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.
Pass-through the `-secret` and `-parameter` flags to allow setting
parameters for the snapshot and overriding the secrets we've stored on
the CSI volume in the state store.
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
When a node is drained, system jobs are left until last so that
operators can rely on things like log shippers running even as their
applications are getting drained off. Include CSI plugins in this set
so that Controller plugins deployed as services can be handled as
gracefully as Node plugins that are running as system jobs.
The previous output of the `nomad server members` command would output a
column named `Protocol` that displayed the Serf protocol being currently
used by servers.
This is not a configurable option, so it holds very little value to
operators. It is also easy to confuse it with the Raft Protocol version,
which is configurable and highly relevant to operators.
This commit replaces the previous `Protocol` column with the new `Raft
Version`. It also updates the `-detailed` flag to be called `-verbose`
so it matches other commands. The detailed output now also outputs the
same information as the standard output with the addition of the
previous `Protocol` column and `Tags`.
When a Nomad server becomes the Raft leader, it must perform several
actions defined in the establishLeadership function. If any of these
actions fail, Raft will think the node is the leader, but it will not
actually be able to act as a Nomad leader.
In this scenario, leadership must be revoked and transferred to another
server if possible, or the node should retry the establishLeadership
steps.
Clarify the behavior of `restart` inheritance with respect to Connect
sidecar tasks. Remove incorrect language about the scheduler being
involved in restart decisions. Try to make the `delay` mode
documentation more clear, and provide examples of delay vs fail.
The Docker DNS configuration options are not compatible with a
group-level network in `bridge` mode. Warn users about this in the
Docker task configuration docs.
The RPC for listing volume snapshots requires a plugin ID. Update the
`volume snapshot list` command to find the specific plugin from the
provided prefix.
The advertise.rpc config option is not intuitive. At first glance you'd
assume it works like advertise.http or advertise.serf, but it does not.
The current behavior is working as intended, but the documentation is
very hard to parse and doesn't draw a clear picture of what the setting
actually does.
Closes https://github.com/hashicorp/nomad/issues/11075
The dynamic plugin registry assumes that plugins are singletons, which
matches the behavior of other Nomad plugins. But because dynamic
plugins like CSI are implemented by allocations, we need to handle the
possibility of multiple allocations for a given plugin type + ID, as
well as behaviors around interleaved allocation starts and stops.
Update the data structure for the dynamic registry so that more recent
allocations take over as the instance manager singleton, but we still
preserve the previous running allocations so that restores work
without racing.
Multiple allocations can run on a client for the same plugin, even if
only during updates. Provide each plugin task a unique path for the
control socket so that the tasks don't interfere with each other.
Nomad inherited protocol version numbering configuration from Consul and
Serf, but unlike those projects Nomad has never used it. Nomad's
`protocol_version` has always been `1`.
While the code is effectively unused and therefore poses no runtime
risks to leave, I felt like removing it was best because:
1. Nomad's RPC subsystem has been able to evolve extensively without
needing to increment the version number.
2. Nomad's HTTP API has evolved extensively without increment
`API{Major,Minor}Version`. If we want to version the HTTP API in the
future, I doubt this is the mechanism we would choose.
3. The presence of the `server.protocol_version` configuration
parameter is confusing since `server.raft_protocol` *is* an important
parameter for operators to consider. Even more confusing is that
there is a distinct Serf protocol version which is included in `nomad
server members` output under the heading `Protocol`. `raft_protocol`
is the *only* protocol version relevant to Nomad developers and
operators. The other protocol versions are either deadcode or have
never changed (Serf).
4. If we were to need to version the RPC, HTTP API, or Serf protocols, I
don't think these configuration parameters and variables are the best
choice. If we come to that point we should choose a versioning scheme
based on the use case and modern best practices -- not this 6+ year
old dead code.
