There's a bug in go1.11 that causes some io operations on windows to
return incorrect errors for some cases when Stat-ing files. To avoid
upgrading to go1.12 in a point release, here we loosen up the cases
where we will attempt to create fifos, and add some logging of
underlying stat errors to help with debugging.
Previously, if a channel is closed, we retry the Stats call. But, if that call
fails, we go in a backoff loop without calling Stats ever again.
Here, we use a utility function for calling driverHandle.Stats call that retries
as one expects.
I aimed to preserve the logging formats but made small improvements as I saw fit.
When an alloc runner prestart hook fails, the task runners aren't invoked
and they remain in a pending state.
This leads to terrible results, some of which are:
* Lockup in GC process as reported in https://github.com/hashicorp/nomad/pull/5861
* Lockup in shutdown process as TR.Shutdown() waits for WaitCh to be closed
* Alloc not being restarted/rescheduled to another node (as it's still in
pending state)
* Unexpected restart of alloc on a client restart, potentially days/weeks after
alloc expected start time!
Here, we treat all tasks to have failed if alloc runner prestart hook fails.
This fixes the lockups, and permits the alloc to be rescheduled on another node.
While it's desirable to retry alloc runner in such failures, I opted to treat it
out of scope. I'm afraid of some subtles about alloc and task runners and their
idempotency that's better handled in a follow up PR.
This might be one of the root causes for
https://github.com/hashicorp/nomad/issues/5840 .
When fetching node alloc assignments, be defensive against a stale read before
killing local nodes allocs.
The bug is when both client and servers are restarting and the client requests
the node allocation for the node, it might get stale data as server hasn't
finished applying all the restored raft transaction to store.
Consequently, client would kill and destroy the alloc locally, just to fetch it
again moments later when server store is up to date.
The bug can be reproduced quite reliably with single node setup (configured with
persistence). I suspect it's too edge-casey to occur in production cluster with
multiple servers, but we may need to examine leader failover scenarios more closely.
In this commit, we only remove and destroy allocs if the removal index is more
recent than the alloc index. This seems like a cheap resiliency fix we already
use for detecting alloc updates.
A more proper fix would be to ensure that a nomad server only serves
RPC calls when state store is fully restored or up to date in leadership
transition cases.
Although this operation is safe on linux, it is not safe on Windows when
using the named pipe interface. To provide a ~reasonable common api
abstraction, here we switch to returning File exists errors on the unix
api.
On unix platforms, it is safe to re-open fifo's for reading after the
first creation if the file is already a fifo, however this is not
possible on windows where this triggers a permissions error on the
socket path, as you cannot recreate it.
We can't transparently handle this in the CreateAndRead handle, because
the Access Is Denied error is too generic to reliably be an IO error.
Instead, we add an explict API for opening a reader to an existing FIFO,
and check to see if the fifo already exists inside the calling package
(e.g logmon)
This change fixes a bug where nomad would avoid running alloc tasks if
the alloc is client terminal but the server copy on the client isn't
marked as running.
Here, we fix the case by having task runner uses the
allocRunner.shouldRun() instead of only checking the server updated
alloc.
Here, we preserve much of the invariants such that `tr.Run()` is always
run, and don't change the overall alloc runner and task runner
lifecycles.
Fixes https://github.com/hashicorp/nomad/issues/5883
Currently, if killTask results in the termination of a process before
calling WaitTask, Restart() will incorrectly return a TaskNotFound
error when using the raw_exec driver on Windows.
Currently, nomad "plugin" processes (e.g. executor, logmon, docker_logger) are started as CLI
commands to be handled by command CLI framework. Plugin launchers use
`discover.NomadBinary()` to identify the binary and start it.
This has few downsides: The trivial one is that when running tests, one
must re-compile the nomad binary as the tests need to invoke the nomad
executable to start plugin. This is frequently overlooked, resulting in
puzzlement.
The more significant issue with `executor` in particular is in relation
to external driver:
* Plugin must identify the path of invoking nomad binary, which is not
trivial; `discvoer.NomadBinary()` now returns the path to the plugin
rather than to nomad, preventing external drivers from launching
executors.
* The external driver may get a different version of executor than it
expects (specially if we make a binary incompatible change in future).
This commit addresses both downside by having the plugin invocation
handling through an `init()` call, similar to how libcontainer init
handler is done in [1] and recommened by libcontainer [2]. `init()`
will be invoked and handled properly in tests and external drivers.
For external drivers, this change will cause external drivers to launch
the executor that's compiled against.
There a are a couple of downsides to this approach:
* These specific packages (i.e executor, logmon, and dockerlog) need to
be careful in use of `init()`, package initializers. Must avoid having
command execution rely on any other init in the package. I prefixed
files with `z_` (golang processes files in lexical order), but ensured
we don't depend on order.
* The command handling is spread in multiple packages making it a bit
less obvious how plugin starts are handled.
[1] drivers/shared/executor/libcontainer_nsenter_linux.go
[2] eb4aeed24f/libcontainer (using-libcontainer)
- updated region in job metadata that gets persisted to nomad datastore
- fixed many unrelated unit tests that used an invalid region value
(they previously passed because hcl wasn't getting picked up and
the job would default to global region)
We currently only run cleanup Service Hooks when a task is either
Killed, or Exited. However, due to the implementation of a task runner,
tasks are only Exited if they every correctly started running, which is
not true when you recieve an error early in the task start flow, such as
not being able to pull secrets from Vault.
This updates the service hook to also call consul deregistration
routines during a task Stop lifecycle event, to ensure that any
registered checks and services are cleared in such cases.
fixes#5770
When a client is running against an old server (e.g. running 0.8),
`alloc.AllocatedResources` may be nil, and we need to check the
deprecated `alloc.TaskResources` instead.
Fixes https://github.com/hashicorp/nomad/issues/5810
Alloc runner already tracks tasks associated with alloc. Here, we
become defensive by relying on the alloc runner tracked tasks, rather
than depend on server never updating the job unexpectedly.
This exposes a client flag to disable nomad remote exec support in
environments where access to tasks ought to be restricted.
I used `disable_remote_exec` client flag that defaults to allowing
remote exec. Opted for a client config that can be used to disable
remote exec globally, or to a subset of the cluster if necessary.
This fixes an issue where batch and service workloads would never be
restarted due to indefinitely blocking on a nil channel.
It also raises the restoration logging message to `Info` to simplify log
analysis.
Without this change, alloc_endpoint cancel the context passed to handler
when we detect EOF. This races driver in setting exit code; and we run
into a case where the exec process terminates cleanly yet we attempt to
mark it as failed with context error.
Here, we rely on the driver to handle errors returned from Stream and
without racing to set an error.
Registration and restoring allocs don't share state or depend on each
other in any way (syncing allocs with servers is done outside of
registration).
Since restoring is synchronous, start the registration goroutine first.
For nodes with lots of allocs to restore or close to their heartbeat
deadline, this could be the difference between becoming "lost" or not.
Refactoring of 104067bc2b2002a4e45ae7b667a476b89addc162
Switch the MarkLive method for a chan that is closed by the client.
Thanks to @notnoop for the idea!
The old approach called a method on most existing ARs and TRs on every
runAllocs call. The new approach does a once.Do call in runAllocs to
accomplish the same thing with less work. Able to remove the gate
abstraction that did much more than was needed.
Fixes#1795
Running restored allocations and pulling what allocations to run from
the server happen concurrently. This means that if a client is rebooted,
and has its allocations rescheduled, it may restart the dead allocations
before it contacts the server and determines they should be dead.
This commit makes tasks that fail to reattach on restore wait until the
server is contacted before restarting.
Related to #4280
This PR adds
`client.allocs.<job>.<group>.<alloc>.<task>.memory.allocated` as a gauge
in bytes to metrics to ease calculating how close a task is to OOMing.
```
'nomad.client.allocs.memory.allocated.example.cache.6d98cbaf-d6bc-2a84-c63f-bfff8905a9d8.redis.rusty': 268435456.000
'nomad.client.allocs.memory.cache.example.cache.6d98cbaf-d6bc-2a84-c63f-bfff8905a9d8.redis.rusty': 5677056.000
'nomad.client.allocs.memory.kernel_max_usage.example.cache.6d98cbaf-d6bc-2a84-c63f-bfff8905a9d8.redis.rusty': 0.000
'nomad.client.allocs.memory.kernel_usage.example.cache.6d98cbaf-d6bc-2a84-c63f-bfff8905a9d8.redis.rusty': 0.000
'nomad.client.allocs.memory.max_usage.example.cache.6d98cbaf-d6bc-2a84-c63f-bfff8905a9d8.redis.rusty': 8908800.000
'nomad.client.allocs.memory.rss.example.cache.6d98cbaf-d6bc-2a84-c63f-bfff8905a9d8.redis.rusty': 876544.000
'nomad.client.allocs.memory.swap.example.cache.6d98cbaf-d6bc-2a84-c63f-bfff8905a9d8.redis.rusty': 0.000
'nomad.client.allocs.memory.usage.example.cache.6d98cbaf-d6bc-2a84-c63f-bfff8905a9d8.redis.rusty': 8208384.000
```
* client: was not using up-to-date client state in determining which alloc count towards allocated resources
* Update client/client.go
Co-Authored-By: cgbaker <cgbaker@hashicorp.com>
This removes an unnecessary shared lock between discovery and heartbeating
which was causing heartbeats to be missed upon retries when a single server
fails. Also made a drive by fix to call the periodic server shuffler goroutine.
This fixes a confusing UX where a previously successful deployment's
healthy/unhealthy count would get updated if any allocations failed after
the deployment was already marked as successful.
Fixes https://github.com/hashicorp/nomad/issues/5587
When a nomad 0.9 client is handling an alloc generated by a nomad 0.8
server, we should check the alloc.TaskResources for networking details
rather than task.Resources.
We check alloc.TaskResources for networking for other tasks in the task
group [1], so it's a bit odd that we used the task.Resources struct
here. TaskRunner also uses `alloc.TaskResources`[2].
The task.Resources struct in 0.8 was sparsly populated, resulting to
storing of 0 in port mapping env vars:
```
vagrant@nomad-server-01:~$ nomad version
Nomad v0.8.7 (21a2d93eecf018ad2209a5eab6aae6c359267933+CHANGES)
vagrant@nomad-server-01:~$ nomad server members
Name Address Port Status Leader Protocol Build Datacenter Region
nomad-server-01.global 10.199.0.11 4648 alive true 2 0.8.7 dc1 global
vagrant@nomad-server-01:~$ nomad alloc status -json 5b34649b | jq '.Job.TaskGroups[0].Tasks[0].Resources.Networks'
[
{
"CIDR": "",
"Device": "",
"DynamicPorts": [
{
"Label": "db",
"Value": 0
}
],
"IP": "",
"MBits": 10,
"ReservedPorts": null
}
]
vagrant@nomad-server-01:~$ nomad alloc status -json 5b34649b | jq '.TaskResources'
{
"redis": {
"CPU": 500,
"DiskMB": 0,
"IOPS": 0,
"MemoryMB": 256,
"Networks": [
{
"CIDR": "",
"Device": "eth1",
"DynamicPorts": [
{
"Label": "db",
"Value": 21722
}
],
"IP": "10.199.0.21",
"MBits": 10,
"ReservedPorts": null
}
]
}
}
```
Also, updated the test values to mimic how Nomad 0.8 structs are
represented, and made its result match the non compact values in
`TestEnvironment_AsList`.
[1] 24e9040b18/client/taskenv/env.go (L624-L639)
[2] https://github.com/hashicorp/nomad/blob/master/client/allocrunner/taskrunner/task_runner.go#L287-L303
This helper returns the token as well as the ACL policy, to be used in a later
commit for logging the token info associated with nomad exec invocation.
This command will be used to send a signal to either a single task within an
allocation, or all of the tasks if <task-name> is omitted. If the sent signal
terminates the allocation, it will be treated as if the allocation has crashed,
rather than as if it was operator-terminated.
Signal validation is currently handled by the driver itself and nomad
does not attempt to restrict or validate them.
Noticed that `detected drivers` log line was misleading - when a driver
doesn't fingerprint before timeout, their health status is empty string
`""` which we would mark as detected.
Now, we log all drivers along with their state to ease driver
fingerprint debugging.
I noticed that `watchNodeUpdates()` almost immediately after
`registerAndHeartbeat()` calls `retryRegisterNode()`, well after 5
seconds.
This call is unnecessary and made debugging a bit harder. So here, we
ensure that we only re-register node for new node events, not for
initial registration.
Here we retain 0.8.7 behavior of waiting for driver fingerprints before
registering a node, with some timeout. This is needed for system jobs,
as system job scheduling for node occur at node registration, and the
race might mean that a system job may not get placed on the node because
of missing drivers.
The timeout isn't strictly necessary, but raising it to 1 minute as it's
closer to indefinitely blocked than 1 second. We need to keep the value
high enough to capture as much drivers/devices, but low enough that
doesn't risk blocking too long due to misbehaving plugin.
Fixes https://github.com/hashicorp/nomad/issues/5579
Currently, when logmon fails to reattach, we will retry reattachment to
the same pid until the task restart specification is exhausted.
Because we cannot clear hook state during error conditions, it is not
possible for us to signal to a future restart that it _shouldn't_
attempt to reattach to the plugin.
Here we revert to explicitly detecting reattachment seperately from a
launch of a new logmon, so we can recover from scenarios where a logmon
plugin has failed.
This is a net improvement over the current hard failure situation, as it
means in the most common case (the pid has gone away), we can recover.
Other reattachment failure modes where the plugin may still be running
could potentially cause a duplicate process, or a subsequent failure to launch
a new plugin.
If there was a duplicate process, it could potentially cause duplicate
logging. This is better than a production workload outage.
If there was a subsequent failure to launch a new plugin, it would fail
in the same (retry until restarts are exhausted) as the current failure
mode.
Renewal time was being calculated as 10s+Intn(lease-10s), so the renewal
time could be very rapid or within 1s of the deadline: [10s, lease)
This commit fixes the renewal time by calculating it as:
(lease/2) +/- 10s
For a lease of 60s this means the renewal will occur in [20s, 40s).
Revert "fingerprint Constraints and Affinities have Equals, as set"
This reverts commit 596f16fb5f1a4a6766a57b3311af806d22382609.
Revert "client tests assert the independent handling of interface and speed"
This reverts commit 7857ac5993a578474d0570819f99b7b6e027de40.
Revert "structs missed applying a style change from the review"
This reverts commit 658916e3274efa438beadc2535f47109d0c2f0f2.
Revert "client, structs comments"
This reverts commit be2838d6baa9d382a5013fa80ea016856f28ade2.
Revert "client fingerprint updateNetworks preserves the network configuration"
This reverts commit fc309cb430e62d8e66267a724f006ae9abe1c63c.
Revert "client_test cleanup comments from review"
This reverts commit bc0bf4efb9114e699bc662f50c8f12319b6b3445.
Revert "client Networks Equals is set equality"
This reverts commit f8d432345b54b1953a4a4c719b9269f845e3e573.
Revert "struct cleanup indentation in RequestedDevice Equals"
This reverts commit f4746411cab328215def6508955b160a53452da3.
Revert "struct Equals checks for identity before value checking"
This reverts commit 0767a4665ed30ab8d9586a59a74db75d51fd9226.
Revert "fix client-test, avoid hardwired platform dependecy on lo0"
This reverts commit e89dbb2ab182b6368507dbcd33c3342223eb0ae7.
Revert "refactor error in client fingerprint to include the offending data"
This reverts commit a7fed726c6e0264d42a58410d840adde780a30f5.
Revert "add client updateNodeResources to merge but preserve manual config"
This reverts commit 84bd433c7e1d030193e054ec23474380ff3b9032.
Revert "refactor struts.RequestedDevice to have its own Equals"
This reverts commit 689782524090e51183474516715aa2f34908b8e6.
Revert "refactor structs.Resource.Networks to have its own Equals"
This reverts commit 49e2e6c77bb3eaa4577772b36c62205061c92fa1.
Revert "refactor structs.Resource.Devices to have its own Equals"
This reverts commit 4ede9226bb971ae42cc203560ed0029897aec2c9.
Revert "add COMPAT(0.10): Remove in 0.10 notes to impl for structs.Resources"
This reverts commit 49fbaace5298d5ccf031eb7ebec93906e1d468b5.
Revert "add structs.Resources Equals"
This reverts commit 8528a2a2a6450e4462a1d02741571b5efcb45f0b.
Revert "test that fingerprint resources are updated, net not clobbered"
This reverts commit 8ee02ddd23bafc87b9fce52b60c6026335bb722d.
This adds a `nomad alloc restart` command and api that allows a job operator
with the alloc-lifecycle acl to perform an in-place restart of a Nomad
allocation, or a given subtask.
Remove runLaunched tracking as Run is *always* called for killable
TaskRunners. TaskRunners which fail before Run can be called (during
NewTaskRunner or Restore) are not killable as they're never added to the
client's alloc map.
This PR switches to using plain fifo files instead of golang structs
managed by containerd/fifo library.
The library main benefit is management of opening fifo files. In Linux,
a reader `open()` request would block until a writer opens the file (and
vice-versa). The library uses goroutines so that it's the first IO
operation that blocks.
This benefit isn't really useful for us: Given that logmon simply
streams output in a separate process, blocking of opening or first read
is effectively the same.
The library additionally makes further complications for managing state
and tracking read/write permission that seems overhead for our use,
compared to using a file directly.
Looking here, I made the following incidental changes:
* document that we do handle if fifo files are already created, as we
rely on that behavior for logmon restarts
* use type system to lock read vs write: currently, fifo library returns
`io.ReadWriteCloser` even if fifo is opened for writing only!
Michael Schurter