This PR removes locking around commonly accessed node attributes that do
not need to be locked. The locking could cause nodes to TTL as the
heartbeat code path was acquiring a lock that could be held for an
excessively long time. An example of this is when Vault is inaccessible,
since the fingerprint is run with a lock held but the Vault
fingerprinter makes the API calls with a large timeout.
Fixes https://github.com/hashicorp/nomad/issues/2689
interface has 3 implementations:
1. local for blocking and moving data locally
2. remote for blocking and moving data from another node
3. noop for allocs that don't need to block
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.
This PR takes the host ID and runs it through a hash so that it is well
distributed. This makes it so that machines that report similar host IDs
are easily distinguished.
Instances of similar IDs occur on EC2 where the ID is prefixed and on
motherboards created in the same batch.
Fixes https://github.com/hashicorp/nomad/issues/2534
This PR adds tracking to when a task starts and finishes and the logs
API takes advantage of this and returns better errors when asking for
logs that do not exist.
Michael Schurter