This PR changes Nomad's wrapper around the Consul NamespaceAPI so that
it will detect if the Consul Namespaces feature is enabled before making
a request to the Namespaces API. Namespaces are not enabled in Consul OSS,
and require a suitable license to be used with Consul ENT.
Previously Nomad would check for a 404 status code when makeing a request
to the Namespaces API to "detect" if Consul OSS was being used. This does
not work for Consul ENT with Namespaces disabled, which returns a 500.
Now we avoid requesting the namespace API altogether if Consul is detected
to be the OSS sku, or if the Namespaces feature is not licensed. Since
Consul can be upgraded from OSS to ENT, or a new license applied, we cache
the value for 1 minute, refreshing on demand if expired.
Fixes https://github.com/hashicorp/nomad-enterprise/issues/575
Note that the ticket originally describes using attributes from https://github.com/hashicorp/nomad/issues/10688.
This turns out not to be possible due to a chicken-egg situation between
bootstrapping the agent and setting up the consul client. Also fun: the
Consul fingerprinter creates its own Consul client, because there is no
[currently] no way to pass the agent's client through the fingerprint factory.
Track usage of incoming streams on a connection. Connections without
reference counts get marked as unused and reaped in a periodic job.
This fixes a bug where `alloc exec` and `alloc fs` sessions get terminated
unexpectedly. Previously, when a client heartbeats switches between
servers, the pool connection reaper eventually identifies the connection
as unused and closes it even if it has an active exec/fs sessions.
Fixes#10579
This PR fixes the API to _not_ set the default mesh gateway mode. Before,
the mode would be set to "none" in Canonicalize, which is incorrect. We
should pass through the empty string so that folks can make use of Consul
service-defaults Config entries to configure the default mode.
This PR implements first-class support for Nomad running Consul
Connect Mesh Gateways. Mesh gateways enable services in the Connect
mesh to make cross-DC connections via gateways, where each datacenter
may not have full node interconnectivity.
Consul docs with more information:
https://www.consul.io/docs/connect/gateways/mesh-gateway
The following group level service block can be used to establish
a Connect mesh gateway.
service {
connect {
gateway {
mesh {
// no configuration
}
}
}
}
Services can make use of a mesh gateway by configuring so in their
upstream blocks, e.g.
service {
connect {
sidecar_service {
proxy {
upstreams {
destination_name = "<service>"
local_bind_port = <port>
datacenter = "<datacenter>"
mesh_gateway {
mode = "<mode>"
}
}
}
}
}
}
Typical use of a mesh gateway is to create a bridge between datacenters.
A mesh gateway should then be configured with a service port that is
mapped from a host_network configured on a WAN interface in Nomad agent
config, e.g.
client {
host_network "public" {
interface = "eth1"
}
}
Create a port mapping in the group.network block for use by the mesh
gateway service from the public host_network, e.g.
network {
mode = "bridge"
port "mesh_wan" {
host_network = "public"
}
}
Use this port label for the service.port of the mesh gateway, e.g.
service {
name = "mesh-gateway"
port = "mesh_wan"
connect {
gateway {
mesh {}
}
}
}
Currently Envoy is the only supported gateway implementation in Consul.
By default Nomad client will run the latest official Envoy docker image
supported by the local Consul agent. The Envoy task can be customized
by setting `meta.connect.gateway_image` in agent config or by setting
the `connect.sidecar_task` block.
Gateways require Consul 1.8.0+, enforced by the Nomad scheduler.
Closes#9446
When `nomad volume create` was introduced in Nomad 1.1.0, we changed the
volume spec to take a list of capabilities rather than a single capability, to
meet the requirements of the CSI spec. When a volume is registered via `nomad
volume register`, we should be using the same fields to validate the volume
with the controller plugin.
This PR adds two additional constraints on Connect sidecar and gateway tasks,
making sure Nomad schedules them only onto nodes where Connect is actually
enabled on the Consul agent.
Consul requires `connect.enabled = true` and `ports.grpc = <number>` to be
explicitly set on agent configuration before Connect APIs will work. Until
now, Nomad would only validate a minimum version of Consul, which would cause
confusion for users who try to run Connect tasks on nodes where Consul is not
yet sufficiently configured. These contstraints prevent job scheduling on nodes
where Connect is not actually use-able.
Closes#10700
Explicitly set the `oom_score_adj` value for `exec` and `java` tasks.
We recommend that the Nomad service to have oom_score_adj of a low value
(e.g. -1000) to avoid having nomad agent OOM Killed if the node is
oversubscriped.
However, Nomad's workloads should not inherit Nomad's process, which is
the default behavior.
Fixes#10663
This PR adds new probes for detecting these new Consul related attributes:
Consul namespaces are a Consul enterprise feature that may be disabled depending
on the enterprise license associated with the Consul servers. Having this attribute
available will enable Nomad to properly decide whether to query the Consul Namespace
API.
Consul connect must be explicitly enabled before Connect APIs will work. Currently
Nomad only checks for a minimum Consul version. Having this attribute available will
enable Nomad to properly schedule Connect tasks only on nodes with a Consul agent that
has Connect enabled.
Consul connect requires the grpc port to be explicitly set before Connect APIs will work.
Currently Nomad only checks for a minimal Consul version. Having this attribute available
will enable Nomad to schedule Connect tasks only on nodes with a Consul agent that has
the grpc listener enabled.
This PR refactors the ConsulFingerprint implementation, breaking individual attributes
into individual functions to make testing them easier. This is in preparation for
additional extractors about to be added. Behavior should be otherwise unchanged.
It adds the attribute consul.sku, which can be used to differentiate between Consul
OSS vs Consul ENT.
The reconciler has some complicated behavior when there are already running
allocations from a previous version of the job that we want to keep, as
happens during a rollback. Document this behavior with a test.
The plans generated by the scheduler produce high-level output of counts on each
evaluation, but when debugging scheduler issues it'd be nice to have a more
detailed view of the resulting plan. Emitting this log at trace minimizes the
overhead, and producing it in the plan applyer makes it easier to find as it
will always be on the leader.
Arguments to our logger's various write methods are evaluated eagerly, so
method calls in log parameters will always be called, regardless of log
level. Move some logger messages to the logger's `Fmt` method so that
`GoString` is evaluated lazily instead.
Ease spinning up a cluster, where binaries are fetched from arbitrary
urls. These could be CircleCI `build-binaries` job artifacts, or
presigned S3 urls.
Co-authored-by: Tim Gross <tgross@hashicorp.com>
refactor the api handling of `nomad exec`, and ensure that we process
all received events before handling websocket closing.
The exit code should be the last message received, and we ought to
ignore any websocket close error we receive afterwards.
Previously, we used two channels: one for websocket frames and another
for handling errors. This raised the possibility that we processed the
error before processing the frames, resulting into an "unexpected EOF"
error.
