Log lines which include an error should use the full term "error"
as the context key. This provides consistency across the codebase
and avoids a Go style which operators might not be aware of.
This PR modifies raw_exec and exec to ensure the cgroup for a task
they are driving still exists during a task restart. These drivers
have the same bug but with different root cause.
For raw_exec, we were removing the cgroup in 2 places - the cpuset
manager, and in the unix containment implementation (the thing that
uses freezer cgroup to clean house). During a task restart, the
containment would remove the cgroup, and when the task runner hooks
went to start again would block on waiting for the cgroup to exist,
which will never happen, because it gets created by the cpuset manager
which only runs as an alloc pre-start hook. The fix here is to simply
not delete the cgroup in the containment implementation; killing the
PIDs is enough. The removal happens in the cpuset manager later anyway.
For exec, it's the same idea, except DestroyTask is called on task
failure, which in turn calls into libcontainer, which in turn deletes
the cgroup. In this case we do not have control over the deletion of
the cgroup, so instead we hack the cgroup back into life after the
call to DestroyTask.
All of this only applies to cgroups v2.
This test exercises upgrades between 0.8 and Nomad versions greater
than 0.9. We have not supported 0.8.x in a very long time and in any
case the test has been marked to skip because the downloader doesn't
work.
This PR introduces support for using Nomad on systems with cgroups v2 [1]
enabled as the cgroups controller mounted on /sys/fs/cgroups. Newer Linux
distros like Ubuntu 21.10 are shipping with cgroups v2 only, causing problems
for Nomad users.
Nomad mostly "just works" with cgroups v2 due to the indirection via libcontainer,
but not so for managing cpuset cgroups. Before, Nomad has been making use of
a feature in v1 where a PID could be a member of more than one cgroup. In v2
this is no longer possible, and so the logic around computing cpuset values
must be modified. When Nomad detects v2, it manages cpuset values in-process,
rather than making use of cgroup heirarchy inheritence via shared/reserved
parents.
Nomad will only activate the v2 logic when it detects cgroups2 is mounted at
/sys/fs/cgroups. This means on systems running in hybrid mode with cgroups2
mounted at /sys/fs/cgroups/unified (as is typical) Nomad will continue to
use the v1 logic, and should operate as before. Systems that do not support
cgroups v2 are also not affected.
When v2 is activated, Nomad will create a parent called nomad.slice (unless
otherwise configured in Client conifg), and create cgroups for tasks using
naming convention <allocID>-<task>.scope. These follow the naming convention
set by systemd and also used by Docker when cgroups v2 is detected.
Client nodes now export a new fingerprint attribute, unique.cgroups.version
which will be set to 'v1' or 'v2' to indicate the cgroups regime in use by
Nomad.
The new cpuset management strategy fixes#11705, where docker tasks that
spawned processes on startup would "leak". In cgroups v2, the PIDs are
started in the cgroup they will always live in, and thus the cause of
the leak is eliminated.
[1] https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.htmlCloses#11289Fixes#11705#11773#11933
This changeset does not introduce any functional change for the
docker driver, but rather cleans up the implementation around
computing configured capabilities by re-using code written for
the exec/java task drivers.
This PR enables setting allow_caps on the exec driver
plugin configuration, as well as cap_add and cap_drop in
exec task configuration. These options replicate the
functionality already present in the docker task driver.
Important: this change also reduces the default set of
capabilities enabled by the exec driver to match the
default set enabled by the docker driver. Until v1.0.5
the exec task driver would enable all capabilities supported
by the operating system. v1.0.5 removed NET_RAW from that
list of default capabilities, but left may others which
could potentially also be leveraged by compromised tasks.
Important: the "root" user is still special cased when
used with the exec driver. Older versions of Nomad enabled
enabled all capabilities supported by the operating system
for tasks set with the root user. To maintain compatibility
with existing clusters we continue supporting this "feature",
however we maintain support for the legacy set of capabilities
rather than enabling all capabilities now supported on modern
operating systems.
This PR adds pid_mode and ipc_mode options to the exec and java task
driver config options. By default these will defer to the default_pid_mode
and default_ipc_mode agent plugin options created in #9969. Setting
these values to "host" mode disables isolation for the task. Doing so
is not recommended, but may be necessary to support legacy job configurations.
Closes#9970
This PR adds default_pid_mode and default_ipc_mode options to the exec and java
task drivers. By default these will default to "private" mode, enabling PID and
IPC isolation for tasks. Setting them to "host" mode disables isolation. Doing
so is not recommended, but may be necessary to support legacy job configurations.
Closes#9969
This fixes few cases where driver eventor goroutines are leaked during
normal operations, but especially so in tests.
This change makes few modifications:
First, it switches drivers to use `Context`s to manage shutdown events.
Previously, it relied on callers invoking `.Shutdown()` function that is
specific to internal drivers only and require casting. Using `Contexts`
provide a consistent idiomatic way to manage lifecycle for both internal
and external drivers.
Also, I discovered few places where we don't clean up a temporary driver
instance in the plugin catalog code, where we dispense a driver to
inspect and validate the schema config without properly cleaning it up.
When an allocation runs for a task driver that can't support volume mounts,
the mounting will fail in a way that can be hard to understand. With host
volumes this usually means failing silently, whereas with CSI the operator
gets inscrutable internals exposed in the `nomad alloc status`.
This changeset adds a MountConfig field to the task driver Capabilities
response. We validate this when the `csi_hook` or `volume_hook` fires and
return a user-friendly error.
Note that we don't currently have a way to get driver capabilities up to the
server, except through attributes. Validating this when the user initially
submits the jobspec would be even better than what we're doing here (and could
be useful for all our other capabilities), but that's out of scope for this
changeset.
Also note that the MountConfig enum starts with "supports all" in order to
support community plugins in a backwards compatible way, rather than cutting
them off from volume mounting unexpectedly.
Looks like the RecoverTask doesn't set taskHandle.logger field causing
a panic when the handle attempts to log (e.g. when Shutdown or Signaling
fails).
* master: (23 commits)
tests: avoid assertion in goroutine
spell check
ci: run checkscripts
tests: deflake TestRktDriver_StartWaitRecoverWaitStop
drivers/rkt: Remove unused github.com/rkt/rkt
drivers/rkt: allow development on non-linux
cli: Hide `nomad docker_logger` from help output
api: test api and structs are in sync
goimports until make check is happy
nil check node resources to prevent panic
tr: use context in as select statement
move pluginutils -> helper/pluginutils
vet
goimports
gofmt
Split hclspec
move hclutils
Driver tests do not use hcl2/hcl, hclspec, or hclutils
move reattach config
loader and singleton
...
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
This PR fixes various instances of plugins being launched without using
the parent loggers. This meant that logs would not all go to the same
output, break formatting etc.
Re-export the ResourceUsage structs in drivers package to avoid drivers
directly depending on the internal client/structs package directly.
I attempted moving the structs to drivers, but that caused some import
cycles that was a bit hard to disentagle. Alternatively, I added an
alias here that's sufficient for our purposes of avoiding external
drivers depend on internal packages, while allowing us to restructure
packages in future without breaking source compatibility.
This implements the InternalPluginDriver interface in each driver, and
calls the cancellation fn for their respective eventers.
This fixes a per task goroutine leak during test suite execution.
