Plan rejections occur when the scheduler work and the leader plan
applier disagree on the feasibility of a plan. This may happen for valid
reasons: since Nomad does parallel scheduling, it is expected that
different workers will have a different state when computing placements.
As the final plan reaches the leader plan applier, it may no longer be
valid due to a concurrent scheduling taking up intended resources. In
these situations the plan applier will notify the worker that the plan
was rejected and that they should refresh their state before trying
again.
In some rare and unexpected circumstances it has been observed that
workers will repeatedly submit the same plan, even if they are always
rejected.
While the root cause is still unknown this mitigation has been put in
place. The plan applier will now track the history of plan rejections
per client and include in the plan result a list of node IDs that should
be set as ineligible if the number of rejections in a given time window
crosses a certain threshold. The window size and threshold value can be
adjusted in the server configuration.
To avoid marking several nodes as ineligible at one, the operation is rate
limited to 5 nodes every 30min, with an initial burst of 10 operations.
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.
FailoverHeartbeatTTL is the amount of time to wait after a server leader failure
before considering reallocating client tasks. This TTL should be fairly long as
the new server leader needs to rebuild the entire heartbeat map for the
cluster. In deployments with a small number of machines, the default TTL (5m)
may be unnecessary long. Let's allow operators to configure this value in their
config files.
* remove event durability
temporarily removing go-memdb event durability until a new strategy is developed on how to best handled increased durability needs
* drop events table schema and state store methods
* fix neweventbuffer invocations
properly wire up durable event count
move newline responsibility
moves newline creation from NDJson to the http handler, json stream only encodes and sends now
ignore snapshot restore if broker is disabled
enable dev mode to access event steam without acl
use mapping instead of switch
use pointers for config sizes, remove unused ttl, simplify closed conn logic
This changeset implements a periodic garbage collection of CSI volumes
with missing allocations. This can happen in a scenario where a node
update fails partially and the allocation updates are written to raft
but the evaluations to GC the volumes are dropped. This feature will
cover this edge case and ensure that upgrades from 0.11.0 and 0.11.1
get any stray claims cleaned up.
This changeset implements a periodic garbage collection of unused CSI
plugins. Plugins are self-cleaning when the last allocation for a
plugin is stopped, but this feature will cover any missing edge cases
and ensure that upgrades from 0.11.0 and 0.11.1 get any stray plugins
cleaned up.
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
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 exposes a client flag to disable nomad remote exec support in
environments where access to tasks ought to be restricted.
I used `disable_remote_exec` client flag that defaults to allowing
remote exec. Opted for a client config that can be used to disable
remote exec globally, or to a subset of the cluster if necessary.
