Most allocation hooks don't need to know when a single task within the
allocation is restarted. The check watcher for group services triggers the
alloc runner to restart all tasks, but the alloc runner's `Restart` method
doesn't trigger any of the alloc hooks, including the group service hook. The
result is that after the first time a check triggers a restart, we'll never
restart the tasks of an allocation again.
This commit adds a `RunnerTaskRestartHook` interface so that alloc runner
hooks can act if a task within the alloc is restarted. The only implementation
is in the group service hook, which will force a re-registration of the
alloc's services and fix check restarts.
copy struct values
ensure groupserviceHook implements RunnerPreKillhook
run deregister first
test that shutdown times are delayed
move magic number into variable
Some of the context uses in TR hooks are useless (Killed during Stop
never seems meaningful).
None of the hooks are interruptable for graceful shutdown which is
unfortunate and probably needs fixing.
Builds upon earlier commit that cleans up restored handles of terminal
allocs by also emitting terminated events and calling exited hooks when
appropriate.
This commit is a significant change. TR.Run is now always executed, even
for terminal allocations. This was changed to allow TR.Run to cleanup
(run stop hooks) if a handle was recovered.
This is intended to handle the case of Nomad receiving a
DesiredStatus=Stop allocation update, persisting it, but crashing before
stopping AR/TR.
The commit also renames task runner hook data as it was very easy to
accidently set state on Requests instead of Responses using the old
field names.
plugins/driver: update driver interface to support streaming stats
client/tr: use streaming stats api
TODO:
* how to handle errors and closed channel during stats streaming
* prevent tight loop if Stats(ctx) returns an error
drivers: update drivers TaskStats RPC to handle streaming results
executor: better error handling in stats rpc
docker: better control and error handling of stats rpc
driver: allow stats to return a recoverable error
As part of deprecating legacy drivers, we're moving the env package to a
new drivers/shared tree, as it is used by the modern docker and rkt
driver packages, and is useful for 3rd party plugins.
This PR introduces a device hook that retrieves the device mount
information for an allocation. It also updates the computed node class
computation to take into account devices.
TODO Fix the task runner unit test. The environment variable is being
lost even though it is being properly set in the prestart hook.
Tim Gross