Co-authored-by: Luiz Aoqui <luiz@hashicorp.com>

This PR checks server config for raft_protocol, which must now
be set to 3 or unset (0). When unset, version 3 is used as the
default.

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 test exercises upgrades between 0.8 and Nomad versions greater
than 0.9. We have not supported 0.8.x in a very long time and in any
case the test has been marked to skip because the downloader doesn't
work.

This PR updates the changelog, adds notes the 1.3 upgrade guide, and
updates the connect integration docs with documentation about the new
requirement on Consul ACL policies of Consul agent default anonymous ACL
tokens.

This PR expands on the work done in #12543 to
- prefix the tag, so it is now "nomad.alloc_id" to be more consistent with Consul tags
- merge into pre-existing envoy_stats_tags fields
- update the upgrade guide docs
- update changelog

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.html

Closes #11289
Fixes #11705 #11773 #11933

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.

This PR swaps the underlying BoltDB implementation from boltdb/bolt
to go.etc.io/bbolt.

In addition, the Server has a new configuration option for disabling
NoFreelistSync on the underlying database.

Freelist option: https://github.com/etcd-io/bbolt/blob/master/db.go#L81
Consul equivelent PR: https://github.com/hashicorp/consul/pull/11720

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.

Many of Nomad's Autopilot features require raft protocol version
3. Set the default raft protocol to 3, and improve the upgrade
documentation.

Use the new filtering and pagination capabilities of the `Eval.List`
RPC to provide filtering and pagination at the command line.

Also includes note that `nomad eval status -json` is deprecated and
will be replaced with a single evaluation view in a future version of
Nomad.

Co-authored-by: Luiz Aoqui <luiz@hashicorp.com>
Co-authored-by: Mike Nomitch <mnomitch@hashicorp.com>

Co-authored-by: Derek Strickland <1111455+DerekStrickland@users.noreply.github.com>

* don't timestamp active log file

* website: update log_file default value

* changelog: add entry for #11070

* website: add upgrade instructions for log_file in v1.14 and v1.2.0

Fixes #11002

In Nomad 1.1.1 we generate a hosts file based on the Nomad-owned network
namespace, rather than using the default hosts file from the pause
container. This hosts file should be shared between tasks in the same
allocation so that tasks can update the file and have the results propagated
between tasks.

The `docker` driver's `port_map` field was deprecated in 0.12 and this is
documented in the task driver's docs, but we never explicitly flagged it for
backwards compatibility.

drivers/exec+java: reduce default set of linux capabilities

Update docs for allow_caps, cap_add, cap_drop in exec/java/docker driver
pages. Also update upgrade guide with guidance on new default linux
capabilities for exec and java drivers.