This change implements the client -> server workflow for Nomad
node introduction. A Nomad node can optionally be started with an
introduction token, which is a signed JWT containing claims for
the node registration. The server handles this according to the
enforcement configuration.
The introduction token can be provided by env var, cli flag, or
by placing it within a default filesystem location. The latter
option does not override the CLI or env var.
The region claims has been removed from the initial claims set of
the intro identity. This boundary is guarded by mTLS and aligns
with the node identity.
* Add MonitorExport command and handlers
* Implement autocomplete
* Require nomad in serviceName
* Fix race in StreamReader.Read
* Add and use framer.Flush() to coordinate function exit
* Add LogFile to client/Server config and read NomadLogPath in rpcHandler instead of HTTPServer
* Parameterize StreamFixed stream size
When a node is garbage collected, any dynamic host volumes on the node are
orphaned in the state store. We generally don't want to automatically collect
these volumes and risk data loss, and have provided a CLI flag to `-force`
remove them in #25902. But for clusters running on ephemeral cloud
instances (ex. AWS EC2 in an autoscaling group), deleting host volumes may add
excessive friction. Add a configuration knob to the client configuration to
remove host volumes from the state store on node GC.
Ref: https://github.com/hashicorp/nomad/pull/25902
Ref: https://github.com/hashicorp/nomad/issues/25762
Ref: https://hashicorp.atlassian.net/browse/NMD-705
* Set MaxAllocations in client config
Add NodeAllocationTracker struct to Node struct
Evaluate MaxAllocations in AllocsFit function
Set up cli config parsing
Integrate maxAllocs into AllocatedResources view
Co-authored-by: Tim Gross <tgross@hashicorp.com>
---------
Co-authored-by: Tim Gross <tgross@hashicorp.com>
Before the fixes in #20165, the wait feature was disabled by
default. After these changes, it's always enabled, which - at
least on some platforms - leads to a significant increase in
load (5-7x).
This patch allows disabling the wait feature in the client
stanza of the configuration file by setting min and max to 0:
wait {
min = "0"
max = "0"
}
Per-template wait blocks in the task description still work like
one would expect.
In #20165 we fixed a bug where a partially configured `client.template` retry
block would set any unset fields to nil instead of their default values. But
this patch introduced a regression in the default values, so we were now
defaulting to unlimited retries if the retry block was unset. Restore the
correct behavior and add better test coverage at both the config parsing and
template configuration code.
Ref: https://github.com/hashicorp/nomad/pull/20165
Ref: https://github.com/hashicorp/nomad/issues/23305#issuecomment-2643731565
The Nomad client can now optionally emit telemetry data from the
prerun and prestart hooks. This allows operators to monitor and
alert on failures and time taken to complete.
The new datapoints are:
- nomad.client.alloc_hook.prerun.success (counter)
- nomad.client.alloc_hook.prerun.failed (counter)
- nomad.client.alloc_hook.prerun.elapsed (sample)
- nomad.client.task_hook.prestart.success (counter)
- nomad.client.task_hook.prestart.failed (counter)
- nomad.client.task_hook.prestart.elapsed (sample)
The hook execution time is useful to Nomad engineering and will
help optimize code where possible and understand job specification
impacts on hook performance.
Currently only the PreRun and PreStart hooks have telemetry
enabled, so we limit the number of new metrics being produced.
This PR adds Consul Template's executeTemplate function to the denylist by
default, in order to prevent accidental or malicious infinitely recursive
execution.
---------
Co-authored-by: Tim Gross <tgross@hashicorp.com>
Nomad creates Consul ACL tokens and service registrations to support Consul
service mesh workloads, before bootstrapping the Envoy proxy. Nomad always talks
to the local Consul agent and never directly to the Consul servers. But the
local Consul agent talks to the Consul servers in stale consistency mode to
reduce load on the servers. This can result in the Nomad client making the Envoy
bootstrap request with a tokens or services that have not yet replicated to the
follower that the local client is connected to. This request gets a 404 on the
ACL token and that negative entry gets cached, preventing any retries from
succeeding.
To workaround this, we'll use a method described by our friends over on
`consul-k8s` where after creating the objects in Consul we try to read them from
the local agent in stale consistency mode (which prevents a failed read from
being cached). This cannot completely eliminate this source of error because
it's possible that Consul cluster replication is unhealthy at the time we need
it, but this should make Envoy bootstrap significantly more robust.
This changset adds preflight checks for the objects we create in Consul:
* We add a preflight check for ACL tokens after we login via via Workload
Identity and in the function we use to derive tokens in the legacy
workflow. We do this check early because we also want to use this token for
registering group services in the allocrunner hooks.
* We add a preflight check for services right before we bootstrap Envoy in the
taskrunner hook, so that we have time for our service client to batch updates
to the local Consul agent in addition to the local agent sync.
We've added the timeouts to be configurable via node metadata rather than the
usual static configuration because for most cases, users should not need to
touch or even know these values are configurable; the configuration is mostly
available for testing.
Fixes: https://github.com/hashicorp/nomad/issues/9307
Fixes: https://github.com/hashicorp/nomad/issues/10451
Fixes: https://github.com/hashicorp/nomad/issues/20516
Ref: https://github.com/hashicorp/consul-k8s/pull/887
Ref: https://hashicorp.atlassian.net/browse/NET-10051
Ref: https://hashicorp.atlassian.net/browse/NET-9273
Follow-up: https://hashicorp.atlassian.net/browse/NET-10138
When loading the client configuration, the user-specified `client.template`
block was not properly merged with the default values. As a result, if the user
set any `client.template` field, all the other field defaulted to their zero
values instead of the documented defaults.
This changeset:
* Adds the missing `Merge` method for the client template config and ensures
it's called.
* Makes a single source of truth for the default template configuration,
instead of two different constructors.
* Extends the tests to cover the merge of a partial block better.
Fixes: https://github.com/hashicorp/nomad/issues/20164
* exec2: add client support for unveil filesystem isolation mode
This PR adds support for a new filesystem isolation mode, "Unveil". The
mode introduces a "alloc_mounts" directory where tasks have user-owned
directory structure which are bind mounts into the real alloc directory
structure. This enables a task driver to use landlock (and maybe the
real unveil on openbsd one day) to isolate a task to the task owned
directory structure, providing sandboxing.
* actually create alloc-mounts-dir directory
* fix doc strings about alloc mount dir paths
* exec: add a client.users configuration block
For now just add min/max dynamic user values; soon we can also absorb
the "user.denylist" and "user.checked_drivers" options from the
deprecated client.options map.
* give the no-op pool implementation a better name
* use explicit error types to make referencing them cleaner in tests
* use import alias to not shadow package name
Remove the now-unused original configuration blocks for Consul and Vault from
the client. When the client needs to refer to a Consul or Vault block it will
always be for a specific cluster for the task/service. Add a helper for
accessing the default clusters (for the client's own use).
This is two of three changesets for this work. The remainder will implement the
same changes in the `command/agent` package.
As part of this work I discovered and fixed two bugs:
* The gRPC proxy socket that we create for Envoy is only ever created using the
default Consul cluster's configuration. This will prevent Connect from being
used with the non-default cluster.
* The Consul configuration we use for templates always comes from the default
Consul cluster's configuration, but will use the correct Consul token for the
non-default cluster. This will prevent templates from being used with the
non-default cluster.
Ref: https://github.com/hashicorp/nomad/issues/18947
Ref: https://github.com/hashicorp/nomad/pull/18991
Fixes: https://github.com/hashicorp/nomad/issues/18984
Fixes: https://github.com/hashicorp/nomad/issues/18983
* vault: update identity name to start with `vault_`
In the original proposal, workload identities used to derive Vault
tokens were expected to be called just `vault`. But in order to support
multiple Vault clusters it is necessary to associate identities with
specific Vault cluster configuration.
This commit implements a new proposal to have Vault identities named as
`vault_<cluster>`.
* drivers: plumb hardware topology via grpc into drivers
This PR swaps out the temporary use of detecting system hardware manually
in each driver for using the Client's detected topology by plumbing the
data over gRPC. This ensures that Client configuration is taken to account
consistently in all references to system topology.
* cr: use enum instead of bool for core grade
* cr: fix test slit tables to be possible
* client: refactor cpuset partitioning
This PR updates the way Nomad client manages the split between tasks
that make use of resources.cpus vs. resources.cores.
Previously, each task was explicitly assigned which CPU cores they were
able to run on. Every time a task was started or destroyed, all other
tasks' cpusets would need to be updated. This was inefficient and would
crush the Linux kernel when a client would try to run ~400 or so tasks.
Now, we make use of cgroup heirarchy and cpuset inheritence to efficiently
manage cpusets.
* cr: tweaks for feedback
Add the plumbing we need to accept multiple Consul clusters in Nomad agent
configuration, to support upcoming Nomad Enterprise features. The `consul` blocks
are differentiated by a new `name` field, and if the `name` is omitted it
becomes the "default" Consul configuration. All blocks with the same name are
merged together, as with the existing behavior.
As with the `vault` block, we're still using HCL1 for parsing configuration and
the `Decode` method doesn't parse multiple blocks differentiated only by a field
name without a label. So we've had to add an extra parsing pass, similar to what
we've done for HCL1 jobspecs. This also revealed a subtle bug in the `vault`
block handling of extra keys when there are multiple `vault` blocks, which I've
fixed here.
For now, all existing consumers will use the "default" Consul configuration, so
there's no user-facing behavior change in this changeset other than the contents
of the agent self API.
Ref: https://github.com/hashicorp/team-nomad/issues/404
Add the plumbing we need to accept multiple Vault clusters in Nomad agent
configuration, to support upcoming Nomad Enterprise features. The `vault` blocks
are differentiated by a new `name` field, and if the `name` is omitted it
becomes the "default" Vault configuration. All blocks with the same name are
merged together, as with the existing behavior.
Unfortunately we're still using HCL1 for parsing configuration and the `Decode`
method doesn't parse multiple blocks differentiated only by a field name without
a label. So we've had to add an extra parsing pass, similar to what we've done
for HCL1 jobspecs.
For now, all existing consumers will use the "default" Vault configuration, so
there's no user-facing behavior change in this changeset other than the contents
of the agent self API.
Ref: https://github.com/hashicorp/team-nomad/issues/404
Tools like `nomad-nodesim` are unable to implement a minimal implementation of
an allocrunner so that we can test the client communication without having to
lug around the entire allocrunner/taskrunner code base. The allocrunner was
implemented with an interface specifically for this purpose, but there were
circular imports that made it challenging to use in practice.
Move the AllocRunner interface into an inner package and provide a factory
function type. Provide a minimal test that exercises the new function so that
consumers have some idea of what the minimum implementation required is.
to avoid leaking task resources (e.g. containers,
iptables) if allocRunner prerun fails during
restore on client restart.
now if prerun fails, TaskRunner.MarkFailedKill()
will only emit an event, mark the task as failed,
and cancel the tr's killCtx, so then ar.runTasks()
-> tr.Run() can take care of the actual cleanup.
removed from (formerly) tr.MarkFailedDead(),
now handled by tr.Run():
* set task state as dead
* save task runner local state
* task stop hooks
also done in tr.Run() now that it's not skipped:
* handleKill() to kill tasks while respecting
their shutdown delay, and retrying as needed
* also includes task preKill hooks
* clearDriverHandle() to destroy the task
and associated resources
* task exited hooks
Adds a new configuration to clients to optionally allow them to drain their
workloads on shutdown. The client sends the `Node.UpdateDrain` RPC targeting
itself and then monitors the drain state as seen by the server until the drain
is complete or the deadline expires. If it loses connection with the server, it
will monitor local client status instead to ensure allocations are stopped
before exiting.
This change introduces the Task API: a portable way for tasks to access Nomad's HTTP API. This particular implementation uses a Unix Domain Socket and, unlike the agent's HTTP API, always requires authentication even if ACLs are disabled.
This PR contains the core feature and tests but followup work is required for the following TODO items:
- Docs - might do in a followup since dynamic node metadata / task api / workload id all need to interlink
- Unit tests for auth middleware
- Caching for auth middleware
- Rate limiting on negative lookups for auth middleware
---------
Co-authored-by: Seth Hoenig <shoenig@duck.com>
* Add `bridge_network_hairpin_mode` client config setting
* Add node attribute: `nomad.bridge.hairpin_mode`
* Changed format string to use `%q` to escape user provided data
* Add test to validate template JSON for developer safety
Co-authored-by: Daniel Bennett <dbennett@hashicorp.com>
The client ACL cache was not accounting for tokens which included
ACL role links. This change modifies the behaviour to resolve role
links to policies. It will also now store ACL roles within the
cache for quick lookup. The cache TTL is configurable in the same
manner as policies or tokens.
Another small fix is included that takes into account the ACL
token expiry time. This was not included, which meant tokens with
expiry could be used past the expiry time, until they were GC'd.
* cleanup: refactor MapStringStringSliceValueSet to be cleaner
* cleanup: replace SliceStringToSet with actual set
* cleanup: replace SliceStringSubset with real set
* cleanup: replace SliceStringContains with slices.Contains
* cleanup: remove unused function SliceStringHasPrefix
* cleanup: fixup StringHasPrefixInSlice doc string
* cleanup: refactor SliceSetDisjoint to use real set
* cleanup: replace CompareSliceSetString with SliceSetEq
* cleanup: replace CompareMapStringString with maps.Equal
* cleanup: replace CopyMapStringString with CopyMap
* cleanup: replace CopyMapStringInterface with CopyMap
* cleanup: fixup more CopyMapStringString and CopyMapStringInt
* cleanup: replace CopySliceString with slices.Clone
* cleanup: remove unused CopySliceInt
* cleanup: refactor CopyMapStringSliceString to be generic as CopyMapOfSlice
* cleanup: replace CopyMap with maps.Clone
* cleanup: run go mod tidy
Before this change, Client had 2 copies of the config object: config and configCopy. There was no guidance around which to use where (other than configCopy's comment to pass it to alloc runners), both are shared among goroutines and mutated in data racy ways. At least at one point I think the idea was to have `config` be mutable and then grab a lock to overwrite `configCopy`'s pointer atomically. This would have allowed alloc runners to read their config copies in data race safe ways, but this isn't how the current implementation worked.
This change takes the following approach to safely handling configs in the client:
1. `Client.config` is the only copy of the config and all access must go through the `Client.configLock` mutex
2. Since the mutex *only protects the config pointer itself and not fields inside the Config struct:* all config mutation must be done on a *copy* of the config, and then Client's config pointer is overwritten while the mutex is acquired. Alloc runners and other goroutines with the old config pointer will not see config updates.
3. Deep copying is implemented on the Config struct to satisfy the previous approach. The TLS Keyloader is an exception because it has its own internal locking to support mutating in place. An unfortunate complication but one I couldn't find a way to untangle in a timely fashion.
4. To facilitate deep copying I made an *internally backward incompatible API change:* our `helper/funcs` used to turn containers (slices and maps) with 0 elements into nils. This probably saves a few memory allocations but makes it very easy to cause panics. Since my new config handling approach uses more copying, it became very difficult to ensure all code that used containers on configs could handle nils properly. Since this code has caused panics in the past, I fixed it: nil containers are copied as nil, but 0-element containers properly return a new 0-element container. No more "downgrading to nil!"
Fix numerous go-getter security issues:
- Add timeouts to http, git, and hg operations to prevent DoS
- Add size limit to http to prevent resource exhaustion
- Disable following symlinks in both artifacts and `job run`
- Stop performing initial HEAD request to avoid file corruption on
retries and DoS opportunities.
**Approach**
Since Nomad has no ability to differentiate a DoS-via-large-artifact vs
a legitimate workload, all of the new limits are configurable at the
client agent level.
The max size of HTTP downloads is also exposed as a node attribute so
that if some workloads have large artifacts they can specify a high
limit in their jobspecs.
In the future all of this plumbing could be extended to enable/disable
specific getters or artifact downloading entirely on a per-node basis.
