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!"
Fixes#13505
This fixes#13505 by treating reserved_ports like we treat a lot of jobspec settings: merging settings from more global stanzas (client.reserved.reserved_ports) "down" into more specific stanzas (client.host_networks[].reserved_ports).
As discussed in #13505 there are other options, and since it's totally broken right now we have some flexibility:
Treat overlapping reserved_ports on addresses as invalid and refuse to start agents. However, I'm not sure there's a cohesive model we want to publish right now since so much 0.9-0.12 compat code still exists! We would have to explain to folks that if their -network-interface and host_network addresses overlapped, they could only specify reserved_ports in one place or the other?! It gets ugly.
Use the global client.reserved.reserved_ports value as the default and treat host_network[].reserverd_ports as overrides. My first suggestion in the issue, but @groggemans made me realize the addresses on the agent's interface (as configured by -network-interface) may overlap with host_networks, so you'd need to remove the global reserved_ports from addresses shared with a shared network?! This seemed really confusing and subtle for users to me.
So I think "merging down" creates the most expressive yet understandable approach. I've played around with it a bit, and it doesn't seem too surprising. The only frustrating part is how difficult it is to observe the available addresses and ports on a node! However that's a job for another PR.
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 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>
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.
Log the failure error when the agent fails to start. Previously, the
agent startup failure error would be emitted to the command UI but not
logged. So it doesn't get emitted to syslog or `log_file` if they are
set, and it makes debugging much harder. Also, logging the error again
before exit makes the error more visible: previously, the operator
needed to scroll to the top to find the error.
On a sample failure, the output will look like:
```
==> WARNING: Bootstrap mode enabled! Potentially unsafe operation.
==> Loaded configuration from sample-configs/config-bad
==> Starting Nomad agent...
==> Error starting agent: setting up server node ID failed: mkdir /path-without-permission: read-only file system
2021-10-20T14:38:51.179-0400 [WARN] agent.plugin_loader: skipping external plugins since plugin_dir doesn't exist: plugin_dir=/path-without-permission/plugins
2021-10-20T14:38:51.181-0400 [DEBUG] agent.plugin_loader.docker: using client connection initialized from environment: plugin_dir=/path-without-permission/plugins
2021-10-20T14:38:51.181-0400 [DEBUG] agent.plugin_loader.docker: using client connection initialized from environment: plugin_dir=/path-without-permission/plugins
2021-10-20T14:38:51.181-0400 [INFO] agent: detected plugin: name=java type=driver plugin_version=0.1.0
2021-10-20T14:38:51.181-0400 [INFO] agent: detected plugin: name=docker type=driver plugin_version=0.1.0
2021-10-20T14:38:51.181-0400 [INFO] agent: detected plugin: name=mock_driver type=driver plugin_version=0.1.0
2021-10-20T14:38:51.181-0400 [INFO] agent: detected plugin: name=raw_exec type=driver plugin_version=0.1.0
2021-10-20T14:38:51.181-0400 [INFO] agent: detected plugin: name=exec type=driver plugin_version=0.1.0
2021-10-20T14:38:51.181-0400 [INFO] agent: detected plugin: name=qemu type=driver plugin_version=0.1.0
2021-10-20T14:38:51.181-0400 [ERROR] agent: error starting agent: error="setting up server node ID failed: mkdir /path-without-permission: read-only file system"
```
This change adds the final `ERROR` message. It's easy to miss the `==>
Error starting agent` above.
Ensure that `""` Scheduler Algorithm gets explicitly set to binpack on
upgrades or on API handling when user misses the value.
The scheduler already treats `""` value as binpack. This PR merely
ensures that the operator API returns the effective value.
Shutdown http server last, after nomad client/server components
terminate.
Before this change, if the agent is taking an unexpectedly long time to
shutdown, the operator cannot query the http server directly: they
cannot access agent specific http endpoints and need to query another
agent about the troublesome agent.
Unexpectedly long shutdown can happen in normal cases, e.g. a client
might hung is if one of the allocs it is running has a long
shutdown_delay.
Here, we switch to ensuring that the http server is shutdown last.
I believe this doesn't require extra care in agent shutting down logic
while operators may be able to submit write http requests. We already
need to cope with operators submiting these http requests to another
agent or by servers updating the client allocations.
allow oss to parse sink duration
clean up audit sink parsing
ent eventer config reload
fix typo
SetEnabled to eventer interface
client acl test
rm dead code
fix failing test
Nomad jobs may be configured with a TaskGroup which contains a Service
definition that is Consul Connect enabled. These service definitions end
up establishing a Consul Connect Proxy Task (e.g. envoy, by default). In
the case where Consul ACLs are enabled, a Service Identity token is required
for these tasks to run & connect, etc. This changeset enables the Nomad Server
to recieve RPC requests for the derivation of SI tokens on behalf of instances
of Consul Connect using Tasks. Those tokens are then relayed back to the
requesting Client, which then injects the tokens in the secrets directory of
the Task.
This change provides an initial pass at setting up the configuration necessary to
enable use of Connect with Consul ACLs. Operators will be able to pass in a Consul
Token through `-consul-token` or `$CONSUL_TOKEN` in the `job run` and `job revert`
commands (similar to Vault tokens).
These values are not actually used yet in this changeset.
This is the basic code to add the Windows Service Manager hooks to Nomad.
Includes vendoring golang.org/x/sys/windows/svc and added Docs:
* guide for installing as a windows service.
* configuration for logging to file from PR #6429
Adds new package that can be used by client and server RPC endpoints to
facilitate monitoring based off of a logger
clean up old code
small comment about write
rm old comment about minsize
rename to Monitor
Removes connection logic from monitor command
Keep connection logic in endpoints, use a channel to send results from
monitoring
use new multisink logger and interfaces
small test for dropped messages
update go-hclogger and update sink/intercept logger interfaces
AgentMonitor is an endpoint to stream logs for a given agent. It allows
callers to pass in a supplied log level, which may be different than the
agents config allowing for temporary debugging with lower log levels.
Pass in logWriter when setting up Agent
