The actor-IaC Journey: From v2.6.0 to v2.12.0

A retrospective on the evolution of actor-IaC, the Infrastructure-as-Code tool built on POJO-actor. This post covers the major milestones from the initial release (v2.6.0) through v2.12.0.

What is actor-IaC?

actor-IaC is an Infrastructure-as-Code tool that leverages the POJO-actor workflow engine for infrastructure automation. It executes commands on remote nodes via SSH and records all operations in an H2 database for complete traceability.

Key design principles:

• POJO-actor foundation: Inherits the state-machine workflow engine
• SSH-focused: Specialized for SSH-based remote execution
• H2 logging: Full traceability with local database
• Ansible-compatible: Supports INI inventory file format
• AI-Native: YAML-based state machines that AI agents can easily generate

v2.6.0 (December 31, 2025) - The Beginning

The first release established the core architecture.

Core Components

Node: A POJO managing SSH connections to a single node.

NodeGroup (formerly Cluster): Manages multiple nodes and batch operations.

# Example: Execute on all nodes in a group
- actor: nodeGroup
  method: apply
  arguments:
    actor: "node-*"
    method: executeCommand
    arguments: ["hostname"]

SSH Execution

• JSch/Mina-based command execution
• ssh-agent or password authentication
• Host-specific variables support

HashiCorp Vault Integration

Secure management of SSH keys and sudo passwords through Vault integration.

Design Philosophy

The three-level usage pattern was documented:

• Level 1: Pure POJOs without ActorSystem/ActorRef
• Level 2: ActorRef-based coordination
• Level 3: Full actor system with supervision

---

v2.7.0 (December 31, 2025) - ExecutionMode

Added support for POJO-actor 2.7.0's ExecutionMode feature.

// Choose between POOL (thread pool) or DIRECT execution
ActorSystem system = ActorSystem.create(ExecutionMode.POOL);

---

v2.8.0 (January 3, 2026) - Parallel Execution

NodeGroupInterpreter

A dedicated workflow interpreter for node groups, enabling parallel command execution across multiple nodes.

# Parallel execution across nodes
- actor: nodeGroup
  method: apply
  arguments:
    actor: "node-*"
    method: runWorkflow
    arguments: ["setup.yaml"]

Error Handling Options

• continue-on-failure: Continue processing other nodes even if some fail
• fail-fast: Stop at the first error (optional)

This was crucial for real-world deployments where some nodes might be unreachable.

---

v2.9.0 (January 6, 2026) - Major CLI and Logging Overhaul

This release transformed actor-IaC from a library into a practical CLI tool.

YAML Overlay Support

Kustomize-style environment customization:

# base.yaml
steps:
  - states: ["0", "1"]
    actions:
      - actor: this
        method: executeCommand
        arguments: ["echo 'Hello'"]

# production-overlay.yaml
patches:
  - target: steps[0].actions[0].arguments
    value: ["echo 'Hello Production'"]

H2 Database Logging

All workflow executions are now logged by default:

• Session management (start/end time, status)
• Per-node log entries
• Complete command output history

JBang CLI Wrapper

The actor_iac.java script made it easy to run workflows:

./actor_iac.java run -w workflow.yaml -i inventory.ini

New CLI Options

Option	Description
--limit	Filter target nodes
--ask-pass	Prompt for SSH password
-v/--verbose	Verbose output mode

SSH Improvements

• Prioritized ssh-agent usage (Ed25519 key support)
• ProxyJump (bastion/jump host) support

---

v2.10.0 (January 10, 2026) - Centralized Logging

H2 Log Server

A centralized log server for multi-process environments:

# Start log server
./actor_iac.java log-serve

# Run workflow (auto-discovers server)
./actor_iac.java run -w workflow.yaml -i inventory.ini

The server runs on TCP port 29090 by default, allowing multiple workflow processes to write to a single log database.

CLI Refactoring

Verb-based command naming:

# Old
./actor_iac.java --describe workflow.yaml

# New
./actor_iac.java describe workflow.yaml
./actor_iac.java run -w workflow.yaml
./actor_iac.java log-show
./actor_iac.java log-serve

Log Merge

Consolidate distributed logs into a single database:

./actor_iac.java merge-logs node1.db node2.db -o combined.db

Enhanced Log Queries

# Filter by relative time
./actor_iac.java log-show --since 1h

# Filter by end time
./actor_iac.java log-show --ended-since 30m

# List nodes in a session
./actor_iac.java log-show --list-nodes --session 42

---

v2.11.0 (January 11, 2026) - Maven Central & Auto-Discovery

Log Server Auto-Discovery

The log server now starts automatically in the background and is discovered by workflow runners without configuration.

Maven Central Publication

actor-IaC became available on Maven Central:

<dependency>
    <groupId>com.scivicslab</groupId>
    <artifactId>actor-IaC</artifactId>
    <version>2.11.0</version>
</dependency>

---

v2.12.0 (January 18, 2026) - Terminology & Patterns

Terminology Unification

Aligned with POJO-actor 2.12.0's terminology changes:

Old	New
Vertex	Transition
vertex_name	label

This made the workflow DSL more intuitive.

MultiplexerAccumulator Pattern

Unified log output management with simultaneous writes to multiple destinations:

MultiplexerAccumulator acc = new MultiplexerAccumulator();
acc.addTarget(consoleOut);
acc.addTarget(fileOut);
acc.addTarget(h2Logger);

Automatic Node Actor Creation

Nodes are now automatically created as actors from inventory:

# inventory.ini
[compute]
server01 ansible_host=192.168.1.1
server02 ansible_host=192.168.1.2

# These actors are auto-created
- actor: node-server01
  method: executeCommand
  arguments: ["hostname"]

Other Improvements

• -l/--log option for opt-in text logging
• --cowfile option for cowsay character selection
• ISO 8601 timestamp format
• Enhanced SSH diagnostic messages

---

Evolution Summary

Feature Timeline

Version	Date	Key Features
v2.6.0	2025-12-31	Initial release, SSH execution, NodeGroup
v2.7.0	2025-12-31	ExecutionMode support
v2.8.0	2026-01-03	NodeGroupInterpreter, continue-on-failure
v2.9.0	2026-01-06	YAML overlay, H2 logging, JBang CLI
v2.10.0	2026-01-10	Log server, merge-logs, describe
v2.11.0	2026-01-11	Auto-discovery, Maven Central
v2.12.0	2026-01-18	Transition terminology, MultiplexerAccumulator

POJO-actor Correspondence

actor-IaC versions are aligned with POJO-actor versions:

actor-IaC	POJO-actor	Integration Feature
v2.6.0	v2.6.0	Workflow engine
v2.7.0	v2.7.0	ExecutionMode
v2.8.0	v2.8.0	Sub-workflows, state patterns
v2.9.0	v2.9.0	YAML overlay
v2.10.0	v2.10.0	JSON State API
v2.11.0	v2.11.0	Simultaneous Maven Central release
v2.12.0	v2.12.0	Transition terminology, ManagedThreadPool

What's Next?

Check out actor-IaC v2.13.0 for the latest features including WorkflowReporter, Java plugin support, and the AptLockChecker plugin.

References

• Documentation: actor-IaC Docs
• GitHub: scivicslab/actor-IaC
• Javadoc: API Reference
• Maven Central: com.scivicslab:actor-IaC
• POJO-actor: https://github.com/scivicslab/POJO-actor