## Overview Instances are virtual machines (VMs) running on the RunAtlas high-performance cloud infrastructure. Powered by KVM and orchestrated via CloudStack, our instances offer scalable compute for everything from lightweight web servers to data-intensive applications. ### Key Features - **Flexible Sizing**: Choose from a variety of instance types to match your workload (e.g., General Purpose, Compute Optimized, Memory Optimized). - **Persistent Storage**: All instances come with a Root Volume that persists through reboots. - **Network Isolation**: Instances run within secure [[Guest Networks]] or [[VPC]]s, ensuring traffic isolation. - **SSH Key Authentication**: Secure access via SSH keys injected at launch. ## Managing Instances ### Launching an Instance To create a new VM: 1. Navigate to **Compute > Instances**. 2. Click **Add Instance**. 3. **Zone**: Select your desired availability zone. 4. **Template**: Choose an OS image (e.g., **Ubuntu 24.04**). 5. **Compute Offering**: Select the CPU/RAM configuration. 6. **Data Disk**: Keep default or add extra storage. 7. **Network**: Attach to a [[Guest Networks|Guest Network]] or VPC Tier. 8. **SSH Key Pair**: Select a pre-uploaded key (see [[SSH Key Pairs]]). ### Lifecycle Actions Once running, you can perform several actions from the console: - **Stop**: Shuts down the OS and halts billing for compute resources (storage remains billed). - **Reboot**: Restarts the OS (equivalent to `reboot` command). - **Destroy**: Permanently deletes the instance and its root volume. **This action is irreversible.** - **View Console**: Opens a VNC web console for emergency access if SSH fails. ### Connecting Use the allocated **Public IP Address** (if assigned via NAT) or internal IP (if accessing via VPN/Private Network). ```bash ssh root@<PUBLIC_IP> ``` *Note: Default user is usually `root`, `ubuntu`, or `rocky` depending on the template.* ## Advanced Configuration - **User Data**: Pass cloud-init scripts at launch to automate software installation (see [[User Data Library]]). - **Security Groups**: Control inbound/outbound traffic at the instance level (managed via Network/ACLs). - **Snapshots**: Create point-in-time backups of your volumes (see [[Instance Snapshots]]).