The way the copying was happening on the alloc_runner was by temporarily
setting the alloc.Job to nil, copying and then restoring it. This
created an issue in which when the alloc was shared (which it is in
server/client mode and between alloc_runner/task_runner) there were race
conditions that could create a panic.
Fixes https://github.com/hashicorp/nomad/issues/2605
The Vault API returns a nil secret and nil error when reading an object
that doesn't exist. The old code assumed an error would be returned and
thus will panic when trying to validate a non-existant role.
This PR removes deepcopying of the job attached to the allocation in the
alloc runner. This operation is called very often so removing reflect
from the code path and the potentially large number of mallocs need to
create a job reduced memory and cpu pressure.
Previously was interpolating the original task's services again.
Fixes#2180
Also fixes a slight memory leak in the new consul agent. Script check
handles weren't being deleted after cancellation.
Fixes#2478#2474#1995#2294
The new client only handles agent and task service advertisement. Server
discovery is mostly unchanged.
The Nomad client agent now handles all Consul operations instead of the
executor handling task related operations. When upgrading from an
earlier version of Nomad existing executors will be told to deregister
from Consul so that the Nomad agent can re-register the task's services
and checks.
Drivers - other than qemu - now support an Exec method for executing
abritrary commands in a task's environment. This is used to implement
script checks.
Interfaces are used extensively to avoid interacting with Consul in
tests that don't assert any Consul related behavior.
