This commit causes sync to skip deregistering checks that are not
managed by nomad, such as service maintenance mode checks. This is
handled in the same way as service registrations - by doing a Nomad
specific prefix match.
The current implementation of Service Registration uses a hash of the
nomad-internal state of a service to register it with Consul, this means that
any update to the service invalidates this name and we then deregister, and
recreate the service in Consul.
While this behaviour slightly simplifies reasoning about service registration,
this becomes problematic when we add consul health checks to a service. When
the service is re-registered, so are the checks, which default to failing for
at least one check period.
This commit migrates us to using a stable identifier based on the
allocation, task, and service identifiers, and uses the difference
between the remote and local state to decide when to push updates.
It uses the existing hashing mechanic to decide when UpdateTask should
regenerate service registrations for providing to Sync, but this should
be removable as part of a future refactor.
It additionally introduces the _nomad-check- prefix for check
definitions, to allow for future allowing of consul features like
maintenance mode.
- Rewrote overview description
- Reformatted "Community" scetion for consistency with GitHub
- Removed IRC (redundant with Gitter)
- Added "Community Calls" section with links to prior sessions
- Added "Webinar" section with links to prior sessions
- Revised Bug Tracker copy
- Renamed "Tools for Provisioning & Experimentation" to "How to Install Nomad" section
- Bumped up the "How to Install Nomad" section right below to second on the list "Community"
- Removed "Videos" & "Blog Posts" section in favor of accurate segmentation between user talks, webinars, blog posts
- Added "Who Uses Nomad" section in consistency with new GitHub ReadME
- Removed the "Trusted By" section and disclaimer at bottom
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.
This adds `alloc-exec` capability to allow operator to execute command into a
running task. Furthermore, it adds `alloc-node-exec` capability, required when
the alloc task is raw_exec or a driver with no FSIsolation.
* client/metrics: modified metrics to use (updated) client copy of allocation instead of (unupdated) server copy
* updated armon/go-metrics to address race condition in DisplayMetrics
This helper returns the token as well as the ACL policy, to be used in a later
commit for logging the token info associated with nomad exec invocation.
Mahmood Ali