When agents start, they create a shared Consul client that is then wrapped as
various interfaces for testability, and used in constructing the Nomad client
and server. The interfaces that support workload services (rather than the Nomad
agent itself) need to support multiple Consul clusters for Nomad
Enterprise. Update these interfaces to be factory functions that return the
Consul client for a given cluster name. Update the `ServiceClient` to split
workload updates between clusters by creating a wrapper around all the clients
that delegates to the cluster-specific `ServiceClient`.
Ref: https://github.com/hashicorp/team-nomad/issues/404
* 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>`.
This commit splits identity_hook between the allocrunner and taskrunner. The
allocrunner-level part of the hook signs each task identity, and the
taskrunner-level part picks it up and stores secrets for each task.
The code revamps the WIDMgr, which is now split into 2 interfaces:
IdentityManager which manages renewals of signatures and handles sending
updates to subscribers via Watch method, and IdentitySigner which only does the
signing.
This work is necessary for having a unified Consul login workflow that comes
with the new Consul integration. A new, allocrunner-level consul_hook will now
be the only hook doing Consul authentication.
Nomad Enterprise will support configuring multiple Vault clients. Instead of
having a single Vault client field in the Nomad client, we'll have a function
that callers can parameterize by the Vault cluster name that returns the
correctly configured Vault API client wrapper.
* 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
Allows for multiple `identity{}` blocks for tasks along with user-specified audiences. This is a building block to allow workload identities to be used with Consul, Vault and 3rd party JWT based auth methods.
Expiration is still unimplemented and is necessary for JWTs to be used securely, so that's up next.
---------
Co-authored-by: Tim Gross <tgross@hashicorp.com>
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.
* Update ioutil deprecated library references to os and io respectively
* Deal with the errors produced.
Add error handling to filEntry info
Add error handling to info
* artifact: protect against unbounded artifact decompression
Starting with 1.5.0, set defaut values for artifact decompression limits.
artifact.decompression_size_limit (default "100GB") - the maximum amount of
data that will be decompressed before triggering an error and cancelling
the operation
artifact.decompression_file_count_limit (default 4096) - the maximum number
of files that will be decompressed before triggering an error and
cancelling the operation.
* artifact: assert limits cannot be nil in validation
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>
* artifact: enable inheriting environment variables from client
This PR adds client configuration for specifying environment variables that
should be inherited by the artifact sandbox process from the Nomad Client agent.
Most users should not need to set these values but the configuration is provided
to ensure backwards compatability. Configuration of go-getter should ideally be
done through the artifact block in a jobspec task.
e.g.
```hcl
client {
artifact {
set_environment_variables = "TMPDIR,GIT_SSH_OPTS"
}
}
```
Closes#15498
* website: update set_environment_variables text to mention PATH
This PR adds the client config option for turning off filesystem isolation,
applicable on Linux systems where filesystem isolation is possible and
enabled by default.
```hcl
client{
artifact {
disable_filesystem_isolation = <bool:false>
}
}
```
Closes#15496
* client: sandbox go-getter subprocess with landlock
This PR re-implements the getter package for artifact downloads as a subprocess.
Key changes include
On all platforms, run getter as a child process of the Nomad agent.
On Linux platforms running as root, run the child process as the nobody user.
On supporting Linux kernels, uses landlock for filesystem isolation (via go-landlock).
On all platforms, restrict environment variables of the child process to a static set.
notably TMP/TEMP now points within the allocation's task directory
kernel.landlock attribute is fingerprinted (version number or unavailable)
These changes make Nomad client more resilient against a faulty go-getter implementation that may panic, and more secure against bad actors attempting to use artifact downloads as a privilege escalation vector.
Adds new e2e/artifact suite for ensuring artifact downloading works.
TODO: Windows git test (need to modify the image, etc... followup PR)
* landlock: fixup items from cr
* cr: fixup tests and go.mod file
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!"
This PR fixes a bug where client configuration max_kill_timeout was
not being enforced. The feature was introduced in 9f44780 but seems
to have been removed during the major drivers refactoring.
We can make sure the value is enforced by pluming it through the DriverHandler,
which now uses the lesser of the task.killTimeout or client.maxKillTimeout.
Also updates Event.SetKillTimeout to require both the task.killTimeout and
client.maxKillTimeout so that we don't make the mistake of using the wrong
value - as it was being given only the task.killTimeout before.
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.
This PR is 2 fixes for the flaky TestTaskRunner_TaskEnv_Chroot test.
And also the TestTaskRunner_Download_ChrootExec test.
- Use TinyChroot to stop copying gigabytes of junk, which causes GHA
to fail to create the environment in time.
- Pre-create cgroups on V2 systems. Normally the cgroup directory is
managed by the cpuset manager, but that is not active in taskrunner tests,
so create it by hand in the test framework.
This change modifies the template task runner to utilise the
new consul-template which includes Nomad service lookup template
funcs.
In order to provide security and auth to consul-template, we use
a custom HTTP dialer which is passed to consul-template when
setting up the runner. This method follows Vault implementation.
Co-authored-by: Michael Schurter <mschurter@hashicorp.com>
Resolves#12095 by WONTFIXing it.
This approach disables `writeToFile` as it allows arbitrary host
filesystem writes and is only a small quality of life improvement over
multiple `template` stanzas.
This approach has the significant downside of leaving people who have
altered their `template.function_denylist` *still vulnerable!* I added
an upgrade note, but we should have implemented the denylist as a
`map[string]bool` so that new funcs could be denied without overriding
custom configurations.
This PR also includes a bug fix that broke enabling all consul-template
funcs. We repeatedly failed to differentiate between a nil (unset)
denylist and an empty (allow all) one.
This PR introduces support for using Nomad on systems with cgroups v2 [1]
enabled as the cgroups controller mounted on /sys/fs/cgroups. Newer Linux
distros like Ubuntu 21.10 are shipping with cgroups v2 only, causing problems
for Nomad users.
Nomad mostly "just works" with cgroups v2 due to the indirection via libcontainer,
but not so for managing cpuset cgroups. Before, Nomad has been making use of
a feature in v1 where a PID could be a member of more than one cgroup. In v2
this is no longer possible, and so the logic around computing cpuset values
must be modified. When Nomad detects v2, it manages cpuset values in-process,
rather than making use of cgroup heirarchy inheritence via shared/reserved
parents.
Nomad will only activate the v2 logic when it detects cgroups2 is mounted at
/sys/fs/cgroups. This means on systems running in hybrid mode with cgroups2
mounted at /sys/fs/cgroups/unified (as is typical) Nomad will continue to
use the v1 logic, and should operate as before. Systems that do not support
cgroups v2 are also not affected.
When v2 is activated, Nomad will create a parent called nomad.slice (unless
otherwise configured in Client conifg), and create cgroups for tasks using
naming convention <allocID>-<task>.scope. These follow the naming convention
set by systemd and also used by Docker when cgroups v2 is detected.
Client nodes now export a new fingerprint attribute, unique.cgroups.version
which will be set to 'v1' or 'v2' to indicate the cgroups regime in use by
Nomad.
The new cpuset management strategy fixes#11705, where docker tasks that
spawned processes on startup would "leak". In cgroups v2, the PIDs are
started in the cgroup they will always live in, and thus the cause of
the leak is eliminated.
[1] https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.htmlCloses#11289Fixes#11705#11773#11933
This PR exposes the following existing`consul-template` configuration options to Nomad jobspec authors in the `{job.group.task.template}` stanza.
- `wait`
It also exposes the following`consul-template` configuration to Nomad operators in the `{client.template}` stanza.
- `max_stale`
- `block_query_wait`
- `consul_retry`
- `vault_retry`
- `wait`
Finally, it adds the following new Nomad-specific configuration to the `{client.template}` stanza that allows Operators to set bounds on what `jobspec` authors configure.
- `wait_bounds`
Co-authored-by: Tim Gross <tgross@hashicorp.com>
Co-authored-by: Michael Schurter <mschurter@hashicorp.com>
