Add an updated `target_ec2_instances` module that is capable of
dynamically splitting target instances over subnet/az's that are
compatible with the AMI architecture and the associated instance type
for the architecture. Use the `target_ec2_instances` module where
necessary. Ensure that `raft` storage scenarios don't provision
unnecessary infrastructure with a new `target_ec2_shim` module.
After a lot of trial, the state of Ec2 spot instance capacity, their
associated APIs, and current support for different fleet types in AWS
Terraform provider, have proven to make using spot instances for
scenario targets too unreliable.
The current state of each method:
* `target_ec2_fleet`: unusable due to the fact that the `instant` type
does not guarantee fulfillment of either `spot` or `on-demand`
instance request types. The module does support both `on-demand` and
`spot` request types and is capable of bidding across a maximum of
four availability zones, which makes it an attractive choice if the
`instant` type would always fulfill requests. Perhaps a `request` type
with `wait_for_fulfillment` option like `aws_spot_fleet_request` would
make it more viable for future consideration.
* `target_ec2_spot_fleet`: more reliable if bidding for target instances
that have capacity in the chosen zone. Issues in the AWS provider
prevent us from bidding across multiple zones succesfully. Over the
last 2-3 months target capacity for the instance types we'd prefer to
use has dropped dramatically and the price is near-or-at on-demand.
The volatility for nearly no cost savings means we should put this
option on the shelf for now.
* `target_ec2_instances`: the most reliable method we've got. It is now
capable of automatically determing which subnets and availability
zones to provision targets in and has been updated to be usable for
both Vault and Consul targets. By default we use the cheapest medium
instance types that we've found are reliable to test vault.
* Update .gitignore
* enos/modules/create_vpc: create a subnet for every availability zone
* enos/modules/target_ec2_fleet: bid across the maximum of four
availability zones for targets
* enos/modules/target_ec2_spot_fleet: attempt to make the spot fleet bid
across more availability zones for targets
* enos/modules/target_ec2_instances: create module to use
ec2:RunInstances for scenario targets
* enos/modules/target_ec2_shim: create shim module to satisfy the
target module interface
* enos/scenarios: use target_ec2_shim for backend targets on raft
storage scenarios
* enos/modules/az_finder: remove unsed module
Signed-off-by: Ryan Cragun <me@ryan.ec>
Co-authored-by: Ryan Cragun <me@ryan.ec>
The previous strategy for provisioning infrastructure targets was to use
the cheapest instances that could reliably perform as Vault cluster
nodes. With this change we introduce a new model for target node
infrastructure. We've replaced on-demand instances for a spot
fleet. While the spot price fluctuates based on dynamic pricing,
capacity, region, instance type, and platform, cost savings for our
most common combinations range between 20-70%.
This change only includes spot fleet targets for Vault clusters.
We'll be updating our Consul backend bidding in another PR.
* Create a new `vault_cluster` module that handles installation,
configuration, initializing, and unsealing Vault clusters.
* Create a `target_ec2_instances` module that can provision a group of
instances on-demand.
* Create a `target_ec2_spot_fleet` module that can bid on a fleet of
spot instances.
* Extend every Enos scenario to utilize the spot fleet target acquisition
strategy and the `vault_cluster` module.
* Update our Enos CI modules to handle both the `aws-nuke` permissions
and also the privileges to provision spot fleets.
* Only use us-east-1 and us-west-2 in our scenario matrices as costs are
lower than us-west-1.
Signed-off-by: Ryan Cragun <me@ryan.ec>
Sarah Thompson