spore.host

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Frequently Asked Questions ​

General ​

What is spore.host? ​

spore.host is a set of free, open-source tools for launching ephemeral EC2 instances that manage their own lifecycle. Every instance you launch gets a time-to-live and an idle detector — the TTL terminates it when the deadline passes, and idle detection stops it between tasks — so you never pay for idle compute by accident.

What's the difference between truffle and spawn? ​

Truffle is read-only — it finds and compares instance types, Spot prices, and quotas. Think of it as search and research before you commit.

Spawn is the launcher — it provisions instances, installs spored, and manages the full lifecycle.

What is spored? ​

Spored is a small daemon that runs on each spawned instance. It enforces the TTL, detects idle conditions, handles Spot interruptions, registers a DNS name, and sends lifecycle notifications to Slack or Teams. It runs independently of your laptop — you can close your terminal and spored keeps working.

Is spore.host free? ​

Yes. The CLI tools (truffle, spawn, lagotto, spore-host-mcp) are free and open source (Apache 2.0). You pay only for the AWS resources you use — EC2 instance hours, storage, and data transfer. spore.host helps minimise these costs through TTL enforcement and idle detection.

AWS and costs ​

How does spore.host prevent surprise bills? ​

Every instance launched through spawn has a TTL — a hard deadline at which it terminates. Idle detection adds an earlier soft cutoff: if the instance has been unused for a configured period, it stops or hibernates before the TTL fires. You set both at launch time, or save them as defaults.

Can I use spore.host with multiple AWS accounts? ​

Yes. Use AWS_PROFILE=my-profile spawn launch ... or spawn launch --profile my-profile ... to specify which credential profile to use per launch.

What AWS permissions does spore.host need? ​

The baseline policy is documented at IAM Permissions. In brief the core permissions are: EC2 describe, run, stop, terminate, tag, and create tags; and IAM pass-role for the spored instance profile. Optional features add their own permissions only when you use them — e.g. Route 53 is needed only with --dns (subdomain assignment), not for a normal launch.

Instances ​

What instance types are supported? ​

All EC2 instance types. Common choices for research:

  • General purpose: m7i.large, m7i.xlarge
  • CPU-intensive: c7i.2xlarge, c6i.4xlarge
  • Memory-intensive: r7i.2xlarge, r6i.8xlarge
  • GPU (training): p4d.24xlarge, g5.2xlarge
  • GPU (inference): g5.xlarge, g4dn.xlarge
  • Smallest / cheapest: t3.micro, t2.micro (often Free Tier eligible, but eligibility varies by account — check the price Truffle shows)

Can I use a custom AMI? ​

Yes: spawn launch --ami ami-XXXXXXXXX. Spored is installed via user-data at launch, so it works with any Amazon Linux 2, Amazon Linux 2023, or Ubuntu AMI.

Can I extend the TTL after launch? ​

Yes, at any time: spawn extend my-instance 4h — or from Slack: /spore extend my-instance 4h.

What's the maximum TTL? ​

720 hours (30 days). Setting --ttl 0 disables auto-termination, which is not recommended for anything other than long-lived development environments.

What happens to a Spot instance when AWS interrupts it? ​

Spored receives the two-minute warning via the EC2 metadata service. It runs your --pre-stop hook if configured (for saving checkpoints), sends a Slack notification, and terminates gracefully.

SSH and connectivity ​

How do I connect? ​

sh
spawn connect my-instance   # finds your key and connects; falls back to SSM

spawn connect logs you in as your own username — the instance creates a Linux user matching your local login name and installs your SSH public key into its authorized_keys, so you connect as you (not a generic ec2-user). It finds your key automatically; if SSH isn't reachable it falls back to AWS Session Manager. Aliased as spawn ssh.

Which SSH key does spawn use? ​

If you have a default key — ~/.ssh/id_ed25519 (or ~/.ssh/id_rsa) — spawn imports that public key, so you connect with the key you already use. Only if you have no default key does it generate and use a managed key under ~/.spawn/keys/. Point spawn connect at a specific key with --key <path>.

Why does SSH fail right after launch? ​

The instance takes 30–90 seconds to boot and start sshd. Wait and retry, or use spawn connect which handles the retry (and falls back to SSM).

spawn connect can't reach the instance — what now? ​

  • No public IP / private subnet: use SSM instead — spawn connect my-instance --session-manager (no inbound SSH needed).
  • Security group: if you're connecting over SSH, port 22 must allow your IP. spawn opens it for you at launch; a later network change can break it.
  • Wrong user or key: override with --user <name> / --key <path>. By default the user is your local username and the key is your default/managed key.
  • Instance stopped: spawn connect auto-starts a stopped/hibernated instance unless you pass --no-start.

Can I use my own EC2 key pair? ​

Yes — spawn launch --key-name my-existing-keypair uses an existing EC2 key pair by name. Most users don't need this: spawn imports your local ~/.ssh public key automatically (see above).

Idle detection ​

Why didn't my instance terminate when I expected it to? ​

Idle detection considers CPU, network I/O, disk I/O, GPU utilisation, active SSH sessions, and (if configured) specific process names. If any signal indicates activity, the idle timer resets. Check spawn status my-instance to see current activity levels.

I'm running RStudio — why does idle detection keep resetting? ​

The RStudio browser tab maintains a TCP connection to the server even when you're not actively using it. Use --active-processes rsession to base idle detection on whether an R session process is actually running, rather than TCP connections.

Can I disable idle detection? ​

Yes: spawn launch --idle-timeout 0. The TTL still applies as the hard outer bound.

Slack / Teams ​

Do I need to set up Slack to use spore.host? ​

No. Slack and Teams integration is optional. spore.host works fully without it — you just won't get DM notifications or slash command control.

Can multiple people control the same instance from Slack? ​

Yes. Register each user separately with spawn notify register, granting them the actions they need. Each person can then use /spore status, /spore stop, etc. on that instance.

Something stopped working after I updated the Slack app scopes. ​

Updating app scopes regenerates the signing secret. Re-register with the new secret: spawn notify workspace-add --platform slack --workspace-id T0... --signing-secret <new-secret>