# `Hyper.Node.FireVMM.GuestAgent`
[🔗](https://github.com/harmont-dev/hyper/blob/main/lib/hyper/node/fire_vmm/guest_agent.ex#L1)

Resolves the path of the `hyper-guest-agent` static musl binary that the
`:guest_agent_build` Mix compiler builds into `priv/guest-agent/` at compile
time. The agent ships inside the app (and its release) -- there is no separate
install step.

The binary runs as guest PID 1 inside a Firecracker microVM and is baked into
the rootfs before the VM boots. `path/1` is the single source of truth for
where each arch's binary lives; `ensure_installed/0` verifies the binary for
*this host's* arch is present and executable -- the only one a node needs,
since KVM boots same-arch guests.

# `ensure_installed`

```elixir
@spec ensure_installed() :: :ok | {:error, term()}
```

Returns `:ok` when the guest-agent binary for the current host arch is present
and executable. Returns `{:error, {:not_installed, arch}}` if it is missing,
`{:error, {:not_executable, arch}}` if it exists without an execute bit, or
`{:error, {:unsupported_arch, raw}}` if the host arch is unrecognised.

The binary is produced by the `:guest_agent_build` Mix compiler; a missing one
means `mix compile` could not build it for this arch (see that compiler).

# `path`

```elixir
@spec path(Sys.Arch.t()) :: Path.t()
```

Absolute path to the guest-agent binary for `arch` (under the app's priv dir).

---

*Consult [api-reference.md](api-reference.md) for complete listing*