Pacemaker MCP

Pacemaker MCP

Model Context Protocol (MCP) server that exposes Pacemaker pcs commands as safe, guardrailed tools over stdio. It connects to a target cluster node via SSH using your OpenSSH config (Host alias; optional sudo) and runs read-only status queries and controlled operations. Ideal for using Pacemaker safely from MCP-aware clients like Cursor or Claude.

Features

• Pacemaker tools: pcs_cluster_status, pcs_node_status, pcs_resource_list.
• Logs access: pcs_logs_common, pcs_logs_tail, pcs_logs_journalctl for Pacemaker/Corosync troubleshooting.
• Key-based auth via OpenSSH config: uses your ~/.ssh/config Host alias; optional sudo.
• Configurable: JSON/YAML config file or environment variables for alias and options.

Requirements

• Node.js >= 18
• Access to a Pacemaker cluster node over SSH

Setup (from scratch)

# 1) Install dependencies
npm install

# 2) Build the server (emits dist/index.js)
npm run build

# 3) (Optional) Verify locally with MCP Inspector
npx @modelcontextprotocol/inspector@latest node $(pwd)/dist/index.js

You can also run directly with Node:

node dist/index.js

Configure connection (single method)

Use your OpenSSH config (e.g., ~/.ssh/config) with a Host alias, and reference that alias. This is the only connection method used by the server.

• Set a Host entry in your OpenSSH config file:

Host my-cluster
  HostName cluster-node.example.com
  User ec2-user
  IdentityFile ~/.ssh/id_rsa
  Port 22

• If you use a bastion, either define it with ProxyJump or a ProxyCommand (both are supported):

Host my-cluster
  HostName 10.1.30.239
  User root
  IdentityFile ~/.ssh/aws-instance_rsa
  StrictHostKeyChecking no
  UserKnownHostsFile /dev/null
  # Option A (preferred): use a Host alias for the bastion
  # ProxyJump bastion
  # Option B: ProxyCommand (will be auto-translated)
  ProxyCommand ssh -W %h:%p bastion -i ~/.ssh/aws-bastion_rsa -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null

Host bastion
  HostName bastion.example.com
  User ec2-user
  IdentityFile ~/.ssh/aws-bastion_rsa

• Then either:
  • Provide alias per-call as args: sshConfigHost: "my-cluster" (and optionally sshConfigPath if not ~/.ssh/config)
  • Or put it in your Pacemaker MCP config file (JSON/YAML) via PACEMAKER_MCP_CONFIG:

default:
  sshConfigHost: my-cluster
  # sshConfigPath: /absolute/path/to/ssh_config   # optional, defaults to ~/.ssh/config
  sudo: true

Notes:

• This server reads connection parameters exclusively from the OpenSSH alias (HostName, User, Port, IdentityFile).
• If your ssh config has StrictHostKeyChecking no for the alias, unknown host keys will be accepted unless overridden.
• ProxyCommand lines like ssh -W %h:%p <jump> -i <key> ... are supported; they are treated as a single-hop ProxyJump automatically.
• If IdentityFile is not set, the SSH agent (SSH_AUTH_SOCK) is used if available.
• If User is not set, your local username is used by default.

Configuration sources (last-wins per field):

• Config file from PACEMAKER_MCP_CONFIG (or default search paths)
• Environment variables (e.g., PACEMAKER_SSH_CONFIG_HOST, PACEMAKER_USE_SUDO)
• Per-tool arguments (sshConfigHost, sshConfigPath, sudo)

Use with MCP clients

Cursor

1. Build so dist/index.js exists: npm run build

2. Add the server to your global Cursor MCP config (macOS: ~/.cursor/mcp.json). Use absolute paths.

{
  "mcpServers": {
    "pacemaker-mcp-server": {
      "command": "node",
      "args": ["/absolute/path/to/pcs_mcp/dist/index.js"],
      "env": {
        "PACEMAKER_SSH_CONFIG_HOST": "my-cluster",
        "PACEMAKER_USE_SUDO": "true"
      }
    }
  }
}

Restart Cursor after saving.

Claude Desktop

1. Build dist/index.js: npm run build

2. Add the server to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS), then restart Claude. Use absolute paths.

{
  "mcpServers": {
    "pacemaker-mcp-server": {
      "command": "node",
      "args": ["/absolute/path/to/pcs_mcp/dist/index.js"],
      "env": {
        "PACEMAKER_MCP_CONFIG": "/absolute/path/to/pacemaker.yaml",
        "PACEMAKER_SSH_CONFIG_HOST": "my-cluster",
        "PACEMAKER_USE_SUDO": "false",
        "PACEMAKER_SSH_READY_TIMEOUT_MS": "30000"
      }
    }
  }
}

Notes:

• Prefer absolute paths in args and file-based env like PACEMAKER_MCP_CONFIG.
• Configure connection via OpenSSH Host alias; set the alias through env or your MCP config file.
• For production, prefer key-based SSH and passwordless sudo if sudo is required.

Troubleshooting

• Handshake timeout:
  • Set PACEMAKER_SSH_DEBUG=true and retry; inspect logs for where it stalls (jump vs target vs auth).
  • Increase PACEMAKER_SSH_READY_TIMEOUT_MS (e.g., 30000).
  • Verify your alias works in a terminal: ssh my-cluster 'echo ok'.
  • If using a bastion, ensure ProxyJump or a correct ProxyCommand is defined and keys are accessible.
  • If host key checks block you in dev/test, set StrictHostKeyChecking no and UserKnownHostsFile /dev/null in your SSH config or set PACEMAKER_INSECURE_ACCEPT_UNKNOWN_HOST_KEYS=true.

Available tools (examples)

• pcs_cluster_status: returns pcs cluster status
• pcs_node_status: returns pcs status nodes
• pcs_resource_list: returns pcs resource config
• pcs_logs_common: tail common log files and optionally journal; e.g., last 200 lines of Pacemaker/Corosync logs
  • args: { "lines": 200, "includeJournal": true }
• pcs_logs_tail: tail specific log files
  • args: { "paths": ["/var/log/pacemaker/pacemaker.log", "/var/log/cluster/corosync.log"], "lines": 500 }
• pcs_logs_journalctl: read journal for units (defaults to pacemaker and corosync)
  • args: { "units": ["pacemaker", "corosync"], "lines": 300, "since": "2 hours ago", "priority": "warning", "grep": "fail|error" }

Each tool accepts a cluster name from config or sshConfigHost/sshConfigPath, and sudo.

Security considerations

• Prefer key-based SSH; avoid passwords when possible.
• Set PACEMAKER_INSECURE_ACCEPT_UNKNOWN_HOST_KEYS=false in production.
• Only use sudo if required by your environment.

Development

npm run typecheck
npm run build
# Run from TS directly (dev):
npm run dev

Open with MCP Inspector (from dist output):

npx @modelcontextprotocol/inspector@latest node $(pwd)/dist/index.js

See CONTRIBUTING.md for PR guidelines.

License

MIT. See LICENSE.