This PR fixes a bug where sidecar services would be re-registered into Consul every ~30
seconds, caused by the parent service having its tags field set and the sidecar_service
tags unset. Nomad would directly compare the tags between its copy of the sidecar service
definition and the tags of the sidecar service reported by Consul. This does not work,
because Consul will under-the-hood set the sidecar service tags to inherit the parent
service tags if the sidecar service tags are unset. The comparison then done by Nomad
would not match, if the parent sidecar tags are set.
Fixes#10025
Previously, connect sidecars would be re-registered with consul every cycle
of Nomad's reconciliation loop around Consul service registrations. This is
because part of the comparison used `reflect.DeepEqual` on []string objects,
which returns false when one object is `[]string{}` and the other is `[]string{}(nil)`.
Unforunately, this was always the case, and every Connect sidecar service
would be re-registered on every iteration, which happens every 30 seconds.
As newer versions of Consul are released, the minimum version of Envoy
it supports as a sidecar proxy also gets bumped. Starting with the upcoming
Consul v1.9.X series, Envoy v1.11.X will no longer be supported. Current
versions of Nomad hardcode a version of Envoy v1.11.2 to be used as the
default implementation of Connect sidecar proxy.
This PR introduces a change such that each Nomad Client will query its
local Consul for a list of Envoy proxies that it supports (https://github.com/hashicorp/consul/pull/8545)
and then launch the Connect sidecar proxy task using the latest supported version
of Envoy. If the `SupportedProxies` API component is not available from
Consul, Nomad will fallback to the old version of Envoy supported by old
versions of Consul.
Setting the meta configuration option `meta.connect.sidecar_image` or
setting the `connect.sidecar_task` stanza will take precedence as is
the current behavior for sidecar proxies.
Setting the meta configuration option `meta.connect.gateway_image`
will take precedence as is the current behavior for connect gateways.
`meta.connect.sidecar_image` and `meta.connect.gateway_image` may make
use of the special `${NOMAD_envoy_version}` variable interpolation, which
resolves to the newest version of Envoy supported by the Consul agent.
Addresses #8585#7665
2020-10-13 09:14:12 -05:00
Renamed from command/agent/consul/client_test.go (Browse further)
Seth Hoenig