In systemd-resolved hosts with no DNS customizations, the docker driver
DNS setting should be compared to /run/systemd/resolve/resolv.conf while
exec/java drivers should be compared to /etc/resolv.conf.
When system-resolved is enabled, /etc/resolv.conf is a stub that points
to 127.0.0.53. Docker avoids this stub because this address isn't
accessible from the container. The exec/java drivers that don't create
network isolations use the stub though in the default configuration.
* docker: support group allocated ports
* docker: add new ports driver config to specify which group ports are mapped
* docker: update port mapping docs
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.
Operators commonly have docker logs aggregated using various tools and
don't need nomad to manage their docker logs. Worse, Nomad uses a
somewhat heavy docker api call to collect them and it seems to cause
problems when a client runs hundreds of log collections.
Here we add a knob to disable log aggregation completely for nomad.
When log collection is disabled, we avoid running logmon and
docker_logger for the docker tasks in this implementation.
The downside here is once disabled, `nomad logs ...` commands and API
no longer return logs and operators must corrolate alloc-ids with their
aggregated log info.
This is meant as a stop gap measure. Ideally, we'd follow up with at
least two changes:
First, we should optimize behavior when we can such that operators don't
need to disable docker log collection. Potentially by reverting to
using pre-0.9 syslog aggregation in linux environments, though with
different trade-offs.
Second, when/if logs are disabled, nomad logs endpoints should lookup
docker logs api on demand. This ensures that the cost of log collection
is paid sparingly.
This commit introduces support for configuring mount propagation when
mounting volumes with the `volume_mount` stanza on Linux targets.
Similar to Kubernetes, we expose 3 options for configuring mount
propagation:
- private, which is equivalent to `rprivate` on Linux, which does not allow the
container to see any new nested mounts after the chroot was created.
- host-to-task, which is equivalent to `rslave` on Linux, which allows new mounts
that have been created _outside of the container_ to be visible
inside the container after the chroot is created.
- bidirectional, which is equivalent to `rshared` on Linux, which allows both
the container to see new mounts created on the host, but
importantly _allows the container to create mounts that are
visible in other containers an don the host_
private and host-to-task are safe, but bidirectional mounts can be
dangerous, as if the code inside a container creates a mount, and does
not clean it up before tearing down the container, it can cause bad
things to happen inside the kernel.
To add a layer of safety here, we require that the user has ReadWrite
permissions on the volume before allowing bidirectional mounts, as a
defense in depth / validation case, although creating mounts should also require
a priviliged execution environment inside the container.
NetIsolationModes and MustInitiateNetwork were left out of the
driver Capabilities when using an external task driver plugin
Signed-off-by: Lucas BEE <pouulet@gmail.com>
Adds a new Prerun and Postrun hooks to manage set up of network namespaces
on linux. Work still needs to be done to make the code platform agnostic and
support Docker style network initalization.
The driver plugin stub client must call `grpcutils.HandleGrpcErr` to handle plugin
shutdown similar to other functions. This ensures that TaskStats returns
`ErrPluginShutdown` when plugin shutdown.
In this commit, we add two driver interfaces for supporting `nomad exec`
invocation:
* A high level `ExecTaskStreamingDriver`, that operates on io reader/writers.
Drivers should prefer using this interface
* A low level `ExecTaskStreamingRawDriver` that operates on the raw stream of
input structs; useful when a driver delegates handling to driver backend (e.g.
across RPC/grpc).
The interfaces are optional for a driver, as `nomad exec` support is opt-in.
Existing drivers continue to compile without exec support, until their
maintainer add such support.
Furthermore, we create protobuf structures to represent exec stream entities:
`ExecTaskStreamingRequest` and `ExecTaskStreamingResponse`. We aim to reuse the
protobuf generated code as much as possible, without translation to avoid
conversion overhead.
`ExecTaskStream` abstract fetching and sending stream entities. It's influenced
by the grpc bi-directional stream interface, to avoid needing any adapter. I
considered using channels, but the asynchronisity and concurrency makes buffer
reuse too complicated, which would put more pressure on GC and slows exec operation.
Fix a case where TotalTicks doesn't get serialized across executor grpc
calls.
Here, I opted to implicit add field, rather than explicitly mark it as a
measured field, because it's a derived field and to preserve 0.8
behavior where total ticks aren't explicitly marked as a measured field.
Noticed that the protobuf files are out of sync with ones generated by 1.2.0 protoc go plugin.
The cause for these files seem to be related to release processes, e.g. [0.9.0-beta1 preperation](ecec3d38de (diff-da4da188ee496377d456025c2eab4e87)), and [0.9.0-beta3 preperation](b849d84f2f).
This restores the changes to that of the pinned protoc version and fails build if protobuf files are out of sync. Sample failing Travis job is that of the first commit change: https://travis-ci.org/hashicorp/nomad/jobs/506285085
As far as I can tell this is the most straightforward and resilient way
to skip error logging on context cancellation with grpc streams. You
cannot compare the error against context.Canceled directly as it is of
type `*status.statusError`. The next best solution I found was:
```go
resp, err := stream.Recv()
if code, ok := err.(interface{ Code() code.Code }); ok {
if code.Code == code.Canceled {
return
}
}
```
However I think checking ctx.Err() directly makes the code much easier
to read and is resilient against grpc API changes.
Track current memory usage, `memory.usage_in_bytes`, in addition to
`memory.max_memory_usage_in_bytes` and friends. This number is closer
what Docker reports.
Related to https://github.com/hashicorp/nomad/issues/5165 .
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
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.
* master: (71 commits)
Fix output of 'nomad deployment fail' with no arg
Always create a running allocation when testing task state
tests: ensure exec tests pass valid task resources (#4992)
some changes for more idiomatic code
fix iops related tests
fixed bug in loop delay
gofmt
improved code for readability
client: updateAlloc release lock after read
fixup! device attributes in `nomad node status -verbose`
drivers/exec: support device binds and mounts
fix iops bug and increase test matrix coverage
tests: tag image explicitly
changelog
ci: install lxc-templates explicitly
tests: skip checking rdma cgroup
ci: use Ubuntu 16.04 (Xenial) in TravisCI
client: update driver info on new fingerprint
drivers/docker: enforce volumes.enabled (#4983)
client: Style: use fluent style for building loggers
...
IOPS have been modelled as a resource since Nomad 0.1 but has never
actually been detected and there is no plan in the short term to add
detection. This is because IOPS is a bit simplistic of a unit to define
the performance requirements from the underlying storage system. In its
current state it adds unnecessary confusion and can be removed without
impacting any users. This PR leaves IOPS defined at the jobspec parsing
level and in the api/ resources since these are the two public uses of
the field. These should be considered deprecated and only exist to allow
users to stop using them during the Nomad 0.9.x release. In the future,
there should be no expectation that the field will exist.
this allows us to drop a cyclical import, but is subobptimal as it
requires BaseDriver tests to move. This falls firmly into the realm of
being a hack. Alternatives welcome.
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.
Yoan Blanc