CSI plugins can require credentials for some publishing and
unpublishing workflow RPCs. Secrets are configured at the time of
volume registration, stored in the volume struct, and then passed
around as an opaque map by Nomad to the plugins.
When `nomad job inspect` encodes the response, if the decoded JSON
from the API doesn't exactly match the API struct, the field value
will be omitted even if it has a value. We only want the JSON struct
tag to `omitempty`.
Part of #6120
Building on the support for enabling connect proxy paths in #7323, this change
adds the ability to configure the 'service.check.expose' flag on group-level
service check definitions for services that are connect-enabled. This is a slight
deviation from the "magic" that Consul provides. With Consul, the 'expose' flag
exists on the connect.proxy stanza, which will then auto-generate expose paths
for every HTTP and gRPC service check associated with that connect-enabled
service.
A first attempt at providing similar magic for Nomad's Consul Connect integration
followed that pattern exactly, as seen in #7396. However, on reviewing the PR
we realized having the `expose` flag on the proxy stanza inseperably ties together
the automatic path generation with every HTTP/gRPC defined on the service. This
makes sense in Consul's context, because a service definition is reasonably
associated with a single "task". With Nomad's group level service definitions
however, there is a reasonable expectation that a service definition is more
abstractly representative of multiple services within the task group. In this
case, one would want to define checks of that service which concretely make HTTP
or gRPC requests to different underlying tasks. Such a model is not possible
with the course `proxy.expose` flag.
Instead, we now have the flag made available within the check definitions themselves.
By making the expose feature resolute to each check, it is possible to have
some HTTP/gRPC checks which make use of the envoy exposed paths, as well as
some HTTP/gRPC checks which make use of some orthongonal port-mapping to do
checks on some other task (or even some other bound port of the same task)
within the task group.
Given this example,
group "server-group" {
network {
mode = "bridge"
port "forchecks" {
to = -1
}
}
service {
name = "myserver"
port = 2000
connect {
sidecar_service {
}
}
check {
name = "mycheck-myserver"
type = "http"
port = "forchecks"
interval = "3s"
timeout = "2s"
method = "GET"
path = "/classic/responder/health"
expose = true
}
}
}
Nomad will automatically inject (via job endpoint mutator) the
extrapolated expose path configuration, i.e.
expose {
path {
path = "/classic/responder/health"
protocol = "http"
local_path_port = 2000
listener_port = "forchecks"
}
}
Documentation is coming in #7440 (needs updating, doing next)
Modifications to the `countdash` examples in https://github.com/hashicorp/demo-consul-101/pull/6
which will make the examples in the documentation actually runnable.
Will add some e2e tests based on the above when it becomes available.
Enable configuration of HTTP and gRPC endpoints which should be exposed by
the Connect sidecar proxy. This changeset is the first "non-magical" pass
that lays the groundwork for enabling Consul service checks for tasks
running in a network namespace because they are Connect-enabled. The changes
here provide for full configuration of the
connect {
sidecar_service {
proxy {
expose {
paths = [{
path = <exposed endpoint>
protocol = <http or grpc>
local_path_port = <local endpoint port>
listener_port = <inbound mesh port>
}, ... ]
}
}
}
stanza. Everything from `expose` and below is new, and partially implements
the precedent set by Consul:
https://www.consul.io/docs/connect/registration/service-registration.html#expose-paths-configuration-reference
Combined with a task-group level network port-mapping in the form:
port "exposeExample" { to = -1 }
it is now possible to "punch a hole" through the network namespace
to a specific HTTP or gRPC path, with the anticipated use case of creating
Consul checks on Connect enabled services.
A future PR may introduce more automagic behavior, where we can do things like
1) auto-fill the 'expose.path.local_path_port' with the default value of the
'service.port' value for task-group level connect-enabled services.
2) automatically generate a port-mapping
3) enable an 'expose.checks' flag which automatically creates exposed endpoints
for every compatible consul service check (http/grpc checks on connect
enabled services).
- tg.Count defaults to tg.Scaling.Min if present (falls back on previous default of 1 if Scaling is absent)
- Validate() enforces tg.Scaling.Min <= tg.Count <= tg.Scaling.Max
modification in ApiScalingPolicyToStructs, api.TaskGroup.Validate so that defaults are handled for TaskGroup.Count and
Add mount_options to both the volume definition on registration and to the volume block in the group where the volume is requested. If both are specified, the options provided in the request replace the options defined in the volume. They get passed to the NodePublishVolume, which causes the node plugin to actually mount the volume on the host.
Individual tasks just mount bind into the host mounted volume (unchanged behavior). An operator can mount the same volume with different options by specifying it twice in the group context.
closes#7007
* nomad/structs/volumes: add MountOptions to volume request
* jobspec/test-fixtures/basic.hcl: add mount_options to volume block
* jobspec/parse_test: add expected MountOptions
* api/tasks: add mount_options
* jobspec/parse_group: use hcl decode not mapstructure, mount_options
* client/allocrunner/csi_hook: pass MountOptions through
client/allocrunner/csi_hook: add a VolumeMountOptions
client/allocrunner/csi_hook: drop Options
client/allocrunner/csi_hook: use the structs options
* client/pluginmanager/csimanager/interface: UsageOptions.MountOptions
* client/pluginmanager/csimanager/volume: pass MountOptions in capabilities
* plugins/csi/plugin: remove todo 7007 comment
* nomad/structs/csi: MountOptions
* api/csi: add options to the api for parsing, match structs
* plugins/csi/plugin: move VolumeMountOptions to structs
* api/csi: use specific type for mount_options
* client/allocrunner/csi_hook: merge MountOptions here
* rename CSIOptions to CSIMountOptions
* client/allocrunner/csi_hook
* client/pluginmanager/csimanager/volume
* nomad/structs/csi
* plugins/csi/fake/client: add PrevVolumeCapability
* plugins/csi/plugin
* client/pluginmanager/csimanager/volume_test: remove debugging
* client/pluginmanager/csimanager/volume: fix odd merging logic
* api: rename CSIOptions -> CSIMountOptions
* nomad/csi_endpoint: remove a 7007 comment
* command/alloc_status: show mount options in the volume list
* nomad/structs/csi: include MountOptions in the volume stub
* api/csi: add MountOptions to stub
* command/volume_status_csi: clean up csiVolMountOption, add it
* command/alloc_status: csiVolMountOption lives in volume_csi_status
* command/node_status: display mount flags
* nomad/structs/volumes: npe
* plugins/csi/plugin: npe in ToCSIRepresentation
* jobspec/parse_test: expand volume parse test cases
* command/agent/job_endpoint: ApiTgToStructsTG needs MountOptions
* command/volume_status_csi: copy paste error
* jobspec/test-fixtures/basic: hclfmt
* command/volume_status_csi: clean up csiVolMountOption
* command/agent/csi_endpoint: support type filter in volumes & plugins
* command/agent/http: use /v1/volume/csi & /v1/plugin/csi
* api/csi: use /v1/volume/csi & /v1/plugin/csi
* api/nodes: use /v1/volume/csi & /v1/plugin/csi
* api/nodes: not /volumes/csi, just /volumes
* command/agent/csi_endpoint: fix ot parameter parsing
* api/allocations: GetTaskGroup finds the taskgroup struct
* command/node_status: display CSI volume names
* nomad/state/state_store: new CSIVolumesByNodeID
* nomad/state/iterator: new SliceIterator type implements memdb.ResultIterator
* nomad/csi_endpoint: deal with a slice of volumes
* nomad/state/state_store: CSIVolumesByNodeID return a SliceIterator
* nomad/structs/csi: CSIVolumeListRequest takes a NodeID
* nomad/csi_endpoint: use the return iterator
* command/agent/csi_endpoint: parse query params for CSIVolumes.List
* api/nodes: new CSIVolumes to list volumes by node
* command/node_status: use the new list endpoint to print volumes
* nomad/state/state_store: error messages consider the operator
* command/node_status: include the Provider
Derive a provider name and version for plugins (and the volumes that
use them) from the CSI identity API `GetPluginInfo`. Expose the vendor
name as `Provider` in the API and CLI commands.
* command/csi: csi, csi_plugin, csi_volume
* helper/funcs: move ExtraKeys from parse_config to UnusedKeys
* command/agent/config_parse: use helper.UnusedKeys
* api/csi: annotate CSIVolumes with hcl fields
* command/csi_plugin: add Synopsis
* command/csi_volume_register: use hcl.Decode style parsing
* command/csi_volume_list
* command/csi_volume_status: list format, cleanup
* command/csi_plugin_list
* command/csi_plugin_status
* command/csi_volume_deregister
* command/csi_volume: add Synopsis
* api/contexts/contexts: add csi search contexts to the constants
* command/commands: register csi commands
* api/csi: fix struct tag for linter
* command/csi_plugin_list: unused struct vars
* command/csi_plugin_status: unused struct vars
* command/csi_volume_list: unused struct vars
* api/csi: add allocs to CSIPlugin
* command/csi_plugin_status: format the allocs
* api/allocations: copy Allocation.Stub in from structs
* nomad/client_rpc: add some error context with Errorf
* api/csi: collapse read & write alloc maps to a stub list
* command/csi_volume_status: cleanup allocation display
* command/csi_volume_list: use Schedulable instead of Healthy
* command/csi_volume_status: use Schedulable instead of Healthy
* command/csi_volume_list: sprintf string
* command/csi: delete csi.go, csi_plugin.go
* command/plugin: refactor csi components to sub-command plugin status
* command/plugin: remove csi
* command/plugin_status: remove csi
* command/volume: remove csi
* command/volume_status: split out csi specific
* helper/funcs: add RemoveEqualFold
* command/agent/config_parse: use helper.RemoveEqualFold
* api/csi: do ,unusedKeys right
* command/volume: refactor csi components to `nomad volume`
* command/volume_register: split out csi specific
* command/commands: use the new top level commands
* command/volume_deregister: hardwired type csi for now
* command/volume_status: csiFormatVolumes rescued from volume_list
* command/plugin_status: avoid a panic on no args
* command/volume_status: avoid a panic on no args
* command/plugin_status: predictVolumeType
* command/volume_status: predictVolumeType
* nomad/csi_endpoint_test: move CreateTestPlugin to testing
* command/plugin_status_test: use CreateTestCSIPlugin
* nomad/structs/structs: add CSIPlugins and CSIVolumes search consts
* nomad/state/state_store: add CSIPlugins and CSIVolumesByIDPrefix
* nomad/search_endpoint: add CSIPlugins and CSIVolumes
* command/plugin_status: move the header to the csi specific
* command/volume_status: move the header to the csi specific
* nomad/state/state_store: CSIPluginByID prefix
* command/status: rename the search context to just Plugins/Volumes
* command/plugin,volume_status: test return ids now
* command/status: rename the search context to just Plugins/Volumes
* command/plugin_status: support -json and -t
* command/volume_status: support -json and -t
* command/plugin_status_csi: comments
* command/*_status: clean up text
* api/csi: fix stale comments
* command/volume: make deregister sound less fearsome
* command/plugin_status: set the id length
* command/plugin_status_csi: more compact plugin health
* command/volume: better error message, comment
* structs: add ControllerRequired, volume.Name, no plug.Type
* structs: Healthy -> Schedulable
* state_store: Healthy -> Schedulable
* api: add ControllerRequired to api data types
* api: copy csi structs changes
* nomad/structs/csi: include name and external id
* api/csi: include Name and ExternalID
* nomad/structs/csi: comments for the 3 ids
* structs: CSIInfo include AllocID, CSIPlugins no Jobs
* state_store: eliminate plugin Jobs, delete an empty plugin
* nomad/structs/csi: detect empty plugins correctly
* client/allocrunner/taskrunner/plugin_supervisor_hook: option AllocID
* client/pluginmanager/csimanager/instance: allocID
* client/pluginmanager/csimanager/fingerprint: set AllocID
* client/node_updater: split controller and node plugins
* api/csi: remove Jobs
The CSI Plugin API will map plugins to allocations, which allows
plugins to be defined by jobs in many configurations. In particular,
multiple plugins can be defined in the same job, and multiple jobs can
be used to define a single plugin.
Because we now map the allocation context directly from the node, it's
no longer necessary to track the jobs associated with a plugin
directly.
* nomad/csi_endpoint_test: CreateTestPlugin & register via fingerprint
* client/dynamicplugins: lift AllocID into the struct from Options
* api/csi_test: remove Jobs test
* nomad/structs/csi: CSIPlugins has an array of allocs
* nomad/state/state_store: implement CSIPluginDenormalize
* nomad/state/state_store: CSIPluginDenormalize npe on missing alloc
* nomad/csi_endpoint_test: defer deleteNodes for clarity
* api/csi_test: disable this test awaiting mocks:
https://github.com/hashicorp/nomad/issues/7123
This changeset implements the initial registration and fingerprinting
of CSI Plugins as part of #5378. At a high level, it introduces the
following:
* A `csi_plugin` stanza as part of a Nomad task configuration, to
allow a task to expose that it is a plugin.
* A new task runner hook: `csi_plugin_supervisor`. This hook does two
things. When the `csi_plugin` stanza is detected, it will
automatically configure the plugin task to receive bidirectional
mounts to the CSI intermediary directory. At runtime, it will then
perform an initial heartbeat of the plugin and handle submitting it to
the new `dynamicplugins.Registry` for further use by the client, and
then run a lightweight heartbeat loop that will emit task events
when health changes.
* The `dynamicplugins.Registry` for handling plugins that run
as Nomad tasks, in contrast to the existing catalog that requires
`go-plugin` type plugins and to know the plugin configuration in
advance.
* The `csimanager` which fingerprints CSI plugins, in a similar way to
`drivermanager` and `devicemanager`. It currently only fingerprints
the NodeID from the plugin, and assumes that all plugins are
monolithic.
Missing features
* We do not use the live updates of the `dynamicplugin` registry in
the `csimanager` yet.
* We do not deregister the plugins from the client when they shutdown
yet, they just become indefinitely marked as unhealthy. This is
deliberate until we figure out how we should manage deploying new
versions of plugins/transitioning them.
If alloc exec fails to connect to the nomad client associated with the
alloc, fail over to using a server.
The code attempted to special case `net.Error` for failover to rule out
other permanent non-networking errors, by reusing a pattern in the
logging handling.
But this pattern does not apply here. `net/http.Http` wraps all errors
as `*url.Error` that is net.Error. The websocket doesn't, and instead
returns the raw error. If the raw error isn't a `net.Error`, like in
the case of TLS handshake errors, the api package would fail immediately
rather than failover.
When canonicalizing the ReschedulePolicy a panic was possible if
the passed job type was not valid. This change protects against
this possibility, in a verbose way to ensure the code path is
clear.
The API decodeBody function will now check the content length
before attempting to decode. If the length is zero, and the out
interface is nil then it is safe to assume the API call is not
returning any data to the user. This allows us to better handle
passing nil to API calls in a single place.
Consul provides a feature of Service Definitions where the tags
associated with a service can be modified through the Catalog API,
overriding the value(s) configured in the agent's service configuration.
To enable this feature, the flag enable_tag_override must be configured
in the service definition.
Previously, Nomad did not allow configuring this flag, and thus the default
value of false was used. Now, it is configurable.
Because Nomad itself acts as a state machine around the the service definitions
of the tasks it manages, it's worth describing what happens when this feature
is enabled and why.
Consider the basic case where there is no Nomad, and your service is provided
to consul as a boring JSON file. The ultimate source of truth for the definition
of that service is the file, and is stored in the agent. Later, Consul performs
"anti-entropy" which synchronizes the Catalog (stored only the leaders). Then
with enable_tag_override=true, the tags field is available for "external"
modification through the Catalog API (rather than directly configuring the
service definition file, or using the Agent API). The important observation
is that if the service definition ever changes (i.e. the file is changed &
config reloaded OR the Agent API is used to modify the service), those
"external" tag values are thrown away, and the new service definition is
once again the source of truth.
In the Nomad case, Nomad itself is the source of truth over the Agent in
the same way the JSON file was the source of truth in the example above.
That means any time Nomad sets a new service definition, any externally
configured tags are going to be replaced. When does this happen? Only on
major lifecycle events, for example when a task is modified because of an
updated job spec from the 'nomad job run <existing>' command. Otherwise,
Nomad's periodic re-sync's with Consul will now no longer try to restore
the externally modified tag values (as long as enable_tag_override=true).
Fixes#2057
This change provides an initial pass at setting up the configuration necessary to
enable use of Connect with Consul ACLs. Operators will be able to pass in a Consul
Token through `-consul-token` or `$CONSUL_TOKEN` in the `job run` and `job revert`
commands (similar to Vault tokens).
These values are not actually used yet in this changeset.
copy struct values
ensure groupserviceHook implements RunnerPreKillhook
run deregister first
test that shutdown times are delayed
move magic number into variable
The existing version constraint uses logic optimized for package
managers, not schedulers, when checking prereleases:
- 1.3.0-beta1 will *not* satisfy ">= 0.6.1"
- 1.7.0-rc1 will *not* satisfy ">= 1.6.0-beta1"
This is due to package managers wishing to favor final releases over
prereleases.
In a scheduler versions more often represent the earliest release all
required features/APIs are available in a system. Whether the constraint
or the version being evaluated are prereleases has no impact on
ordering.
This commit adds a new constraint - `semver` - which will use Semver
v2.0 ordering when evaluating constraints. Given the above examples:
- 1.3.0-beta1 satisfies ">= 0.6.1" using `semver`
- 1.7.0-rc1 satisfies ">= 1.6.0-beta1" using `semver`
Since existing jobspecs may rely on the old behavior, a new constraint
was added and the implicit Consul Connect and Vault constraints were
updated to use it.
If a websocket connection errors we currently return the error with a
copy of the response body. The response body from the websocket can
often times be completely illegible so remove it from the error string.
make alloc id empty for more reliable failure
un-gzip if content encoding header present
Jobs can be created with user-provided IDs containing any character
except spaces. The jobId needs to be escaped when used in a request
path, otherwise jobs created with names such as "why?" can't be managed
after they are created.
This commit introduces support for configuring mount propagation when
mounting volumes with the `volume_mount` stanza on Linux targets.
Similar to Kubernetes, we expose 3 options for configuring mount
propagation:
- private, which is equivalent to `rprivate` on Linux, which does not allow the
container to see any new nested mounts after the chroot was created.
- host-to-task, which is equivalent to `rslave` on Linux, which allows new mounts
that have been created _outside of the container_ to be visible
inside the container after the chroot is created.
- bidirectional, which is equivalent to `rshared` on Linux, which allows both
the container to see new mounts created on the host, but
importantly _allows the container to create mounts that are
visible in other containers an don the host_
private and host-to-task are safe, but bidirectional mounts can be
dangerous, as if the code inside a container creates a mount, and does
not clean it up before tearing down the container, it can cause bad
things to happen inside the kernel.
To add a layer of safety here, we require that the user has ReadWrite
permissions on the volume before allowing bidirectional mounts, as a
defense in depth / validation case, although creating mounts should also require
a priviliged execution environment inside the container.
This fixes a bug in the CLI handling of node lookup failures when
querying allocation and FS endpoints.
Allocation and FS endpoint are handled by the client; one can query the
relevant client directly, or query a server to have it forwarded
transparently to relevant client. Querying the client directly is
benefecial to avoid loading servers with IO.
As an optimization, the CLI attempts to query the client directly, but
then falls back to using server forwarding path if it encounters network
or connection errors (e.g. clients are locked down or in a separate
inaccessible network).
Here, we fix a bug where if the CLI fails to find to lookup the client
details because it lacks ACL capability or other unexpected reasons, the
CLI will not go through fallback path.
Without a `LocalServicePort`, Connect services will try to use the
mapped port even when delivering traffic locally. A user can override
this behavior by pinning the port value in the `service` stanza but
this prevents us from using the Consul service name to reach the
service.
This commits configures the Consul proxy with its `LocalServicePort`
and `LocalServiceAddress` fields.
Currently, using a Volume in a job uses the following configuration:
```
volume "alias-name" {
type = "volume-type"
read_only = true
config {
source = "host_volume_name"
}
}
```
This commit migrates to the following:
```
volume "alias-name" {
type = "volume-type"
source = "host_volume_name"
read_only = true
}
```
The original design was based due to being uncertain about the future of storage
plugins, and to allow maxium flexibility.
However, this causes a few issues, namely:
- We frequently need to parse this configuration during submission,
scheduling, and mounting
- It complicates the configuration from and end users perspective
- It complicates the ability to do validation
As we understand the problem space of CSI a little more, it has become
clear that we won't need the `source` to be in config, as it will be
used in the majority of cases:
- Host Volumes: Always need a source
- Preallocated CSI Volumes: Always needs a source from a volume or claim name
- Dynamic Persistent CSI Volumes*: Always needs a source to attach the volumes
to for managing upgrades and to avoid dangling.
- Dynamic Ephemeral CSI Volumes*: Less thought out, but `source` will probably point
to the plugin name, and a `config` block will
allow you to pass meta to the plugin. Or will
point to a pre-configured ephemeral config.
*If implemented
The new design simplifies this by merging the source into the volume
stanza to solve the above issues with usability, performance, and error
handling.
* adds meta object to service in job spec, sends it to consul
* adds tests for service meta
* fix tests
* adds docs
* better hashing for service meta, use helper for copying meta when registering service
* tried to be DRY, but looks like it would be more work to use the
helper function
* jobspec: breakup parse.go into smaller files
* add sidecar_task parsing to jobspec and api
* jobspec: combine service parsing logic for task and group service stanzas
* api: use slice of ConsulUpstream values instead of pointers
- updated region in job metadata that gets persisted to nomad datastore
- fixed many unrelated unit tests that used an invalid region value
(they previously passed because hcl wasn't getting picked up and
the job would default to global region)
`*Config.ConfigureTLS()` is invoked internally by `NewClient` and API
consumers should not invoke directly.
Now that http client is created in `api.NewClient`,
`*Config.ConfigureTLS` makes no sense. API consumers that call it
explicitly can remove the invocation and preserve the behavior.
Allow clients to configure httpClient, e.g. set a pooled/keep-alive
client.
When caller configures HttpClient explicitly, we aim to use as-is; e.g.
we assume it's configured with TLS already. Expose `ConfigureTLS` to
aid api consumers with configuring their http client.
Also, removes `SetTimeout` call that I believe is internal only and has
odd side-effects when called on already created config. Also deprecates
`config.ConfigureTLS` in preference to the new `ConfigureTLS`.
Adds nomad exec support in our API, by hitting the websocket endpoint.
We introduce API structs that correspond to the drivers streaming exec structs.
For creating the websocket connection, we reuse the transport setting from api
http client.
This command will be used to send a signal to either a single task within an
allocation, or all of the tasks if <task-name> is omitted. If the sent signal
terminates the allocation, it will be treated as if the allocation has crashed,
rather than as if it was operator-terminated.
Signal validation is currently handled by the driver itself and nomad
does not attempt to restrict or validate them.
This adds a `nomad alloc stop` command that can be used to stop and
force migrate an allocation to a different node.
This is built on top of the AllocUpdateDesiredTransitionRequest and
explicitly limits the scope of access to that transition to expose it
under the alloc-lifecycle ACL.
The API returns the follow up eval that can be used as part of
monitoring in the CLI or parsed and used in an external tool.
This adds a `nomad alloc restart` command and api that allows a job operator
with the alloc-lifecycle acl to perform an in-place restart of a Nomad
allocation, or a given subtask.
Currently when operators need to log onto a machine where an alloc
is running they will need to perform both an alloc/job status
call and then a call to discover the node name from the node list.
This updates both the job status and alloc status output to include
the node name within the information to make operator use easier.
Closes#2359
Cloess #1180
* Divest api/ package of deps elsewhere in the nomad repo.
This will allow making api/ a module without then pulling in the
external repo, leading to a package name conflict.
This required some migration of tests to an apitests/ folder (can be
moved anywhere as it has no deps on it). It also required some
duplication of code, notably some test helpers from api/ -> apitests/
and part (but not all) of testutil/ -> api/testutil/.
Once there's more separation and an e.g. sdk/ folder those can be
removed in favor of a dep on the sdk/ folder, provided the sdk/ folder
doesn't depend on api/ or /.
* Also remove consul dep from api/ package
* Fix stupid linters
* Some restructuring
Add some tests to ensure that api/structs values are in sync.
Given that vendoring libraries prune tests by default, test dependencies
aren't leaked to clients of the package - so it should be safe to add
such dependency without affecting api clients.
Given that the values will rarely change, specially considering that any
changes would be backward incompatible change. As such, it's simpler to
keep syncing manually in the rare occasion and avoid the syncing code
overhead.
Embed pointer conversion functions in the API package to avoid
unnecessary package dependency. `helper` package imports more
dependencies relevant for internal use (e.g. `hcl`).
nomad/structs is an internal package and imports many libraries (e.g.
raft, codec) that are not relevant to api clients, and may cause
unnecessary dependency pain (e.g. `github.com/ugorji/go/codec`
version is very old now).
Here, we add a code generator that imports the relevant constants from
`nomad/structs`.
I considered using this approach for other structs, but didn't find a
quick viable way to reduce duplication. `nomad/structs` use values as
struct fields (e.g. `string`), while `api` uses value pointer (e.g.
`*string`) instead. Also, sometimes, `api` structs contain deprecated
fields or additional documentation, so simple copy-paste doesn't work.
For these reasons, I opt to keep the status quo.
Track current memory usage, `memory.usage_in_bytes`, in addition to
`memory.max_memory_usage_in_bytes` and friends. This number is closer
what Docker reports.
Related to https://github.com/hashicorp/nomad/issues/5165 .
