When we renew Vault tokens, we use the lease duration to determine how often to
renew. But we also set an `increment` value which is never updated from the
initial 30s. For periodic tokens this is not a problem because the `increment`
field is ignored on renewal. But for non-periodic tokens this prevents the token
TTL from being properly incremented. This behavior has been in place since the
initial Vault client implementation in #1606 but before the switch to workload
identity most (all?) tokens being created were periodic tokens so this was never
detected.
Fix this bug by updating the request's `increment` field to the lease duration
on each renewal.
Also switch out a `time.After` call in backoff of the derive token caller with a
safe timer so that we don't have to spawn a new goroutine per loop, and have
tighter control over when that's GC'd.
Ref: https://github.com/hashicorp/nomad/pull/1606
Ref: https://github.com/hashicorp/nomad/issues/25812
Some of our allocrunner hooks require a task environment for interpolating values based on the node or allocation. But several of the hooks accept an already-built environment or builder and then keep that in memory. Both of these retain a copy of all the node attributes and allocation metadata, which balloons memory usage until the allocation is GC'd.
While we'd like to look into ways to avoid keeping the allocrunner around entirely (see #25372), for now we can significantly reduce memory usage by creating the task environment on-demand when calling allocrunner methods, rather than persisting it in the allocrunner hooks.
In doing so, we uncover two other bugs:
* The WID manager, the group service hook, and the checks hook have to interpolate services for specific tasks. They mutated a taskenv builder to do so, but each time they mutate the builder, they write to the same environment map. When a group has multiple tasks, it's possible for one task to set an environment variable that would then be interpolated in the service definition for another task if that task did not have that environment variable. Only the service definition interpolation is impacted. This does not leak env vars across running tasks, as each taskrunner has its own builder.
To fix this, we move the `UpdateTask` method off the builder and onto the taskenv as the `WithTask` method. This makes a shallow copy of the taskenv with a deep clone of the environment map used for interpolation, and then overwrites the environment from the task.
* The checks hook interpolates Nomad native service checks only on `Prerun` and not on `Update`. This could cause unexpected deregistration and registration of checks during in-place updates. To fix this, we make sure we interpolate in the `Update` method.
I also bumped into an incorrectly implemented interface in the CSI hook. I've pulled that and some better guardrails out to https://github.com/hashicorp/nomad/pull/25472.
Fixes: https://github.com/hashicorp/nomad/issues/25269
Fixes: https://hashicorp.atlassian.net/browse/NET-12310
Ref: https://github.com/hashicorp/nomad/issues/25372
The legacy workflow for Vault whereby servers were configured
using a token to provide authentication to the Vault API has now
been removed. This change also removes the workflow where servers
were responsible for deriving Vault tokens for Nomad clients.
The deprecated Vault config options used byi the Nomad agent have
all been removed except for "token" which is still in use by the
Vault Transit keyring implementation.
Job specification authors can no longer use the "vault.policies"
parameter and should instead use "vault.role" when not using the
default workload identity.
---------
Co-authored-by: Tim Gross <tgross@hashicorp.com>
Co-authored-by: Aimee Ukasick <aimee.ukasick@hashicorp.com>
Services can have some of their string fields interpolated. The new Workload
Identity flow doesn't interpolate the services before requesting signed
identities or using those identities to get Consul tokens.
Add support for interpolation to the WID manager and the Consul tokens hook by
providing both with a taskenv builder. Add an "interpolate workload" field to
the WI handle to allow passing the original workload name to the server so the
server can find the correct service to sign.
This changeset also makes two related test improvements:
* Remove the mock WID manager, which was only used in the Consul hook tests and
isn't necessary so long as we provide the real WID manager with the mock
signer and never call `Run` on it. It wasn't feasible to exercise the correct
behavior without this refactor, as the mocks were bypassing the new code.
* Fixed swapped expect-vs-actual assertions on the `consul_hook` tests.
Fixes: https://github.com/hashicorp/nomad/issues/20025
Some users with batch workloads or short-lived prestart tasks want to derive a
Vaul token, use it, and then allow it to expire without requiring a constant
refresh. Add the `vault.allow_token_expiration` field, which works only with the
Workload Identity workflow and not the legacy workflow.
When set to true, this disables the client's renewal loop in the
`vault_hook`. When Vault revokes the token lease, the token will no longer be
valid. The client will also now automatically detect if the Vault auth
configuration does not allow renewals and will disable the renewal loop
automatically.
Note this should only be used when a secret is requested from Vault once at the
start of a task or in a short-lived prestart task. Long-running tasks should
never set `allow_token_expiration=true` if they obtain Vault secrets via
`template` blocks, as the Vault token will expire and the template runner will
continue to make failing requests to Vault until the `vault_retry` attempts are
exhausted.
Fixes: https://github.com/hashicorp/nomad/issues/8690
