Tools like `nomad-nodesim` are unable to implement a minimal implementation of
an allocrunner so that we can test the client communication without having to
lug around the entire allocrunner/taskrunner code base. The allocrunner was
implemented with an interface specifically for this purpose, but there were
circular imports that made it challenging to use in practice.
Move the AllocRunner interface into an inner package and provide a factory
function type. Provide a minimal test that exercises the new function so that
consumers have some idea of what the minimum implementation required is.
The `ephemeral_disk` block's `migrate` field allows for best-effort migration of
the ephemeral disk data to new nodes. The documentation says the `migrate` field
is only respected if `sticky=true`, but in fact if client ACLs are not set the
data is migrated even if `sticky=false`.
The existing behavior when client ACLs are disabled has existed since the early
implementation, so "fixing" that case now would silently break backwards
compatibility. Additionally, having `migrate` not imply `sticky` seems
nonsensical: it suggests that if we place on a new node we migrate the data but
if we place on the same node, we throw the data away!
Update so that `migrate=true` implies `sticky=true` as follows:
* The failure mode when client ACLs are enabled comes from the server not passing
along a migration token. Update the server so that the server provides a
migration token whenever `migrate=true` and not just when `sticky=true` too.
* Update the scheduler so that `migrate` implies `sticky`.
* Update the client so that we check for `migrate || sticky` where appropriate.
* Refactor the E2E tests to move them off the old framework and make the intention
of the test more clear.
* Update ioutil deprecated library references to os and io respectively
* Deal with the errors produced.
Add error handling to filEntry info
Add error handling to info
* test: use `T.TempDir` to create temporary test directory
This commit replaces `ioutil.TempDir` with `t.TempDir` in tests. The
directory created by `t.TempDir` is automatically removed when the test
and all its subtests complete.
Prior to this commit, temporary directory created using `ioutil.TempDir`
needs to be removed manually by calling `os.RemoveAll`, which is omitted
in some tests. The error handling boilerplate e.g.
defer func() {
if err := os.RemoveAll(dir); err != nil {
t.Fatal(err)
}
}
is also tedious, but `t.TempDir` handles this for us nicely.
Reference: https://pkg.go.dev/testing#T.TempDir
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
* test: fix TestLogmon_Start_restart on Windows
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
* test: fix failing TestConsul_Integration
t.TempDir fails to perform the cleanup properly because the folder is
still in use
testing.go:967: TempDir RemoveAll cleanup: unlinkat /tmp/TestConsul_Integration2837567823/002/191a6f1a-5371-cf7c-da38-220fe85d10e5/web/secrets: device or resource busy
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
Fixes#10200
**The bug**
A user reported receiving the following error when an alloc was placed
that needed to preempt existing allocs:
```
[ERROR] client.alloc_watcher: error querying previous alloc:
alloc_id=28... previous_alloc=8e... error="rpc error: alloc lookup
failed: index error: UUID must be 36 characters"
```
The previous alloc (8e) was already complete on the client. This is
possible if an alloc stops *after* the scheduling decision was made to
preempt it, but *before* the node running both allocations was able to
pull and start the preemptor. While that is hopefully a narrow window of
time, you can expect it to occur in high throughput batch scheduling
heavy systems.
However the RPC error made no sense! `previous_alloc` in the logs was a
valid 36 character UUID!
**The fix**
The fix is:
```
- prevAllocID: c.Alloc.PreviousAllocation,
+ prevAllocID: watchedAllocID,
```
The alloc watcher new func used for preemption improperly referenced
Alloc.PreviousAllocation instead of the passed in watchedAllocID. When
multiple allocs are preempted, a watcher is created for each with
watchedAllocID set properly by the caller. In this case
Alloc.PreviousAllocation="" -- which is where the `UUID must be 36 characters`
error was coming from! Sadly we were properly referencing
watchedAllocID in the log, so it made the error make no sense!
**The repro**
I was able to reproduce this with a dev agent with [preemption enabled](https://gist.github.com/schmichael/53f79cbd898afdfab76865ad8c7fc6a0#file-preempt-hcl)
and [lowered limits](https://gist.github.com/schmichael/53f79cbd898afdfab76865ad8c7fc6a0#file-limits-hcl)
for ease of repro.
First I started a [low priority count 3 job](https://gist.github.com/schmichael/53f79cbd898afdfab76865ad8c7fc6a0#file-preempt-lo-nomad),
then a [high priority job](https://gist.github.com/schmichael/53f79cbd898afdfab76865ad8c7fc6a0#file-preempt-hi-nomad)
that evicts 2 low priority jobs. Everything worked as expected.
However if I force it to use the [remotePrevAlloc implementation](https://github.com/hashicorp/nomad/blob/v1.3.0-beta.1/client/allocwatcher/alloc_watcher.go#L147),
it reproduces the bug because the watcher references PreviousAllocation
instead of watchedAllocID.
Fixes#2522
Skip embedding client.alloc_dir when building chroot. If a user
configures a Nomad client agent so that the chroot_env will embed the
client.alloc_dir, Nomad will happily infinitely recurse while building
the chroot until something horrible happens. The best case scenario is
the filesystem's path length limit is hit. The worst case scenario is
disk space is exhausted.
A bad agent configuration will look something like this:
```hcl
data_dir = "/tmp/nomad-badagent"
client {
enabled = true
chroot_env {
# Note that the source matches the data_dir
"/tmp/nomad-badagent" = "/ohno"
# ...
}
}
```
Note that `/ohno/client` (the state_dir) will still be created but not
`/ohno/alloc` (the alloc_dir).
While I cannot think of a good reason why someone would want to embed
Nomad's client (and possibly server) directories in chroots, there
should be no cause for harm. chroots are only built when Nomad runs as
root, and Nomad disables running exec jobs as root by default. Therefore
even if client state is copied into chroots, it will be inaccessible to
tasks.
Skipping the `data_dir` and `{client,server}.state_dir` is possible, but
this PR attempts to implement the minimum viable solution to reduce risk
of unintended side effects or bugs.
When running tests as root in a vm without the fix, the following error
occurs:
```
=== RUN TestAllocDir_SkipAllocDir
alloc_dir_test.go:520:
Error Trace: alloc_dir_test.go:520
Error: Received unexpected error:
Couldn't create destination file /tmp/TestAllocDir_SkipAllocDir1457747331/001/nomad/test/testtask/nomad/test/testtask/.../nomad/test/testtask/secrets/.nomad-mount: open /tmp/TestAllocDir_SkipAllocDir1457747331/001/nomad/test/.../testtask/secrets/.nomad-mount: file name too long
Test: TestAllocDir_SkipAllocDir
--- FAIL: TestAllocDir_SkipAllocDir (22.76s)
```
Also removed unused Copy methods on AllocDir and TaskDir structs.
Thanks to @eveld for not letting me forget about this!
The Group Alloc watcher is an implementation of a PrevAllocWatcher that
can wait for multiple previous allocs before terminating.
This is to be used when running an allocation that is preempting upstream
allocations, and thus only supports being ran with a local alloc watcher.
It also currently requires all of its child watchers to correctly handle
context cancellation. Should this be a problem, it should be fairly easy
to implement a replacement using channels rather than a waitgroup.
It obeys the PrevAllocWatcher interface for convenience, but it may be
better to extract Migration capabilities into a seperate interface for
greater clarity.
The default job here contains some exec task config (for setting
command and args) that aren't used for mock driver. Now, the alloc
runner seems stricter about validating fields and errors on unexpected
fields.
Updating configs in tests so we can have an explicit task config
whenever driver is set explicitly.
* Stopping an alloc is implemented via Updates but update hooks are
*not* run.
* Destroying an alloc is a best effort cleanup.
* AllocRunner destroy hooks implemented.
* Disk migration and blocking on a previous allocation exiting moved to
its own package to avoid cycles. Now only depends on alloc broadcaster
instead of also using a waitch.
* AllocBroadcaster now only drops stale allocations and always keeps the
latest version.
* Made AllocDir safe for concurrent use
Lots of internal contexts that are currently unused. Unsure if they
should be used or removed.
