albatross/app/vmmd.ml

269 lines
10 KiB
OCaml

(* (c) 2017 Hannes Mehnert, all rights reserved *)
open Vmm_cli
open Vmm_core
type stats = {
start : Ptime.t ;
vm_created : int ;
vm_destroyed : int ;
}
let s = ref { start = Ptime_clock.now () ; vm_created = 0 ; vm_destroyed = 0 }
let pp_stats ppf s =
let diff = Ptime.(diff (Ptime_clock.now ()) s.start) in
Fmt.pf ppf "up %a: %d vms created, %d vms destroyed, %d running"
Ptime.Span.pp diff
s.vm_created s.vm_destroyed (s.vm_created - s.vm_destroyed)
open Lwt.Infix
let version = `AV3
let state = ref (Vmm_vmmd.init version)
let create process cont =
match cont !state with
| Error (`Msg msg) ->
Logs.err (fun m -> m "create continuation failed %s" msg) ;
Lwt.return_unit
| Ok (state', out, name, vm) ->
state := state' ;
s := { !s with vm_created = succ !s.vm_created } ;
Lwt.async (fun () ->
Vmm_lwt.wait_and_clear vm.Unikernel.pid >>= fun r ->
let state', out' = Vmm_vmmd.handle_shutdown !state name vm r in
state := state' ;
s := { !s with vm_destroyed = succ !s.vm_destroyed } ;
process "handle shutdown (stat, log)" out' >|= fun () ->
let state', waiter_opt = Vmm_vmmd.waiter !state name in
state := state' ;
(match waiter_opt with
| None -> ()
| Some wakeme -> Lwt.wakeup wakeme ())) ;
process "setting up stat, log, reply" out
let register who header =
match Vmm_vmmd.register !state who Lwt.task with
| None -> Error (`Data (header, `Failure "task already registered"))
| Some (state', task) -> state := state' ; Ok task
let handle process fd addr =
Logs.debug (fun m -> m "connection from %a" Vmm_lwt.pp_sockaddr addr) ;
(* now we need to read a packet and handle it
(1)
(a) easy for info (look up name/prefix in resources)
(b) destroy looks up vm in resources, executes kill (wait for pid will do the cleanup)
logs "destroy issued"
(c) create initiates the vm startup procedure:
write image file, create fifo, create tap(s), send fifo to console
-- Lwt effects happen (console) --
executes solo5-hvt + waiter, send stats pid and taps, inserts await into state, logs "created vm"
-- Lwt effects happen (stats, logs, wait_and_clear) --
(2) goto (1)
*)
let rec loop () =
Logs.debug (fun m -> m "now reading") ;
Vmm_lwt.read_wire fd >>= function
| Error _ ->
Logs.err (fun m -> m "error while reading") ;
Lwt.return_unit
| Ok wire ->
Logs.debug (fun m -> m "read %a" Vmm_commands.pp_wire wire) ;
let state', data, next = Vmm_vmmd.handle_command !state wire in
state := state' ;
process "handle command" data >>= fun () ->
match next with
| `Loop -> loop ()
| `End -> Lwt.return_unit
| `Create cont -> create process cont
| `Wait (who, out) ->
(match register who (fst wire) with
| Error out' -> process "wait" [ out' ]
| Ok task ->
task >>= fun () ->
process "wait" [ out ])
| `Wait_and_create (who, next) ->
(match register who (fst wire) with
| Error out' -> process "wait and create" [ out' ]
| Ok task ->
task >>= fun () ->
let state', data, n = next !state in
state := state' ;
process "wait and create" data >>= fun () ->
match n with
| `End -> Lwt.return_unit
| `Create cont -> create process cont)
in
loop () >>= fun () ->
Vmm_lwt.safe_close fd
let init_sock sock =
let name = socket_path sock in
let c = Lwt_unix.(socket PF_UNIX SOCK_STREAM 0) in
Lwt_unix.set_close_on_exec c ;
Lwt.catch (fun () ->
Lwt_unix.(connect c (ADDR_UNIX name)) >|= fun () -> Some c)
(fun e ->
Logs.warn (fun m -> m "error %s connecting to socket %s"
(Printexc.to_string e) name) ;
(Lwt.catch (fun () -> Lwt_unix.close c) (fun _ -> Lwt.return_unit)) >|= fun () ->
None)
let create_mbox sock =
init_sock sock >|= function
| None -> None
| Some fd ->
let mvar = Lwt_mvar.create_empty () in
(* could be more elaborate:
if <log> fails, we can reconnect and spit our more log messages to the new socket
if <console> fails, all running VMs terminate, so we can terminate as well ;)
if <stat> fails, we'd need to retransmit all VM info to stat (or stat has to ask at connect) *)
let rec loop () =
Lwt_mvar.take mvar >>= fun data ->
Logs.debug (fun m -> m "writing %a" Vmm_commands.pp_wire data) ;
Vmm_lwt.write_wire fd data >>= function
| Ok () -> loop ()
| Error `Exception -> invalid_arg ("exception while writing to " ^ Fmt.to_to_string pp_socket sock) ;
in
Lwt.async loop ;
Some (mvar, fd, Lwt_mutex.create ())
let server_socket sock =
let name = socket_path sock in
(Lwt_unix.file_exists name >>= function
| true -> Lwt_unix.unlink name
| false -> Lwt.return_unit) >>= fun () ->
let s = Lwt_unix.(socket PF_UNIX SOCK_STREAM 0) in
Lwt_unix.set_close_on_exec s ;
Lwt_unix.(bind s (ADDR_UNIX name)) >|= fun () ->
Lwt_unix.listen s 1 ;
s
let rec stats_loop () =
Logs.info (fun m -> m "%a" pp_stats !s) ;
Lwt_unix.sleep 600. >>= fun () ->
stats_loop ()
let jump _ =
Sys.(set_signal sigpipe Signal_ignore);
match Vmm_vmmd.restore_unikernels () with
| Error (`Msg msg) -> Logs.err (fun m -> m "bailing out: %s" msg)
| Ok old_unikernels ->
Lwt_main.run
(server_socket `Vmmd >>= fun ss ->
(create_mbox `Log >|= function
| None -> invalid_arg "cannot connect to log socket"
| Some l -> l) >>= fun (l, l_fd, l_mut) ->
let self_destruct_mutex = Lwt_mutex.create () in
let self_destruct () =
Lwt_mutex.with_lock self_destruct_mutex (fun () ->
(if Vmm_vmmd.killall !state then
(* not too happy about the sleep here, but cleaning up resources
is really important (fifos, vm images, tap devices) - which
is done asynchronously (in the task waitpid() on the pid) *)
Lwt_unix.sleep 1.
else
Lwt.return_unit) >>= fun () ->
Vmm_lwt.safe_close ss)
in
Sys.(set_signal sigterm (Signal_handle (fun _ -> Lwt.async self_destruct)));
(create_mbox `Console >|= function
| None -> invalid_arg "cannot connect to console socket"
| Some c -> c) >>= fun (c, c_fd, c_mut) ->
create_mbox `Stats >>= fun s ->
let write_reply txt (header, cmd) name mvar fd mut =
Lwt_mutex.with_lock mut (fun () ->
Lwt_mvar.put mvar (header, cmd) >>= fun () ->
Vmm_lwt.read_wire fd) >|= function
| Ok (header', reply) ->
if not Vmm_commands.(version_eq header.version header'.version) then begin
Logs.err (fun m -> m "%s: wrong version (got %a, expected %a) in reply from %s"
txt
Vmm_commands.pp_version header'.Vmm_commands.version
Vmm_commands.pp_version header.Vmm_commands.version
name) ;
invalid_arg "bad version received"
end else if not Vmm_commands.(Int64.equal header.sequence header'.sequence) then begin
Logs.err (fun m -> m "%s: wrong id %Lu (expected %Lu) in reply from %s"
txt header'.Vmm_commands.sequence header.Vmm_commands.sequence name) ;
invalid_arg "wrong sequence number received"
end else begin
Logs.debug (fun m -> m "%s: received valid reply from %s %a"
txt name Vmm_commands.pp_wire (header', reply)) ;
match reply with
| `Success _ -> ()
| `Failure msg ->
(* can we programatically solve such a situation? *)
(* we at least know e.g when writing to console resulted in an error,
that we can't continue but need to roll back -- and not continue
with execvp() *)
Logs.err (fun m -> m "%s: received failure %s from %s" txt msg name)
| _ ->
Logs.err (fun m -> m "%s: unexpected data from %s" txt name) ;
invalid_arg "unexpected data"
end
| Error _ ->
Logs.err (fun m -> m "error in read from %s" name) ;
invalid_arg "communication failure"
in
let out txt = function
| `Stat wire ->
begin match s with
| None -> Lwt.return_unit
| Some (s, s_fd, s_mut) -> write_reply txt wire "stats" s s_fd s_mut
end
| `Log wire -> write_reply txt wire "log" l l_fd l_mut
| `Cons wire -> write_reply txt wire "console" c c_fd c_mut
in
let process ?fd txt wires =
Lwt_list.iter_p (function
| (#Vmm_vmmd.service_out as o) -> out txt o
| `Data wire -> match fd with
| None ->
Logs.app (fun m -> m "%s received %a" txt Vmm_commands.pp_wire wire) ;
Lwt.return_unit
| Some fd ->
(* TODO should we terminate the connection on write failure? *)
Vmm_lwt.write_wire fd wire >|= fun _ ->
()) wires
in
Lwt.async stats_loop ;
let start_unikernel (name, config) =
match Vmm_vmmd.handle_create !state [] name config with
| Error (`Msg msg) ->
Logs.err (fun m -> m "failed to restart %a: %s" Name.pp name msg) ;
Lwt.return_unit
| Ok (state', out, `Create next) ->
state := state' ;
process "create from dump" out >>= fun () ->
create process next
in
Lwt_list.iter_p start_unikernel (Vmm_trie.all old_unikernels) >>= fun () ->
Lwt.catch (fun () ->
let rec loop () =
Lwt_unix.accept ss >>= fun (fd, addr) ->
Lwt_unix.set_close_on_exec fd ;
Lwt.async (fun () -> handle (process ~fd) fd addr) ;
loop ()
in
loop ())
(fun e ->
Logs.err (fun m -> m "exception %s, shutting down" (Printexc.to_string e));
self_destruct ()))
open Cmdliner
let cmd =
Term.(const jump $ setup_log),
Term.info "vmmd" ~version:"%%VERSION_NUM%%"
let () = match Term.eval cmd with `Ok () -> exit 0 | _ -> exit 1