# Using Exoscale Compute as a Dedicated Backup Server

This guide configures an Exoscale Compute instance to automatically back up your servers to Exoscale Object Storage (SOS). The setup uses Plakar to create encrypted, deduplicated snapshots on a scheduled interval with web UI monitoring.

## Architecture

- **Backup Compute**: Runs Plakar and schedules backups
- **Source servers**: Exoscale servers to back up
- **Exoscale Object Storage (SOS)**: Stores encrypted backups

```
Exoscale Object Storage

Source Servers

SSH/SFTP

SSH/SFTP

SSH/SFTP

Store Snapshots

Web Server 1

Web Server 2

Server N

Backup Compute
Plakar + Scheduler

Kloset Store
Encrypted & Deduplicated
Backup
```

## Prerequisites

- Exoscale account with billing configured
- SSH keypair for instance access
- SSH access to source servers
- Basic familiarity with Plakar commands

## Create Object Storage Bucket

### Create bucket in Exoscale Portal

1. In the Exoscale portal, navigate to **Storage**
2. Click **Add** to create a new bucket
3. Configure:
   - Zone: Select region (note the name, it’ll be used to connect to the container e.g `ch-dk-2`)
   - Name: `plakar-backups` (must be globally unique)
4. Click **Add**

### Generate IAM API Keys

1. In the Exoscale portal, navigate to **IAM** → **Keys**
2. Click on **Add** to create new API keys, then provide a name and role, then click **Create**.
3. Copy the key and secret to a secure environment (you cannot see the secret once you leave the page)

## Create SSH Keypair

1. Generate SSH key locally and copy the public key:

```bash
$ ssh-keygen -t ed25519 -f ~/.ssh/id_exoscale -C "exoscale-backup"
$ cat ~/.ssh/id_exoscale.pub
```

2. In the Exoscale portal, navigate to **Compute** → **SSH Keys**
3. Click on **Add** then enter a name for the SSH Key and paste in the public key then click **Import**.

## Provision Backup Compute Instance

### Create compute instance

1. In the Exoscale Portal, navigate to **Compute** → **Instances**
2. Click **Add**
3. Configure:
   - Name: `plakar-backup`
   - Template: Ubuntu 24.04 LTS
   - Zone: Same as Object Storage bucket (recommended for better performance)
   - Instance Type: Small (2 vCPUs, 2 GB RAM) or any other you prefer
   - SSH Key: Select the SSH key we created before from the dropdown
4. Click **Add** to provision your compute

### Setup security group rules

1. Once the compute is provisioned, navigate to **Compute** → **Security Groups**
2. By default the compute will be assigned the `default` security group, click on the actions on default then click on **Details**
3. On the next page click on **Add Rule**
4. Configure:
   - Flow direction: Ingress
   - Protocol: TCP
   - Source Type: CIDR
   - Sources: `0.0.0.0/0` allows SSH from anywhere (for better security use your IP Address here)
   - Start & End port: 22
   - A description for the rule e.g. SSH Access
5. Click on **Create**

### Initial connection

Once instance is running, note the public IP and connect:

```bash
$ ssh ubuntu@<instance-ip>
```

## Install Plakar

Install Plakar on the instance using the [Plakar Installation Guide](/content/docs/main/quickstart/installation/index.html)

## Configure Object Storage

### Install S3 integration

```bash
$ plakar login -email you@example.com
$ plakar pkg add s3
```

### Add storage connector

```bash
$ plakar store add exoscale-sos-backups \
  location=s3://<SOS_ENDPOINT>/<BUCKET_NAME> \
  access_key=<YOUR_ACCESS_KEY> \
  secret_access_key=<YOUR_SECRET_KEY> \
  use_tls=true \
  passphrase='<YOUR_SECURE_PASSPHRASE>'
```

Replace:

- `<SOS_ENDPOINT>`: using the format `sos-{zone}.exo.io` where zone is one we selected for the bucket e.g `sos-ch-dk-2.exo.io`
- `<BUCKET_NAME>`: e.g., `plakar-backups`
- `<YOUR_ACCESS_KEY>` and `<YOUR_SECRET_KEY>`: From bucket API credentials
- `<YOUR_SECURE_PASSPHRASE>`: Strong passphrase for encryption

Passphrase

Configuring the passphrase in the store enables automated backups without prompts.

### Initialize Kloset Store

```bash
$ plakar at "@exoscale-sos-backups" create
```

## Configure SSH Access to Source Servers

### Install SFTP integration

```bash
$ plakar pkg add sftp
```

### Generate SSH keys for backups

```bash
$ ssh-keygen -t ed25519 -f ~/.ssh/id_ed25519_plakar -C "plakar@backup"
```

Press Enter for no passphrase.

### Copy keys to source servers

```bash
$ ssh-copy-id -i ~/.ssh/id_ed25519_plakar.pub user@source-server-1
$ ssh-copy-id -i ~/.ssh/id_ed25519_plakar.pub user@source-server-2
```

Test access:

```bash
$ ssh -i ~/.ssh/id_ed25519_plakar user@source-server-1 'echo "Success"'
```

### Create SSH aliases

```bash
$ cat >> ~/.ssh/config << 'EOF'
Host source-1
  HostName source-server-1.example.com
  User backupuser
  Port 22
  IdentityFile ~/.ssh/id_ed25519_plakar

Host source-2
  HostName source-server-2.example.com
  User backupuser
  Port 22
  IdentityFile ~/.ssh/id_ed25519_plakar
EOF
```

Test:

```bash
$ ssh source-1 'echo "Alias works"'
```

## Configure Backup Sources

Add source connectors for each server:

```bash
$ plakar source add web-server-1 sftp://source-1:/var/www
$ plakar source add web-server-2 sftp://source-2:/var/www
```

Verify:

```bash
$ plakar source show
```

## Test Backup

Run a manual backup to verify configuration:

```bash
# Single source
$ plakar at "@exoscale-sos-backups" backup "@web-server-1"

# Multiple sources
$ plakar at "@exoscale-sos-backups" backup "@web-server-1" "@web-server-2"
```

List snapshots:

```bash
$ plakar at "@exoscale-sos-backups" ls
```

## Schedule Automatic Backups

For scheduler configuration and systemd service setup, follow the same steps as the [OVHcloud backup server guide](/content/docs/main/guides/ovhcloud/ovhcloud-as-a-dedicated-backup-server/#schedule-automatic-backups/index.html), replacing:

- `@ovhcloud-s3-backups` with `@exoscale-sos-backups`
- `ubuntu` with your actual username if different

The scheduler configuration, systemd services, and web UI setup are identical on any Linux machine.

## Troubleshooting

**Authentication errors**

- Verify SSH keys and user permissions on source servers

**Can’t connect to Object Storage**

- Check S3 credentials and endpoint URL
- Verify passphrase: `plakar store show exoscale-sos-backups`
- Confirm bucket name and zone endpoint match

**Permission denied**

- Ensure SSH user has read access to backup directories

**Services won’t start**

- Check status: `systemctl status plakar-scheduler`
- View logs: `journalctl -u plakar-scheduler` or `journalctl -u plakar-ui`

**Alternative UI access**

- Install Plakar locally and configure the same store with Exoscale SOS credentials to access backups without compute instance connection.