# Beszel Agent Helm Chart

A Kubernetes Helm chart for deploying [Beszel Agent](https://www.beszel.dev/) - a lightweight monitoring agent that collects system metrics and sends them to a central Beszel Hub.

## Overview

This Helm chart simplifies the deployment of Beszel Agent in Kubernetes environments. By default, it deploys as a DaemonSet to run one agent on each node in the cluster. The agent monitors node-level system resources (CPU, memory, disk, network, temperature, GPU, etc.) and provides detailed metrics to the Beszel Hub for centralized monitoring and alerting.

## Features

- ✅ DaemonSet deployment by default (one agent per node)
- ✅ GPU support via NVIDIA runtime (optional)
- ✅ Additional filesystem mounting for multi-disk monitoring
- ✅ Flexible deployment as DaemonSet or single Deployment
- ✅ Environment variable configuration for agent authentication
- ✅ Host network support for detailed network monitoring
- ✅ Automatic handling of tainted nodes via tolerations

## Prerequisites

- Kubernetes 1.19+
- Helm 3.0+
- Beszel Hub instance running and accessible
- SSH public key for agent authentication

## What Gets Monitored

In Kubernetes environments, the Beszel agent monitors **node-level metrics**:

- **CPU usage** - Node CPU utilization and per-core stats
- **Memory usage** - Node memory, swap, and ZFS ARC
- **Disk usage** - Node filesystem usage and I/O statistics
- **Network usage** - Node network traffic (requires `hostNetwork: true`)
- **Load average** - System load averages
- **Temperature** - Node hardware sensors
- **GPU usage/power** - NVIDIA, AMD, and Intel GPUs (with appropriate image)
- **Battery** - Node battery status (if applicable)
- **S.M.A.T.** - Disk health monitoring

**Note**: The agent does **not** monitor individual Kubernetes pods or containers. For pod/container metrics, use Kubernetes metrics-server or monitoring tools like Prometheus.

## Quick Start

### 1. Install the OCI Chart

```bash
helm install beszel-agent oci://ghcr.io/henrygd/beszel-charts/beszel-agent \
  --set env.KEY="ssh-ed25519 AAAA... your-public-key" \
  --set env.TOKEN="your-token-value" \
  --set env.HUB_URL="http://beszel-hub:8090"
```

Or with custom values:

```bash
helm install beszel-agent oci://ghcr.io/henrygd/beszel-charts/beszel-agent -f custom-values.yaml
```

### 2. Verify the Agent is Running

```bash
kubectl get pods -l app.kubernetes.io/name=beszel-agent
kubectl logs -l app.kubernetes.io/name=beszel-agent
```

## Configuration

### Basic Configuration

Essential parameters to configure:

| Parameter | Default | Description |
|-----------|---------|-------------|
| `daemonset.enabled` | `true` | Deploy as DaemonSet (one pod per node) |
| `env.KEY` | Required* | SSH public key for Hub authentication (*unless using existingSecret) |
| `env.TOKEN` | Empty | Authentication token (optional) |
| `env.HUB_URL` | Empty | Hub URL (e.g., http://beszel-hub:8090) |
| `env.PORT` | `45876` | Port the agent listens on |
| `secret.existingSecret` | Empty | Name of an existing Kubernetes Secret to use |
| `secret.sshKey` | `ssh-key` | Key name in the secret for the SSH public key |
| `secret.tokenKey` | `token` | Key name in the secret for the authentication token |
| `image.repository` | `henrygd/beszel-agent` | Container image |
| `image.tag` | Chart AppVersion (0.18.7) | Image version |
| `hostNetwork` | `false` | Use host network for network monitoring |
| `tolerations` | Allows all taints | Tolerations for running on tainted nodes |

### Minimal Configuration

```bash
helm install beszel-agent ./beszel-agent \
  --set env.KEY="ssh-ed25519 AAAA... your-public-key" \
  --set env.TOKEN="your-token-value" \
  --set env.HUB_URL="http://beszel-hub:8090"
```

### Standard Configuration

```yaml
# values.yaml
image:
  repository: henrygd/beszel-agent
  tag: ""  # Uses chart appVersion

env:
  PORT: "45876"
  KEY: "ssh-ed25519 AAAA... your-public-key"
  TOKEN: "your-token-value"
  HUB_URL: "http://beszel-hub:8090"

# Use host network for accurate network monitoring
hostNetwork: false
```

### GPU Support (NVIDIA)

For systems with NVIDIA GPUs, use the special GPU-enabled image:

```yaml
image:
  repository: henrygd/beszel-agent-nvidia

# Enable NVIDIA runtime
gpuRuntime: nvidia

env:
  PORT: "45876"
  KEY: "ssh-ed25519 AAAA... your-public-key"
  TOKEN: "your-token-value"
  HUB_URL: "http://beszel-hub:8090"
  NVIDIA_VISIBLE_DEVICES: "all"
  NVIDIA_DRIVER_CAPABILITIES: "compute,video,utility"
```

**Note**: The GPU image (`henrygd/beszel-agent-nvidia`) is specifically for monitoring NVIDIA GPUs on the node. It does not provide container-level GPU metrics.

Or via CLI:

```bash
helm install beszel-agent ./beszel-agent \
  --set image.repository=henrygd/beszel-agent-nvidia \
  --set gpuRuntime=nvidia \
  --set env.NVIDIA_VISIBLE_DEVICES=all \
  --set env.NVIDIA_DRIVER_CAPABILITIES="compute,video,utility" \
  --set env.KEY="ssh-ed25519 AAAA... your-public-key" \
  --set env.TOKEN="your-token-value" \
  --set env.HUB_URL="http://beszel-hub:8090"
```

### Monitor Additional Filesystems

To monitor additional disks or partitions:

```yaml
volumes:
  - name: extra-filesystems
    hostPath:
      path: /mnt/disk/.beszel
      type: DirectoryOrCreate

volumeMounts:
  - name: extra-filesystems
    mountPath: /extra-filesystems
    readOnly: true

env:
  PORT: "45876"
  KEY: "ssh-ed25519 AAAA... your-public-key"
  TOKEN: "your-token-value"
  HUB_URL: "http://beszel-hub:8090"
```

### Advanced Configuration

#### Resource Limits

```yaml
resources:
  limits:
    cpu: 500m
    memory: 256Mi
  requests:
    cpu: 100m
    memory: 128Mi
```

#### Node Selection

Run agents on specific nodes:

```yaml
nodeSelector:
  monitoring: "true"

tolerations:
  - key: monitoring
    operator: Equal
    value: "true"
    effect: NoSchedule

affinity:
  podAntiAffinity:
    preferredDuringSchedulingIgnoredDuringExecution:
      - weight: 100
        podAffinityTerm:
          labelSelector:
            matchExpressions:
              - key: app.kubernetes.io/name
                operator: In
                values:
                  - beszel-agent
          topologyKey: kubernetes.io/hostname
```

#### Host Network

For detailed network statistics, enable host network mode:

```yaml
hostNetwork: true

env:
  PORT: "45876"
  KEY: "ssh-ed25519 AAAA... your-public-key"
  TOKEN: "your-token-value"
  HUB_URL: "http://beszel-hub:8090"
```

**Note**: When `hostNetwork: true`, the agent can monitor the node's actual network interfaces. When `false`, it only sees the pod's network namespace.

#### DaemonSet Mode

By default, the agent is deployed as a DaemonSet, running one pod on each cluster node:

```yaml
daemonset:
  enabled: true  # Default - one agent per node

# Or disable for single Deployment deployment
daemonset:
  enabled: false
replicaCount: 1
```

#### Tolerations

By default, tolerations are set to allow agents to run on all nodes, including tainted ones:

```yaml
tolerations:
  - operator: Exists
    effect: NoSchedule
  - operator: Exists
    effect: NoExecute
```

To restrict agents to specific nodes:

```yaml
tolerations: []
nodeSelector:
  monitoring: "true"
```

### Using Existing Secrets

The chart supports referencing an existing Kubernetes Secret instead of having the chart create one. This is useful when:

- You want to manage secrets externally (e.g., with a secret operator, external secret manager, or GitOps)
- You want to share a single secret across multiple deployments
- You prefer not to store sensitive values in Helm values

```yaml
# Create the secret manually
apiVersion: v1
kind: Secret
metadata:
  name: my-beszel-secret
type: Opaque
data:
  ssh-key: c3NoLWVkMjU1IDEgQUFBQU...  # base64 encoded SSH public key
  token: dG9rZW4tdmFsdWU=              # base64 encoded token (optional)
```

Then reference it in your values:

```yaml
secret:
  existingSecret: my-beszel-secret
  sshKey: ssh-key      # key name in the secret (default: ssh-key)
  tokenKey: token      # key name in the secret (default: token)

env:
  HUB_URL: "http://beszel-hub:8090"
```

**Note**: When using `existingSecret`, do not set `env.KEY` or `env.TOKEN` - the chart will use the values from the existing secret instead.

You can also use different key names if your secret uses non-standard keys:

```yaml
secret:
  existingSecret: my-beszel-secret
  sshKey: public-key     # custom key name
  tokenKey: auth-token  # custom key name
```

## Deployment Examples

### Full Cluster Monitoring (DaemonSet - Default)

```bash
helm install beszel-agent ./beszel-agent \
  --set env.KEY="ssh-ed25519 AAAA... your-public-key" \
  --set env.TOKEN="your-token-value" \
  --set env.HUB_URL="http://beszel-hub:8090"
```

This deploys one agent on every node in the cluster automatically.

### Single Agent Deployment (Non-DaemonSet)

```yaml
# values.yaml
daemonset:
  enabled: false

replicaCount: 1

env:
  PORT: "45876"
  KEY: "ssh-ed25519 AAAA... your-public-key"
  TOKEN: "your-token-value"
  HUB_URL: "http://beszel-hub:8090"
```

Or via CLI:

```bash
helm install beszel-agent ./beszel-agent \
  --set daemonset.enabled=false \
  --set replicaCount=1 \
  --set env.KEY="ssh-ed25519 AAAA... your-public-key" \
  --set env.TOKEN="your-token-value" \
  --set env.HUB_URL="http://beszel-hub:8090"
```

### Network Monitoring with Host Network

```yaml
hostNetwork: true

env:
  PORT: "45876"
  KEY: "ssh-ed25519 AAAA... your-public-key"
  TOKEN: "your-token-value"
  HUB_URL: "http://beszel-hub:8090"

podSecurityContext:
  hostNetwork: true
```

## Managing the Agent

### Check Agent Status

```bash
# List agent pods
kubectl get pods -l app.kubernetes.io/name=beszel-agent

# View agent logs
kubectl logs -l app.kubernetes.io/name=beszel-agent -f

# Describe a specific pod
kubectl describe pod <pod-name>
```

### Update Configuration

```bash
# Update the SSH key
helm upgrade beszel-agent ./beszel-agent \
  --set env.KEY="ssh-ed25519 AAAA... your-public-key" \
  --set env.TOKEN="your-token-value" \
  --set env.HUB_URL="http://beszel-hub:8090"

# Change image version
helm upgrade beszel-agent ./beszel-agent \
  --set image.tag="0.18.7"
```

### Restart All Agents

```bash
# For DaemonSet (default)
kubectl rollout restart daemonset beszel-agent

# For Deployment (if daemonset.enabled=false)
kubectl rollout restart deployment beszel-agent
```

### Uninstall

```bash
helm uninstall beszel-agent
```

### View Helm Release History

```bash
helm history beszel-agent
helm rollback beszel-agent 1  # Rollback to previous version
```

## Environment Variables

| Variable | Default | Description |
|----------|---------|-------------|
| `PORT` | `45876` | Port the agent listens on |
| `KEY` | Required | SSH public key for Hub authentication |
| `TOKEN` | Empty | Authentication token (optional) |
| `HUB_URL` | Empty | Hub URL (e.g., http://beszel-hub:8090) |
| `NVIDIA_VISIBLE_DEVICES` | Not set | GPU visibility (GPU agents only) |
| `NVIDIA_DRIVER_CAPABILITIES` | Not set | GPU capabilities (GPU agents only) |

## Troubleshooting

### Agent Pod Won't Start

```bash
# Check pod events and logs
kubectl describe pod <pod-name>
kubectl logs <pod-name>
```

### Cannot Connect to Hub

- Verify Hub is accessible from the pod's network
- Check DNS resolution: `kubectl exec <pod-name> -- nslookup beszel-hub.default.svc.cluster.local`
- Verify SSH key is correctly configured
- Check firewall rules for port 8090 (Hub) and 45876 (Agent)

### GPU Not Detected

- Confirm image is `henrygd/beszel-agent-nvidia`
- Verify NVIDIA runtime is installed on nodes
- Check GPU visibility: `kubectl exec <pod-name> -- nvidia-smi`
- Verify runtimeClassName matches your GPU runtime

### SSH Key Authentication Failed

- Verify key format (should be valid SSH public key)
- Check key is correctly set in `env.KEY`
- Ensure Hub has the corresponding private key
- Verify Hub can authenticate agents with this key

### High Memory Usage

Adjust resource limits:

```yaml
resources:
  limits:
    memory: 512Mi
  requests:
    memory: 256Mi
```

## Security Considerations

- Store SSH keys securely (use Kubernetes Secrets)
- Restrict container to read-only root filesystem if possible
- Limit resource usage with resource limits
- Use network policies to restrict traffic
- Run with minimal privileges
- Regularly update agent image to latest version
- Use private container registries if applicable

### Using Kubernetes Secrets for Configuration

The chart automatically creates a Kubernetes Secret to store sensitive authentication data:

```bash
# Install with all configuration options
helm install beszel-agent ./beszel-agent \
  --set env.KEY="ssh-ed25519 AAAA... your-public-key" \
  --set env.TOKEN="your-optional-token" \
  --set env.HUB_URL="http://beszel-hub:8090"
```

Or create the installation with a values file:

```yaml
# values.yaml
env:
  KEY: "ssh-ed25519 AAAA... your-public-key"
  TOKEN: "your-optional-token"
  HUB_URL: "http://beszel-hub:8090"
```

Configuration stored in Kubernetes Secrets (encrypted at rest):
- `KEY` - SSH public key for authentication (required)
- `TOKEN` - Authentication token (optional)

Configuration as regular environment variables:
- `HUB_URL` - Hub address (e.g., http://beszel-hub:8090 or https://beszel.example.com)

To verify the secret was created:

```bash
kubectl get secret beszel-agent
kubectl get secret beszel-agent -o jsonpath='{.data.ssh-key}' | base64 -d
```

## Support and Documentation

- **Project Homepage**: https://www.beszel.dev/
- **GitHub Repository**: https://github.com/henrygd/beszel
- **Agent Documentation**: https://www.beszel.dev/

**Note**: The main Beszel documentation describes Docker/Podman container monitoring. In Kubernetes, the agent focuses on node-level metrics. For Kubernetes-specific container/pod monitoring, use tools like metrics-server, Prometheus, or the Kubernetes Metrics API.

## Chart Information

- **Chart Version**: 0.1.0
- **App Version**: 0.18.7
- **Kubernetes Version**: 1.19+
- **Maintainer**: cloudwithdan (nikoloskid@pm.me)

## License

Please refer to the main Beszel project repository for license information.
