* exec2: add client support for unveil filesystem isolation mode
This PR adds support for a new filesystem isolation mode, "Unveil". The
mode introduces a "alloc_mounts" directory where tasks have user-owned
directory structure which are bind mounts into the real alloc directory
structure. This enables a task driver to use landlock (and maybe the
real unveil on openbsd one day) to isolate a task to the task owned
directory structure, providing sandboxing.
* actually create alloc-mounts-dir directory
* fix doc strings about alloc mount dir paths
The `golang.org/x/net/context` package was merged into the stdlib as of go
1.7. Update the imports to use the identical stdlib version. Clean up import
blocks for the impacted files to remove unnecessary package aliasing.
* driver: fix integer conversion error
The shared executor incorrectly parsed the user's group into int32 and
then cast to uint32 without bounds checking. This is harmless because
an out-of-bounds gid will throw an error later, but it triggers
security and code quality scans. Parse directly to uint32 so that we
get correct error handling.
* helper: fix integer conversion error
The autopilot flags helper incorrectly parses a uint64 to a uint which
is machine specific size. Although we don't have 32-bit builds, this
sets off security and code quality scaans. Parse to the machine sized
uint.
* driver: restrict bounds of port map
The plugin server doesn't constrain the maximum integer for port
maps. This could result in a user-visible misconfiguration, but it
also triggers security and code quality scans. Restrict the bounds
before casting to int32 and return an error.
* cpuset: restrict upper bounds of cpuset values
Our cpuset configuration expects values in the range of uint16 to
match the expectations set by the kernel, but we don't constrain the
values before downcasting. An underflow could lead to allocations
failing on the client rather than being caught earlier. This also make
security and code quality scanners happy.
* http: fix integer downcast for per_page parameter
The parser for the `per_page` query parameter downcasts to int32
without bounds checking. This could result in underflow and
nonsensical paging, but there's no server-side consequences for
this. Fixing this will silence some security and code quality scanners
though.
Add a new hostname string parameter to the network block which
allows operators to specify the hostname of the network namespace.
Changing this causes a destructive update to the allocation and it
is omitted if empty from API responses. This parameter also supports
interpolation.
In order to have a hostname passed as a configuration param when
creating an allocation network, the CreateNetwork func of the
DriverNetworkManager interface needs to be updated. In order to
minimize the disruption of future changes, rather than add another
string func arg, the function now accepts a request struct along with
the allocID param. The struct has the hostname as a field.
The in-tree implementations of DriverNetworkManager.CreateNetwork
have been modified to account for the function signature change.
In updating for the change, the enhancement of adding hostnames to
network namespaces has also been added to the Docker driver, whilst
the default Linux manager does not current implement it.
Add a new driver capability: RemoteTasks.
When a task is run by a driver with RemoteTasks set, its TaskHandle will
be propagated to the server in its allocation's TaskState. If the task
is replaced due to a down node or draining, its TaskHandle will be
propagated to its replacement allocation.
This allows tasks to be scheduled in remote systems whose lifecycles are
disconnected from the Nomad node's lifecycle.
See https://github.com/hashicorp/nomad-driver-ecs for an example ECS
remote task driver.
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.
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 plumbs the plugins done ctx through the base and driver plugin
clients (device already had it). Further, it adds generic handling of
gRPC stream errors.
Driver plugin framework to facilitate development of driver plugins.
Implementing plugins only need to implement the DriverPlugin interface.
The framework proxies this interface to the go-plugin GRPC interface generated
from the driver.proto spec.
A testing harness is provided to allow implementing drivers to test the full
lifecycle of the driver plugin. An example use:
func TestMyDriver(t *testing.T) {
harness := NewDriverHarness(t, &MyDiverPlugin{})
// The harness implements the DriverPlugin interface and can be used as such
taskHandle, err := harness.StartTask(...)
}
