The drainer component is fairly complex. As part of upcoming work to fix some of
the drainer's rough edges, document the drainer's architecture from a Nomad
developer perspective.
Fixes#16517
Given a 3 Server cluster with at least 1 Client connected to Follower 1:
If a NodeMeta.{Apply,Read} for the Client request is received by
Follower 1 with `AllowStale = false` the Follower will forward the
request to the Leader.
The Leader, not being connected to the target Client, will forward the
RPC to Follower 1.
Follower 1, seeing AllowStale=false, will forward the request to the
Leader.
The Leader, not being connected to... well hoppefully you get the
picture: an infinite loop occurs.
* [no ci] use json for grouping packages for testing
* [no ci] able to get packages in group
* [no ci] able to run groups of tests
* [no ci] more
* [no ci] try disable circle unit tests
* ci: use actions/checkout@v3
* ci: rename to quick
* ci: need make dev in mods cache step
* ci: make compile step depend on checks step
* ci: bump consul and vault versions
* ci: need make dev for group tests
* ci: update ci unit testing docs
* docs: spell plumbing correctly
Co-authored-by: Tim Gross <tgross@hashicorp.com>
Co-authored-by: Tim Gross <tgross@hashicorp.com>
This changeset adds new architecture internals documents to the contributing
guide. These are intentionally here and not on the public-facing website because
the material is not required for operators and includes a lot of diagrams that
we can cheaply maintain with mermaid syntax but would involve art assets to have
up on the main site that would become quickly out of date as code changes happen
and be extremely expensive to maintain. However, these should be suitable to use
as points of conversation with expert end users.
Included:
* A description of Evaluation triggers and expected counts, with examples.
* A description of Evaluation states and implicit states. This is taken from an
internal document in our team wiki.
* A description of how writing the State Store works. This is taken from a
diagram I put together a few months ago for internal education purposes.
* A description of Evaluation lifecycle, from registration to running
Allocations. This is mostly lifted from @lgfa29's amazing mega-diagram, but
broken into digestible chunks and without multi-region deployments, which I'd
like to cover in a future doc.
Also includes adding Deployments to our public-facing glossary.
Co-authored-by: Luiz Aoqui <luiz@hashicorp.com>
Co-authored-by: Michael Schurter <mschurter@hashicorp.com>
Co-authored-by: Seth Hoenig <shoenig@duck.com>
This PR update to Go 1.18.2. Also update the versions of hclfmt
and go-hclogfmt which includes newer dependencies necessary for dealing
with go1.18.
The hcl v2 branch is now 'nomad-v2.9.1+tweaks2', to include a fix for
newer macOS versions: 8927e75e82
Adopts [`go-changelog`](https://github.com/hashicorp/go-changelog) for managing Nomad's changelog. `go-changelog` is becoming the HashiCorp defacto standard tool for managing changelog, e.g. [Consul](https://github.com/hashicorp/consul/pull/8387), [Vault](https://github.com/hashicorp/vault/pull/10363), [Waypoint](https://github.com/hashicorp/waypoint/pull/1179). [Consul](https://github.com/hashicorp/consul/pull/8387) seems to be the first product to adopt it, and its PR has the most context - though I've updated `.changelog/README.md` with the relevant info here.
## Changes to developers workflow
When opening PRs, developers should add a changelog entry in `.changelog/<PR#>.txt`. Check [`.changelog/README.md`](https://github.com/hashicorp/nomad/blob/docs-adopt-gochangelog/.changelog/README.md#developer-guide).
For the WIP release, entries can be amended even after the PR merged, and new files may be added post-hoc (e.g. during transition period, missed accidentally, community PRs, etc).
### Transitioning
Pending PRs can start including the changelog entry files immediately.
For 1.1.3/1.0.9 cycle, the release coordinator should create the entries for any PR that gets merged without a changelog entry file. They should also move any 1.1.3 entry in CHANGELOG.md to a changelog entry file, as this PR done for GH-10818.
## Changes to release process
Before cutting a release, release coordinator should update the changelog by inserting the output of `make changelog` to CHANGELOG.md with appropriate headers. See [`.changelog/README.md`](https://github.com/hashicorp/nomad/blob/docs-adopt-gochangelog/.changelog/README.md#how-to-generate-changelog-entries-for-release) for more details.
## Details
go-changelog is a basic templating engine for maintaining changelog in HashiCorp environment.
It expects the changelog entries as files indexed by their PR number. The CLI generates the changelog section for a release by comparing two git references (e.g. `HEAD` and the latest release, e.g. `v1.1.2`), and still requires manual process for updating CHANGELOG.md and final formatting.
The approach has many nice advantages:
* Avoids changelog related merge conflicts: Each PR touches different file!
* Copes with amendments and post-PR updates: Just add or update a changelog entry file using the original PR numbers.
* Addresses the release backporting scenario: Cherry-picking PRs will cherry-pick the relevant changelog entry automatically!
* Only relies on data available through `git` - no reliance on GitHub metadata or require GitHub credentials
The approach has few downsides though:
* CHANGELOG.md going stale during development and must be updated manually before cutting the release
* Repository watchers can no longer glance at the CHANGELOG.md to see upcoming changes
* We can periodically update the file, but `go-changelog` tool does not aid with that
* `go-changelog` tool does not offer good error reporting. If an entry is has an invalid tag (e.g. uses `release-note:bugfix` instead of `release-note:bug`), the entry will be dropped silently
* We should update go-changelog to warn against unexpected entry tags
* TODO: Meanwhile, PR reviewers and release coordinators should watch out
## Potential follow ups
We should follow up with CI checks to ensure PR changes include a warning. I've opted not to include that now. We still make many non-changelog-worth PRs for website/docs, for large features that get merged in multiple small PRs. I did not want to include a check that fails often.
Also, we should follow up to have `go-changelog` emit better warnings on unexpected tag.
node drain: use msgtype on txn so that events are emitted
wip: encoding extension to add Node.Drain field back to API responses
new approach for hiding Node.SecretID in the API, using `json` tag
documented this approach in the contributing guide
refactored the JSON handlers with extensions
modified event stream encoding to use the go-msgpack encoders with the extensions
This PR implements Nomad built-in support for running Consul Connect
terminating gateways. Such a gateway can be used by services running
inside the service mesh to access "legacy" services running outside
the service mesh while still making use of Consul's service identity
based networking and ACL policies.
https://www.consul.io/docs/connect/gateways/terminating-gateway
These gateways are declared as part of a task group level service
definition within the connect stanza.
service {
connect {
gateway {
proxy {
// envoy proxy configuration
}
terminating {
// terminating-gateway configuration entry
}
}
}
}
Currently Envoy is the only supported gateway implementation in
Consul. The gateay task can be customized by configuring the
connect.sidecar_task block.
When the gateway.terminating field is set, Nomad will write/update
the Configuration Entry into Consul on job submission. Because CEs
are global in scope and there may be more than one Nomad cluster
communicating with Consul, there is an assumption that any terminating
gateway defined in Nomad for a particular service will be the same
among Nomad clusters.
Gateways require Consul 1.8.0+, checked by a node constraint.
Closes#9445
Michael Schurter