test operators for conditional logic.
Best Practices 🧪
- Keep plugin interfaces explicit and stable.
- Keep plugin logic focused; move shared logic to
utils/. - Add unit tests for plugin behavior and integration tests for end-to-end flows.
- Prefer deterministic outputs and avoid hidden global state.
- Document any plugin-specific task arguments in the plugin docstring and README.
References 🔗
- Ansible plugin development: docs.ansible.com
- Ansible plugin index (all types): docs.ansible.com
- Ansible
ansible-docplugin types:ansible-doc -t ...