feat: Add SSH remote execution for HAProxy on remote host

MCP server can now manage HAProxy running on a remote host via SSH.
When SSH_HOST env var is set, all file I/O and subprocess commands
(podman, acme.sh, openssl) are routed through SSH instead of local exec.

- Add ssh_ops.py module with remote_exec, run_command, file I/O helpers
- Modify file_ops.py to support remote reads/writes via SSH
- Update all tools (domains, certificates, health, configuration) for SSH
- Fix domains.py: replace direct fcntl usage with file_lock context manager
- Add openssh-client to Docker image for SSH connectivity
- Update k8s deployment with SSH env vars and SSH key secret mount

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Dockerfile

@@ -12,6 +12,8 @@ COPY haproxy_mcp/ ./haproxy_mcp/
 
 FROM python:3.11-slim
 
+RUN apt-get update && apt-get install -y --no-install-recommends openssh-client && rm -rf /var/lib/apt/lists/*
+
 WORKDIR /app
 
 COPY --from=builder /usr/local/lib/python3.11/site-packages /usr/local/lib/python3.11/site-packages

haproxy_mcp/config.py

@@ -44,6 +44,13 @@ MAX_SLOTS: int = int(os.getenv("HAPROXY_MAX_SLOTS", "10"))
 # Container configuration
 HAPROXY_CONTAINER: str = os.getenv("HAPROXY_CONTAINER", "haproxy")
 
+# SSH remote execution (when MCP runs on a different host from HAProxy)
+SSH_HOST: str = os.getenv("SSH_HOST", "")  # Empty = local mode
+SSH_USER: str = os.getenv("SSH_USER", "root")
+SSH_KEY: str = os.getenv("SSH_KEY", "")  # Path to SSH private key
+SSH_PORT: int = int(os.getenv("SSH_PORT", "22"))
+REMOTE_MODE: bool = bool(SSH_HOST)
+
 # Validation patterns - compiled once for performance
 DOMAIN_PATTERN = re.compile(
     r'^[a-zA-Z0-9]([a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])?'

haproxy_mcp/file_ops.py

@@ -12,6 +12,7 @@ from .config import (
     WILDCARDS_MAP_FILE,
     SERVERS_FILE,
     CERTS_FILE,
+    REMOTE_MODE,
     logger,
 )
 from .validation import domain_to_backend
@@ -21,22 +22,19 @@ from .validation import domain_to_backend
 def file_lock(lock_path: str) -> Generator[None, None, None]:
     """Acquire exclusive file lock for atomic operations.
 
-    This context manager provides a consistent locking mechanism for
+    In REMOTE_MODE, locking is skipped (single-writer assumption
-    read-modify-write operations on configuration files to prevent
+    with atomic writes on the remote host).
-    race conditions during concurrent access.
 
     Args:
         lock_path: Path to the lock file (typically config_file.lock)
 
     Yields:
         None - the lock is held for the duration of the context
-
-    Example:
-        with file_lock("/path/to/config.json.lock"):
-            config = load_config()
-            config["key"] = "value"
-            save_config(config)
     """
+    if REMOTE_MODE:
+        yield
+        return
+
     with open(lock_path, 'w') as lock_file:
         fcntl.flock(lock_file.fileno(), fcntl.LOCK_EX)
         try:
@@ -55,6 +53,11 @@ def atomic_write_file(file_path: str, content: str) -> None:
     Raises:
         IOError: If write fails
     """
+    if REMOTE_MODE:
+        from .ssh_ops import remote_write_file
+        remote_write_file(file_path, content)
+        return
+
     dir_path = os.path.dirname(file_path)
     fd = None
     temp_path = None
@@ -91,29 +94,49 @@ def _read_map_file(file_path: str) -> list[tuple[str, str]]:
     """
     entries = []
     try:
-        with open(file_path, "r", encoding="utf-8") as f:
+        content = _read_file(file_path)
-            try:
+        for line in content.splitlines():
-                fcntl.flock(f.fileno(), fcntl.LOCK_SH)
-            except OSError as e:
-                logger.debug("File locking not supported for %s: %s", file_path, e)
-            try:
-                for line in f:
             line = line.strip()
             if not line or line.startswith("#"):
                 continue
             parts = line.split()
             if len(parts) >= 2:
                 entries.append((parts[0], parts[1]))
-            finally:
-                try:
-                    fcntl.flock(f.fileno(), fcntl.LOCK_UN)
-                except OSError as e:
-                    logger.debug("File unlock failed for %s: %s", file_path, e)
     except FileNotFoundError:
         logger.debug("Map file not found: %s", file_path)
     return entries
 
 
+def _read_file(file_path: str) -> str:
+    """Read a file locally or remotely based on REMOTE_MODE.
+
+    Args:
+        file_path: Path to the file
+
+    Returns:
+        File contents as string
+
+    Raises:
+        FileNotFoundError: If file doesn't exist
+    """
+    if REMOTE_MODE:
+        from .ssh_ops import remote_read_file
+        return remote_read_file(file_path)
+
+    with open(file_path, "r", encoding="utf-8") as f:
+        try:
+            fcntl.flock(f.fileno(), fcntl.LOCK_SH)
+        except OSError as e:
+            logger.debug("File locking not supported for %s: %s", file_path, e)
+        try:
+            return f.read()
+        finally:
+            try:
+                fcntl.flock(f.fileno(), fcntl.LOCK_UN)
+            except OSError:
+                pass
+
+
 def get_map_contents() -> list[tuple[str, str]]:
     """Read both domains.map and wildcards.map and return combined entries.
 
@@ -250,24 +273,14 @@ def get_backend_and_prefix(domain: str) -> tuple[str, str]:
 
 
 def load_servers_config() -> dict[str, Any]:
-    """Load servers configuration from JSON file with file locking.
+    """Load servers configuration from JSON file.
 
     Returns:
         Dictionary with server configurations
     """
     try:
-        with open(SERVERS_FILE, "r", encoding="utf-8") as f:
+        content = _read_file(SERVERS_FILE)
-            try:
+        return json.loads(content)
-                fcntl.flock(f.fileno(), fcntl.LOCK_SH)
-            except OSError:
-                logger.debug("File locking not supported for %s", SERVERS_FILE)
-            try:
-                return json.load(f)
-            finally:
-                try:
-                    fcntl.flock(f.fileno(), fcntl.LOCK_UN)
-                except OSError:
-                    pass
     except FileNotFoundError:
         return {}
     except json.JSONDecodeError as e:
@@ -398,19 +411,9 @@ def load_certs_config() -> list[str]:
         List of domain names
     """
     try:
-        with open(CERTS_FILE, "r", encoding="utf-8") as f:
+        content = _read_file(CERTS_FILE)
-            try:
+        data = json.loads(content)
-                fcntl.flock(f.fileno(), fcntl.LOCK_SH)
-            except OSError as e:
-                logger.debug("File locking not supported for %s: %s", CERTS_FILE, e)
-            try:
-                data = json.load(f)
         return data.get("domains", [])
-            finally:
-                try:
-                    fcntl.flock(f.fileno(), fcntl.LOCK_UN)
-                except OSError as e:
-                    logger.debug("File unlock failed for %s: %s", CERTS_FILE, e)
     except FileNotFoundError:
         return []
     except json.JSONDecodeError as e:

haproxy_mcp/haproxy_client.py

@@ -1,7 +1,6 @@
 """HAProxy Runtime API client functions."""
 
 import socket
-import subprocess
 import select
 import time
 
@@ -14,6 +13,7 @@ from .config import (
     SUBPROCESS_TIMEOUT,
 )
 from .exceptions import HaproxyError
+from .ssh_ops import run_command
 
 
 def haproxy_cmd(command: str) -> str:
@@ -147,23 +147,23 @@ def reload_haproxy() -> tuple[bool, str]:
         Tuple of (success, message)
     """
     try:
-        validate = subprocess.run(
+        validate = run_command(
             ["podman", "exec", HAPROXY_CONTAINER, "haproxy", "-c", "-f", "/usr/local/etc/haproxy/haproxy.cfg"],
-            capture_output=True, text=True, timeout=SUBPROCESS_TIMEOUT
+            timeout=SUBPROCESS_TIMEOUT,
         )
         if validate.returncode != 0:
             return False, f"Config validation failed:\n{validate.stderr}"
 
-        result = subprocess.run(
+        result = run_command(
             ["podman", "kill", "--signal", "USR2", HAPROXY_CONTAINER],
-            capture_output=True, text=True, timeout=SUBPROCESS_TIMEOUT
+            timeout=SUBPROCESS_TIMEOUT,
         )
         if result.returncode != 0:
             return False, f"Reload failed: {result.stderr}"
         return True, "OK"
-    except subprocess.TimeoutExpired:
+    except TimeoutError:
         return False, f"Command timed out after {SUBPROCESS_TIMEOUT} seconds"
     except FileNotFoundError:
-        return False, "podman command not found"
+        return False, "ssh/podman command not found"
     except OSError as e:
         return False, f"OS error: {e}"

haproxy_mcp/ssh_ops.py

@@ -0,0 +1,149 @@
+"""SSH remote execution for HAProxy MCP Server.
+
+When REMOTE_MODE is enabled (SSH_HOST is set), file I/O and subprocess
+commands are executed on the remote HAProxy host via SSH.
+"""
+
+import subprocess
+from .config import (
+    SSH_HOST,
+    SSH_USER,
+    SSH_KEY,
+    SSH_PORT,
+    REMOTE_MODE,
+    SUBPROCESS_TIMEOUT,
+    logger,
+)
+
+
+def _ssh_base_cmd() -> list[str]:
+    """Build base SSH command with options."""
+    cmd = [
+        "ssh",
+        "-o", "StrictHostKeyChecking=no",
+        "-o", "BatchMode=yes",
+        "-o", "ConnectTimeout=10",
+        "-p", str(SSH_PORT),
+    ]
+    if SSH_KEY:
+        cmd.extend(["-i", SSH_KEY])
+    cmd.append(f"{SSH_USER}@{SSH_HOST}")
+    return cmd
+
+
+def remote_exec(command: str, timeout: int = SUBPROCESS_TIMEOUT) -> subprocess.CompletedProcess:
+    """Execute a command on the remote host via SSH.
+
+    Args:
+        command: Shell command to execute remotely
+        timeout: Command timeout in seconds
+
+    Returns:
+        CompletedProcess with stdout/stderr
+
+    Raises:
+        subprocess.TimeoutExpired: If command times out
+        OSError: If SSH command fails to execute
+    """
+    ssh_cmd = _ssh_base_cmd() + [command]
+    logger.debug("SSH exec: %s", command)
+    return subprocess.run(
+        ssh_cmd,
+        capture_output=True,
+        text=True,
+        timeout=timeout,
+    )
+
+
+def remote_read_file(path: str) -> str:
+    """Read a file from the remote host.
+
+    Args:
+        path: Absolute file path on remote host
+
+    Returns:
+        File contents as string
+
+    Raises:
+        FileNotFoundError: If file doesn't exist on remote
+        IOError: If read fails
+    """
+    result = remote_exec(f"cat {path}")
+    if result.returncode != 0:
+        stderr = result.stderr.strip()
+        if "No such file" in stderr:
+            raise FileNotFoundError(f"Remote file not found: {path}")
+        raise IOError(f"Failed to read remote file {path}: {stderr}")
+    return result.stdout
+
+
+def remote_write_file(path: str, content: str) -> None:
+    """Write content to a file on the remote host atomically.
+
+    Uses temp file + mv for atomic write, matching local behavior.
+
+    Args:
+        path: Absolute file path on remote host
+        content: Content to write
+
+    Raises:
+        IOError: If write fails
+    """
+    # Escape content for shell, use heredoc via stdin
+    ssh_cmd = _ssh_base_cmd()
+    # Atomic write: write to temp file, then rename
+    remote_script = f"tmpf=$(mktemp {path}.tmp.XXXXXX) && cat > \"$tmpf\" && mv \"$tmpf\" {path}"
+    ssh_cmd.append(remote_script)
+
+    logger.debug("SSH write: %s (%d bytes)", path, len(content))
+    result = subprocess.run(
+        ssh_cmd,
+        input=content,
+        capture_output=True,
+        text=True,
+        timeout=SUBPROCESS_TIMEOUT,
+    )
+    if result.returncode != 0:
+        raise IOError(f"Failed to write remote file {path}: {result.stderr.strip()}")
+
+
+def remote_file_exists(path: str) -> bool:
+    """Check if a file exists on the remote host.
+
+    Args:
+        path: Absolute file path on remote host
+
+    Returns:
+        True if file exists
+    """
+    result = remote_exec(f"test -f {path} && echo yes || echo no")
+    return result.stdout.strip() == "yes"
+
+
+def run_command(args: list[str], timeout: int = SUBPROCESS_TIMEOUT) -> subprocess.CompletedProcess:
+    """Execute a command locally or remotely based on REMOTE_MODE.
+
+    Args:
+        args: Command and arguments as list
+        timeout: Command timeout in seconds
+
+    Returns:
+        CompletedProcess with stdout/stderr
+    """
+    if REMOTE_MODE:
+        # Join args into a shell command for SSH
+        # Quote arguments that contain spaces
+        quoted = []
+        for a in args:
+            if " " in a or "'" in a or '"' in a:
+                quoted.append(f"'{a}'")
+            else:
+                quoted.append(a)
+        return remote_exec(" ".join(quoted), timeout=timeout)
+    else:
+        return subprocess.run(
+            args,
+            capture_output=True,
+            text=True,
+            timeout=timeout,
+        )

haproxy_mcp/tools/certificates.py

@@ -1,7 +1,6 @@
 """Certificate management tools for HAProxy MCP Server."""
 
 import os
-import subprocess
 from datetime import datetime
 from typing import Annotated
 
@@ -13,6 +12,7 @@ from ..config import (
     CERTS_DIR,
     CERTS_DIR_CONTAINER,
     ACME_HOME,
+    REMOTE_MODE,
 )
 from ..exceptions import HaproxyError
 from ..validation import validate_domain
@@ -21,58 +21,48 @@ from ..file_ops import (
     load_certs_config,
     add_cert_to_config,
     remove_cert_from_config,
+    _read_file,
 )
+from ..ssh_ops import run_command, remote_file_exists
 
 # acme.sh script path (derived from ACME_HOME)
-ACME_SH = os.path.join(ACME_HOME, "acme.sh")
+ACME_SH = f"{ACME_HOME}/acme.sh"
 
 # Longer timeout for certificate operations (ACME can be slow)
 CERT_TIMEOUT = 120
 
 
+def _file_exists(path: str) -> bool:
+    """Check file existence locally or remotely."""
+    if REMOTE_MODE:
+        return remote_file_exists(path)
+    return os.path.exists(path)
+
+
 def get_pem_paths(domain: str) -> tuple[str, str]:
-    """Get host and container PEM paths for a domain.
+    """Get host and container PEM paths for a domain."""
-
-    Args:
-        domain: Domain name
-
-    Returns:
-        Tuple of (host_path, container_path)
-    """
     return (
-        os.path.join(CERTS_DIR, f"{domain}.pem"),
+        f"{CERTS_DIR}/{domain}.pem",
-        os.path.join(CERTS_DIR_CONTAINER, f"{domain}.pem")
+        f"{CERTS_DIR_CONTAINER}/{domain}.pem",
     )
 
 
 def load_cert_to_haproxy(domain: str) -> tuple[bool, str]:
-    """Load a certificate into HAProxy via Runtime API (zero-downtime).
+    """Load a certificate into HAProxy via Runtime API (zero-downtime)."""
-
-    Args:
-        domain: Domain name
-
-    Returns:
-        Tuple of (success, message)
-    """
     host_path, container_path = get_pem_paths(domain)
 
-    if not os.path.exists(host_path):
+    if not _file_exists(host_path):
         return False, f"PEM file not found: {host_path}"
 
     try:
-        # Read PEM content
+        pem_content = _read_file(host_path)
-        with open(host_path, "r", encoding="utf-8") as f:
-            pem_content = f.read()
 
-        # Check if cert already loaded
         result = haproxy_cmd("show ssl cert")
         if container_path in result:
-            # Update existing cert
             haproxy_cmd(f"set ssl cert {container_path} <<\n{pem_content}\n")
             haproxy_cmd(f"commit ssl cert {container_path}")
             return True, "updated"
         else:
-            # Add new cert
             haproxy_cmd(f"new ssl cert {container_path}")
             haproxy_cmd(f"set ssl cert {container_path} <<\n{pem_content}\n")
             haproxy_cmd(f"commit ssl cert {container_path}")
@@ -87,40 +77,24 @@ def load_cert_to_haproxy(domain: str) -> tuple[bool, str]:
 
 
 def unload_cert_from_haproxy(domain: str) -> tuple[bool, str]:
-    """Unload a certificate from HAProxy via Runtime API.
+    """Unload a certificate from HAProxy via Runtime API."""
-
-    Args:
-        domain: Domain name
-
-    Returns:
-        Tuple of (success, message)
-    """
     _, container_path = get_pem_paths(domain)
 
     try:
-        # Check if cert is loaded
         result = haproxy_cmd("show ssl cert")
         if container_path not in result:
             return True, "not loaded"
-
-        # Delete from HAProxy runtime
         haproxy_cmd(f"del ssl cert {container_path}")
         return True, "unloaded"
-
     except HaproxyError as e:
         logger.error("HAProxy error unloading certificate %s: %s", domain, e)
         return False, str(e)
 
 
 def restore_certificates() -> int:
-    """Restore all certificates from config to HAProxy on startup.
+    """Restore all certificates from config to HAProxy on startup."""
-
-    Returns:
-        Number of certificates restored
-    """
     domains = load_certs_config()
     restored = 0
-
     for domain in domains:
         success, msg = load_cert_to_haproxy(domain)
         if success:
@@ -128,23 +102,13 @@ def restore_certificates() -> int:
             logger.debug("Certificate %s: %s", domain, msg)
         else:
             logger.warning("Failed to restore certificate %s: %s", domain, msg)
-
     return restored
 
 
-# =============================================================================
-# Implementation functions (module-level)
-# =============================================================================
-
-
 def _haproxy_list_certs_impl() -> str:
     """Implementation of haproxy_list_certs."""
     try:
-        result = subprocess.run(
+        result = run_command([ACME_SH, "--list"], timeout=SUBPROCESS_TIMEOUT)
-            [ACME_SH, "--list"],
-            capture_output=True, text=True, timeout=SUBPROCESS_TIMEOUT,
-            env={**os.environ, "HOME": os.path.expanduser("~")}
-        )
         if result.returncode != 0:
             return f"Error: {result.stderr}"
 
@@ -152,16 +116,14 @@ def _haproxy_list_certs_impl() -> str:
         if len(lines) <= 1:
             return "No certificates found"
 
-        # Get HAProxy loaded certs
         try:
             haproxy_certs = haproxy_cmd("show ssl cert")
         except HaproxyError as e:
             logger.debug("Could not get HAProxy certs: %s", e)
             haproxy_certs = ""
 
-        # Parse and format output
         certs = []
-        for line in lines[1:]:  # Skip header
+        for line in lines[1:]:
             parts = line.split()
             if len(parts) >= 4:
                 domain = parts[0]
@@ -178,11 +140,10 @@ def _haproxy_list_certs_impl() -> str:
                         else:
                             renew = part
 
-                # Check deployment status
                 host_path, container_path = get_pem_paths(domain)
                 if container_path in haproxy_certs:
                     status = "loaded"
-                elif os.path.exists(host_path):
+                elif _file_exists(host_path):
                     status = "file exists (not loaded)"
                 else:
                     status = "not deployed"
@@ -190,15 +151,12 @@ def _haproxy_list_certs_impl() -> str:
                 certs.append(f"• {domain} ({ca})\n  Created: {created}\n  Renew: {renew}\n  Status: {status}")
 
         return "\n\n".join(certs) if certs else "No certificates found"
-    except subprocess.TimeoutExpired:
+    except TimeoutError:
         return "Error: Command timed out"
     except FileNotFoundError:
         return "Error: acme.sh not found"
-    except subprocess.SubprocessError as e:
-        logger.error("Subprocess error listing certificates: %s", e)
-        return f"Error: {e}"
     except OSError as e:
-        logger.error("OS error listing certificates: %s", e)
+        logger.error("Error listing certificates: %s", e)
         return f"Error: {e}"
 
 
@@ -208,24 +166,26 @@ def _haproxy_cert_info_impl(domain: str) -> str:
         return "Error: Invalid domain format"
 
     host_path, container_path = get_pem_paths(domain)
-    if not os.path.exists(host_path):
+    if not _file_exists(host_path):
         return f"Error: Certificate not found for {domain}"
 
     try:
-        # Use openssl to get certificate info
+        result = run_command(
-        result = subprocess.run(
             ["openssl", "x509", "-in", host_path, "-noout",
              "-subject", "-issuer", "-dates", "-ext", "subjectAltName"],
-            capture_output=True, text=True, timeout=SUBPROCESS_TIMEOUT
+            timeout=SUBPROCESS_TIMEOUT,
         )
         if result.returncode != 0:
             return f"Error reading certificate: {result.stderr}"
 
-        # Get file info
+        # Get file modification time
-        stat = os.stat(host_path)
+        stat_result = run_command(["stat", "-c", "%Y", host_path])
-        modified = datetime.fromtimestamp(stat.st_mtime).strftime("%Y-%m-%d %H:%M:%S")
+        if stat_result.returncode == 0:
+            ts = int(stat_result.stdout.strip())
+            modified = datetime.fromtimestamp(ts).strftime("%Y-%m-%d %H:%M:%S")
+        else:
+            modified = "unknown"
 
-        # Check HAProxy status
         try:
             haproxy_certs = haproxy_cmd("show ssl cert")
             loaded = "Yes" if container_path in haproxy_certs else "No"
@@ -242,9 +202,9 @@ def _haproxy_cert_info_impl(domain: str) -> str:
             result.stdout.strip()
         ]
         return "\n".join(info)
-    except subprocess.TimeoutExpired:
+    except TimeoutError:
         return "Error: Command timed out"
-    except (subprocess.SubprocessError, OSError) as e:
+    except OSError as e:
         logger.error("Error getting certificate info for %s: %s", domain, e)
         return f"Error: {e}"
 
@@ -254,62 +214,29 @@ def _haproxy_issue_cert_impl(domain: str, wildcard: bool) -> str:
     if not validate_domain(domain):
         return "Error: Invalid domain format"
 
-    # Check if CF_Token is available
+    cert_dir = f"{ACME_HOME}/{domain}_ecc"
-    if not os.environ.get("CF_Token"):
+    if _file_exists(cert_dir):
-        secrets_file = os.path.expanduser("~/.secrets/cloudflare.ini")
-        if os.path.exists(secrets_file):
-            try:
-                with open(secrets_file) as f:
-                    for line in f:
-                        if "=" in line and "token" in line.lower():
-                            token = line.split("=", 1)[1].strip().strip('"').strip("'")
-                            os.environ["CF_Token"] = token
-                            break
-            except (IOError, OSError) as e:
-                logger.warning("Failed to read Cloudflare token: %s", e)
-
-        if not os.environ.get("CF_Token"):
-            return "Error: CF_Token not set. Export CF_Token or add to ~/.secrets/cloudflare.ini"
-
-    # Check if certificate already exists
-    cert_dir = os.path.join(ACME_HOME, f"{domain}_ecc")
-    if os.path.exists(cert_dir):
         return f"Error: Certificate for {domain} already exists. Use haproxy_renew_cert to renew."
 
-    # Build acme.sh command (without reload - we'll do it via Runtime API)
     host_path, _ = get_pem_paths(domain)
-
-    # Create PEM after issuance
     install_cmd = f"cat {ACME_HOME}/{domain}_ecc/fullchain.cer {ACME_HOME}/{domain}_ecc/{domain}.key > {host_path}"
 
-    cmd = [
+    cmd = [ACME_SH, "--issue", "--dns", "dns_cf", "-d", domain]
-        ACME_SH, "--issue",
-        "--dns", "dns_cf",
-        "-d", domain
-    ]
-
     if wildcard:
         cmd.extend(["-d", f"*.{domain}"])
-
     cmd.extend(["--reloadcmd", install_cmd])
 
     try:
         logger.info("Issuing certificate for %s", domain)
-        result = subprocess.run(
+        result = run_command(cmd, timeout=CERT_TIMEOUT)
-            cmd,
-            capture_output=True, text=True, timeout=CERT_TIMEOUT,
-            env={**os.environ, "HOME": os.path.expanduser("~")}
-        )
 
         if result.returncode != 0:
             error_msg = result.stderr or result.stdout
             return f"Error issuing certificate:\n{error_msg}"
 
-        # Load into HAProxy via Runtime API (zero-downtime)
+        if _file_exists(host_path):
-        if os.path.exists(host_path):
             success, msg = load_cert_to_haproxy(domain)
             if success:
-                # Save to config for persistence
                 add_cert_to_config(domain)
                 return f"Certificate issued and loaded for {domain} ({msg})"
             else:
@@ -317,9 +244,9 @@ def _haproxy_issue_cert_impl(domain: str, wildcard: bool) -> str:
         else:
             return f"Certificate issued but PEM file not created. Check {host_path}"
 
-    except subprocess.TimeoutExpired:
+    except TimeoutError:
         return f"Error: Certificate issuance timed out after {CERT_TIMEOUT}s"
-    except (subprocess.SubprocessError, OSError) as e:
+    except OSError as e:
         logger.error("Error issuing certificate for %s: %s", domain, e)
         return f"Error: {e}"
 
@@ -329,8 +256,8 @@ def _haproxy_renew_cert_impl(domain: str, force: bool) -> str:
     if not validate_domain(domain):
         return "Error: Invalid domain format"
 
-    cert_dir = os.path.join(ACME_HOME, f"{domain}_ecc")
+    cert_dir = f"{ACME_HOME}/{domain}_ecc"
-    if not os.path.exists(cert_dir):
+    if not _file_exists(cert_dir):
         return f"Error: No certificate found for {domain}. Use haproxy_issue_cert first."
 
     cmd = [ACME_SH, "--renew", "-d", domain]
@@ -339,11 +266,7 @@ def _haproxy_renew_cert_impl(domain: str, force: bool) -> str:
 
     try:
         logger.info("Renewing certificate for %s", domain)
-        result = subprocess.run(
+        result = run_command(cmd, timeout=CERT_TIMEOUT)
-            cmd,
-            capture_output=True, text=True, timeout=CERT_TIMEOUT,
-            env={**os.environ, "HOME": os.path.expanduser("~")}
-        )
 
         output = result.stdout + result.stderr
 
@@ -351,10 +274,8 @@ def _haproxy_renew_cert_impl(domain: str, force: bool) -> str:
             return f"Certificate for {domain} not due for renewal. Use force=True to force renewal."
 
         if "Cert success" in output or result.returncode == 0:
-            # Reload into HAProxy via Runtime API
             success, msg = load_cert_to_haproxy(domain)
             if success:
-                # Ensure in config
                 add_cert_to_config(domain)
                 return f"Certificate renewed and reloaded for {domain} ({msg})"
             else:
@@ -362,11 +283,11 @@ def _haproxy_renew_cert_impl(domain: str, force: bool) -> str:
         else:
             return f"Error renewing certificate:\n{output}"
 
-    except subprocess.TimeoutExpired:
+    except TimeoutError:
         return f"Error: Certificate renewal timed out after {CERT_TIMEOUT}s"
     except FileNotFoundError:
         return "Error: acme.sh not found"
-    except (subprocess.SubprocessError, OSError) as e:
+    except OSError as e:
         logger.error("Error renewing certificate for %s: %s", domain, e)
         return f"Error: {e}"
 
@@ -375,19 +296,12 @@ def _haproxy_renew_all_certs_impl() -> str:
     """Implementation of haproxy_renew_all_certs."""
     try:
         logger.info("Running certificate renewal cron")
-        result = subprocess.run(
+        result = run_command([ACME_SH, "--cron"], timeout=CERT_TIMEOUT * 3)
-            [ACME_SH, "--cron"],
-            capture_output=True, text=True, timeout=CERT_TIMEOUT * 3,
-            env={**os.environ, "HOME": os.path.expanduser("~")}
-        )
 
         output = result.stdout + result.stderr
-
-        # Count renewals
         renewed = output.count("Cert success")
         skipped = output.count("Skip")
 
-        # Reload any renewed certs into HAProxy
         if renewed > 0:
             domains = load_certs_config()
             reloaded = 0
@@ -403,11 +317,11 @@ def _haproxy_renew_all_certs_impl() -> str:
         else:
             return "Renewal check completed"
 
-    except subprocess.TimeoutExpired:
+    except TimeoutError:
         return "Error: Renewal cron timed out"
     except FileNotFoundError:
         return "Error: acme.sh not found"
-    except (subprocess.SubprocessError, OSError) as e:
+    except OSError as e:
         logger.error("Error running certificate renewal cron: %s", e)
         return f"Error: {e}"
 
@@ -417,46 +331,44 @@ def _haproxy_delete_cert_impl(domain: str) -> str:
     if not validate_domain(domain):
         return "Error: Invalid domain format"
 
-    cert_dir = os.path.join(ACME_HOME, f"{domain}_ecc")
+    cert_dir = f"{ACME_HOME}/{domain}_ecc"
     host_path, _ = get_pem_paths(domain)
 
-    if not os.path.exists(cert_dir) and not os.path.exists(host_path):
+    if not _file_exists(cert_dir) and not _file_exists(host_path):
         return f"Error: No certificate found for {domain}"
 
     errors = []
     deleted = []
 
-    # Unload from HAProxy first (zero-downtime)
     success, msg = unload_cert_from_haproxy(domain)
     if success:
         deleted.append(f"HAProxy ({msg})")
     else:
         errors.append(f"HAProxy unload: {msg}")
 
-    # Remove from acme.sh
+    if _file_exists(cert_dir):
-    if os.path.exists(cert_dir):
         try:
-            result = subprocess.run(
+            result = run_command(
                 [ACME_SH, "--remove", "-d", domain],
-                capture_output=True, text=True, timeout=SUBPROCESS_TIMEOUT,
+                timeout=SUBPROCESS_TIMEOUT,
-                env={**os.environ, "HOME": os.path.expanduser("~")}
             )
             if result.returncode == 0:
                 deleted.append("acme.sh")
             else:
                 errors.append(f"acme.sh: {result.stderr}")
-        except (subprocess.TimeoutExpired, subprocess.SubprocessError, OSError) as e:
+        except (TimeoutError, OSError) as e:
             errors.append(f"acme.sh: {e}")
 
-    # Remove PEM file
+    if _file_exists(host_path):
-    if os.path.exists(host_path):
         try:
-            os.remove(host_path)
+            result = run_command(["rm", "-f", host_path])
+            if result.returncode == 0:
                 deleted.append("PEM file")
+            else:
+                errors.append(f"PEM file: {result.stderr}")
         except OSError as e:
             errors.append(f"PEM file: {e}")
 
-    # Remove from config
     remove_cert_from_config(domain)
 
     result_parts = []
@@ -474,7 +386,7 @@ def _haproxy_load_cert_impl(domain: str) -> str:
         return "Error: Invalid domain format"
 
     host_path, _ = get_pem_paths(domain)
-    if not os.path.exists(host_path):
+    if not _file_exists(host_path):
         return f"Error: PEM file not found: {host_path}"
 
     success, msg = load_cert_to_haproxy(domain)
@@ -485,11 +397,6 @@ def _haproxy_load_cert_impl(domain: str) -> str:
         return f"Error loading certificate: {msg}"
 
 
-# =============================================================================
-# MCP Tool Registration
-# =============================================================================
-
-
 def register_certificate_tools(mcp):
     """Register certificate management tools with MCP server."""
 

haproxy_mcp/tools/configuration.py

@@ -1,6 +1,5 @@
 """Configuration management tools for HAProxy MCP Server."""
 
-import subprocess
 import time
 
 from ..config import (
@@ -18,6 +17,7 @@ from ..file_ops import (
     get_domain_backend,
     get_backend_and_prefix,
 )
+from ..ssh_ops import run_command
 
 
 def restore_servers_from_config() -> int:
@@ -167,17 +167,17 @@ def register_config_tools(mcp):
             Validation result or error details
         """
         try:
-            result = subprocess.run(
+            result = run_command(
                 ["podman", "exec", HAPROXY_CONTAINER, "haproxy", "-c", "-f", "/usr/local/etc/haproxy/haproxy.cfg"],
-                capture_output=True, text=True, timeout=SUBPROCESS_TIMEOUT
+                timeout=SUBPROCESS_TIMEOUT,
             )
             if result.returncode == 0:
                 return "Configuration is valid"
             return f"Configuration errors:\n{result.stderr}"
-        except subprocess.TimeoutExpired:
+        except TimeoutError:
             return f"Error: Command timed out after {SUBPROCESS_TIMEOUT} seconds"
         except FileNotFoundError:
-            return "Error: podman command not found"
+            return "Error: ssh/podman command not found"
         except OSError as e:
             return f"Error: OS error: {e}"
 

haproxy_mcp/tools/domains.py

@@ -1,8 +1,6 @@
 """Domain management tools for HAProxy MCP Server."""
 
-import fcntl
 import os
-import subprocess
 from typing import Annotated, Optional
 
 from pydantic import Field
@@ -15,8 +13,10 @@ from ..config import (
     MAX_SLOTS,
     SUBPROCESS_TIMEOUT,
     CERTS_DIR,
+    REMOTE_MODE,
     logger,
 )
+from ..ssh_ops import run_command, remote_file_exists
 from ..exceptions import HaproxyError
 from ..validation import validate_domain, validate_ip, validate_port_int
 from ..haproxy_client import haproxy_cmd
@@ -115,6 +115,13 @@ def _rollback_domain_addition(
         logger.error("Failed to rollback map file after HAProxy error")
 
 
+def _file_exists(path: str) -> bool:
+    """Check file existence locally or remotely."""
+    if REMOTE_MODE:
+        return remote_file_exists(path)
+    return os.path.exists(path)
+
+
 def check_certificate_coverage(domain: str) -> tuple[bool, str]:
     """Check if a domain is covered by an existing certificate.
 
@@ -124,34 +131,35 @@ def check_certificate_coverage(domain: str) -> tuple[bool, str]:
     Returns:
         Tuple of (is_covered, certificate_name or message)
     """
-    if not os.path.isdir(CERTS_DIR):
+    if REMOTE_MODE:
+        dir_check = run_command(["test", "-d", CERTS_DIR])
+        if dir_check.returncode != 0:
+            return False, "Certificate directory not found"
+    elif not os.path.isdir(CERTS_DIR):
         return False, "Certificate directory not found"
 
     # Check for exact match first
-    exact_pem = os.path.join(CERTS_DIR, f"{domain}.pem")
+    exact_pem = f"{CERTS_DIR}/{domain}.pem"
-    if os.path.exists(exact_pem):
+    if _file_exists(exact_pem):
         return True, domain
 
     # Check for wildcard coverage (e.g., api.example.com covered by *.example.com)
     parts = domain.split(".")
     if len(parts) >= 2:
-        # Try parent domain (example.com for api.example.com)
         parent_domain = ".".join(parts[1:])
-        parent_pem = os.path.join(CERTS_DIR, f"{parent_domain}.pem")
+        parent_pem = f"{CERTS_DIR}/{parent_domain}.pem"
 
-        if os.path.exists(parent_pem):
+        if _file_exists(parent_pem):
-            # Verify the certificate has wildcard SAN
             try:
-                result = subprocess.run(
+                result = run_command(
                     ["openssl", "x509", "-in", parent_pem, "-noout", "-ext", "subjectAltName"],
-                    capture_output=True, text=True, timeout=SUBPROCESS_TIMEOUT
+                    timeout=SUBPROCESS_TIMEOUT,
                 )
                 if result.returncode == 0:
-                    # Check if wildcard covers this domain
                     wildcard = f"*.{parent_domain}"
                     if wildcard in result.stdout:
                         return True, f"{parent_domain} (wildcard)"
-            except (subprocess.TimeoutExpired, OSError):
+            except (TimeoutError, OSError):
                 pass
 
     return False, "No matching certificate"
@@ -235,10 +243,8 @@ def register_domain_tools(mcp):
             return "Error: Cannot specify both ip and share_with (shared domains use existing servers)"
 
         # Use file locking for the entire pool allocation operation
-        lock_path = f"{MAP_FILE}.lock"
+        from ..file_ops import file_lock
-        with open(lock_path, 'w') as lock_file:
+        with file_lock(f"{MAP_FILE}.lock"):
-            fcntl.flock(lock_file.fileno(), fcntl.LOCK_EX)
-            try:
             # Read map contents once for both existence check and pool lookup
             entries = get_map_contents()
 
@@ -323,8 +329,6 @@ def register_domain_tools(mcp):
 
             except HaproxyError as e:
                 return f"Error: {e}"
-            finally:
-                fcntl.flock(lock_file.fileno(), fcntl.LOCK_UN)
 
     @mcp.tool()
     def haproxy_remove_domain(

haproxy_mcp/tools/health.py

@@ -1,7 +1,6 @@
 """Health check tools for HAProxy MCP Server."""
 
 import json
-import os
 import subprocess
 import time
 from typing import Annotated, Any
@@ -18,6 +17,8 @@ from ..validation import validate_domain, validate_backend_name
 from ..haproxy_client import haproxy_cmd
 from ..file_ops import get_backend_and_prefix
 from ..utils import parse_stat_csv, parse_servers_state
+from ..ssh_ops import run_command, remote_file_exists
+from ..config import REMOTE_MODE
 
 
 def register_health_tools(mcp):
@@ -65,9 +66,9 @@ def register_health_tools(mcp):
 
         # Check container status
         try:
-            container_result = subprocess.run(
+            container_result = run_command(
                 ["podman", "inspect", "--format", "{{.State.Status}}", HAPROXY_CONTAINER],
-                capture_output=True, text=True, timeout=5
+                timeout=5,
             )
             if container_result.returncode == 0:
                 container_status = container_result.stdout.strip()
@@ -88,7 +89,8 @@ def register_health_tools(mcp):
         files_ok = True
         file_status: dict[str, str] = {}
         for name, path in [("map_file", MAP_FILE), ("servers_file", SERVERS_FILE)]:
-            if os.path.exists(path):
+            exists = remote_file_exists(path) if REMOTE_MODE else __import__('os').path.exists(path)
+            if exists:
                 file_status[name] = "ok"
             else:
                 file_status[name] = "missing"

k8s/deployment.yaml

@@ -32,8 +32,20 @@ spec:
               value: "10.253.100.107"
             - name: HAPROXY_PORT
               value: "9999"
+            - name: SSH_HOST
+              value: "10.253.100.107"
+            - name: SSH_USER
+              value: "root"
+            - name: SSH_KEY
+              value: "/root/.ssh/id_rsa"
+            - name: SSH_PORT
+              value: "22"
             - name: LOG_LEVEL
               value: "INFO"
+          volumeMounts:
+            - name: ssh-key
+              mountPath: /root/.ssh
+              readOnly: true
           readinessProbe:
             tcpSocket:
               port: 8000
@@ -51,3 +63,8 @@ spec:
             limits:
               memory: "256Mi"
               cpu: "500m"
+      volumes:
+        - name: ssh-key
+          secret:
+            secretName: haproxy-ssh-key
+            defaultMode: 0600